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Review on Algorithms for dynamical fermions: This review gives an overview on the research of algorithms for dynamical fermions used in large scale lattice QCD simulations. First a short overview on the state-of-the-art of ensemble generation at the physical point is given. Followed by an overview on necessary step...
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Non-perturbative calculation of Z_m using Asqtad fermions: We report progress on a non-perturbative calculation of the light quark mass renormalization factor Z_m, using dynamical Asqtad fermions. This quantity is used to determine the light quark masses in the conventional MS-bar scheme. Such a non-perturbative determ...
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Supercurrent conservation in the lattice Wess-Zumino model with Ginsparg-Wilson fermions: We study supercurrent conservation for the four-dimensional Wess-Zumino model formulated on the lattice. The formulation is one that has been discussed several times, and uses Ginsparg-Wilson fermions of the overlap (Neuberger) ...
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Numerical sign problem and the tempered Lefschetz thimble method: The numerical sign problem is a major obstacle to the quantitative understanding of many important physical systems with first-principles calculations. Typical examples for such systems include finite-density QCD, strongly-correlated electron systems and...
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Condensation of vortices in the X-Y model in 3d: a disorder parameter: A disorder parameter is constructed which signals the condensation of vortices. The construction is tested by numerical simulations on lattice.
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From confinement to new states of dense QCD matter: Transitions between centre sectors are related to confinement in pure Yang-Mills theories. We study the impact of these transitions in QCD-like theories for which centre symmetry is explicitly broken by the presence of matter. For low temperatures, we provide numerica...
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A density of states approach to the hexagonal Hubbard model at finite density: We apply the Linear Logarithmic Relaxation (LLR) method, which generalizes the Wang-Landau algorithm to quantum systems with continuous degrees of freedom, to the fermionic Hubbard model with repulsive interactions on the honeycomb lattice...
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Status of the QCDOC project: A status report is given of the QCDOC project, a massively parallel computer optimized for lattice QCD using system-on-a-chip technology. We describe several of the hardware and software features unique to the QCDOC architecture and present performance figures obtained from simulating the c...
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Ordering monomial factors of polynomials in the product representation: The numerical construction of polynomials in the product representation (as used for instance in variants of the multiboson technique) can become problematic if rounding errors induce an imprecise or even unstable evaluation of the polynomial. We g...
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The Renormalized Trajectory of the O(N) Non-linear Sigma Model: The renormalized trajectory (RT) is determined from two different Monte Carlo renormalization group techniques with $\delta$-function block spin transformation in the multi-dimensional coupling parameter space of the two-dimensional non-linear sigma model ...
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Polynomial Hybrid Monte Carlo algorithm for lattice QCD with an odd number of flavors: We present a polynomial hybrid Monte Carlo (PHMC) algorithm for lattice QCD with odd numbers of flavors of O(a)-improved Wilson quark action. The algorithm makes use of the non-Hermitian Chebyshev polynomial to approximate the inve...
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Cascade Baryon Spectrum from Lattice QCD: A comprehensive study of the cascade baryon spectrum using lattice QCD affords the prospect of predicting the masses of states not yet discovered experimentally, and determining the spin and parity of those states for which the quantum numbers are not yet known. The study of th...
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Domain-wall fermions with U(1) dynamical gauge fields in (4+1)-dimensions: We carry out a numerical simulation of a domain-wall model in (4+1) dimensions, in the presence of a quenched U(1) dynamical gauge field only in an extra dimension, corresponding to the weak coupling limit of a (4-dimensional) physical gauge c...
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Towards reduction of autocorrelation in HMC by machine learning: In this paper we propose new algorithm to reduce autocorrelation in Markov chain Monte-Carlo algorithms for euclidean field theories on the lattice. Our proposing algorithm is the Hybrid Monte-Carlo algorithm (HMC) with restricted Boltzmann machine. We ex...
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On Scale Determination in Lattice QCD with Dynamical Quarks: Dependence of a/r_c (inverse Sommer parameter in units of lattice spacing a) on am_q (quark mass in lattice unit) has been observed in all lattice QCD simulations with sea quarks including the ones with improved actions. How much of this dependence is a scali...
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Split of the pseudo-critical temperatures of chiral and confine/deconfine transitions by temperature gradient: Searching of the critical endpoint of the phase transition of Quantum Chromodynamics~(QCD) matter in experiments is of great interest. The temperature in the fireball of a collider is location dependent, how...
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B- and D-meson leptonic decay constants and quark masses from four-flavor lattice QCD: We describe a recent lattice-QCD calculation of the leptonic decay constants of heavy-light pseudoscalar mesons containing charm and bottom quarks and of the masses of the up, down, strange, charm, and bottom quarks. Results for th...
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Taste breaking effects in scalar meson correlators: As a consistency check of the staggered-fermion fourth-root approximation, we analyze the a_0 and f_0 correlators, including the effects of two-meson taste-multiplet intermediate states. Rooted staggered chiral perturbation theory describes the contributions from the ...
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Pion condensation at lower than physical quark masses: In QCD at large enough isospin chemical potential Bose-Einstein Condensation (BEC) takes place, separated from the normal phase by a phase transition. From previous studies the location of the BEC line at the physical point is known. In the chiral limit the condens...
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Recent progress in finite temperature lattice QCD: I review recent progress in the determination of the QCD phase diagram at finite temperature, in investigations of the nature of the transition or crossover from the hadronic phase to the quark-gluon plasma phase and in the determination of the equation of state. This ...
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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 B to K/K*l+l- semi-leptonic decay form factors.
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Meson spectral functions at nonzero momentum in hot QCD: We present preliminary results for meson spectral functions at nonzero momentum, obtained from quenched lattice QCD simulations at finite temperature using the Maximal Entropy Method. Twisted boundary conditions are used to have access to many momenta p~T. For li...
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No coincidence of center percolation and deconfinement in SU(4) lattice gauge theory: We study the behavior of center sectors in pure SU(4) lattice gauge theory at finite temperature. The center sectors are defined as spatial clusters of neighboring sites with values of their local Polyakov loops near the same center...
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Asymptotically free models and discrete non-Abelian groups: We study the two-dimensional renormalization-group flow induced by perturbations that reduce the global symmetry of the O(3) sigma-model to the discrete symmetries of Platonic solids. We estimate the value of the correlation length at which differences in the ...
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Precise Determination of the Charm Quark Mass: The determination of the charm quark mass is now possible to 1% from QCD, with lattice QCD pushing the error down below 1%. I will describe the ingredients of this approach and how it can achieve this accuracy. Results for quark mass ratios, m_c/m_s and m_b/m_c, can also b...
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Improved Error Estimate for the Valence Approximation: We construct a systematic mean-field-improved coupling constant and quark loop expansion for corrections to the valence (quenched) approximation to vacuum expectation values in the lattice formulation of QCD. Terms in the expansion are evaluated by a combination of...
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Restoring rotational invariance for lattice QCD propagators: This note presents a method to reduce the discretization errors appearing when solving a Quantum Field Theory in a hypercubic lattice in both position and momentum-space. The method exploits the artifacts that break rotational symmetry to recover rotationally...
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Progress Towards finding Quark Masses and the QCD scale Lambda from the Lattice: We discuss recent work trying to extract the renormalised quark masses and Lambda, the QCD scale, from dynamical simulations in lattice gauge theory.
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Topological Features in a Two-Dimensional Higgs Model: Topological properties of the gauge field in a two-dimensional Higgs model are investigated. Results of exploratory numerical simulations are presented.
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Confinement Physics in Quantum Chromodynamics: We study the confinement physics in QCD in the maximally abelian (MA) gauge using the SU(2) lattice QCD, based on the dual-superconductor picture. In the MA gauge, off-diagonal gluon components are forced to be small, and the off-diagonal angle variable $\chi_\mu(s)$ tends...
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The lattice Schwinger model as a discrete sum of filled Wilson loops: Using techniques from hopping expansion we identically map the lattice Schwinger model with Wilson fermions to a model of oriented loops on the lattice. This is done by first computing the explicit form of the fermion determinant in the external fiel...
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Toward the excited isoscalar meson spectrum from lattice QCD: We report on the extraction of an excited spectrum of isoscalar mesons using lattice QCD. Calculations on several lattice volumes are performed with a range of light quark masses corresponding to pion masses down to about 400 MeV. The distillation method ena...
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The finite temperature QCD using 2+1 flavors of domain wall fermions at N_t = 8: We study the region of the QCD phase transition using 2+1 flavors of domain wall fermions (DWF) and a $16^3 \times 8$ lattice volume with a fifth dimension of $L_s = 32$. The disconnected light quark chiral susceptibility, quark number s...
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Charm quark mass and D-meson decay constants from two-flavour lattice QCD: We present a computation of the charm quark's mass and the leptonic D-meson decay constants f_D and f_{D_s} in two-flavour lattice QCD with non-perturbatively O(a) improved Wilson quarks. Our analysis is based on the CLS configurations at two ...
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Thermodynamic Study for Conformal Phase in Large Nf Gauge Theory: We investigate the chiral phase transition at finite temperature (T) in colour SU(3) Quantum Chromodynamics (QCD) with six species of fermions (Nf = 6) in the fundamental representation. The simulations have been performed by using lattice QCD with impro...
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Wilson Fermions, Random Matrix Theory and the Aoki Phase: The QCD partition function for the Wilson Dirac operator, $D_W$, at nonzero lattice spacing $a$ can be expressed in terms of a chiral Lagrangian as a systematic expansion in the quark mass, the momentum and $a^2$. Starting from this chiral Lagrangian we obtain a...
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Proton and neutron electromagnetic radii and magnetic moments from lattice QCD: We present results for the electromagnetic form factors of the proton and neutron computed on the $(2 + 1)$-flavor Coordinated Lattice Simulations (CLS) ensembles including both quark-connected and -disconnected contributions. The $Q^2$-,...
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Glueball spectroscopy in lattice QCD using gradient flow: Removing ultraviolet noise from the gauge fields is necessary for glueball spectroscopy in lattice QCD. It is known that the Yang-Mills gradient flow method is an alternative approach instead of link smearing or link fuzzing in various aspects. In this work we s...
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Current status of $\varepsilon_K$ in lattice QCD: We present the current status of $\varepsilon_K$ evaluated directly from the standard model using lattice QCD inputs. The lattice QCD inputs include $\hat{B}_K$, $\xi_0$, $\xi_2$, $|V_{us}|$, $m_c(m_c)$, and $|V_{cb}|$. Recently, FLAG has updated $\hat{B}_K$, exclusive ...
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Sensitivity of the Polyakov loop to chiral symmetry restoration: In the heavy, static quark mass regime of QCD, the Polyakov loop is well known to be an order parameter of the deconfinement phase transition; however, the sensitivity of the Polyakov loop to the deconfinement of light, dynamical quarks is less clear. On ...
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Numerical Evaluation of a Soliton Pair with Long Range Interaction: Within the model of topological particles (MTP) we determine the interaction energy of monopole pairs, sources and sinks of a Coulombic field. The monopoles are represented by topological solitons of finite size and mass, described by a field without a...
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Recent Developments in Dual Lattice Algorithms: We review recent progress in numerical simulations with dually transformed SU(2) LGT, starting with a discussion of explicit dual amplitudes and algorithms for SU(2) pure Yang Mills in D=3 and D=4. In the D=3 case, we discuss results that validate the dual algorithm again...
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Renormalization Group Therapy: We point out a general problem with the procedures commonly used to obtain improved actions from MCRG decimated configurations. Straightforward measurement of the couplings from the decimated configurations, by one of the known methods, can result into actions that do not correctly reprod...
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Lattice QCD Impact on Determination of the CKM Matrix: We review many lattice QCD calculations that impact the precise determination of the CKM matrix. We focus on decay constants and semileptonic form factors of both light ($\pi$ and K) and heavy-light ($D_{(s)}$ and $B_{(s)}$) mesons. Implication of $\Lambda_b$ form ...
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Confining Classical Configurations: We construct a family of smooth, almost self-dual, non-thermalized SU(2) gauge field configurations, and measure the average of the fundamental, adjoint and spin $\frac{3}{2}$ representation Wilson loops on them. We get area law in all three cases. We also study thermalised configura...
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A classification of 2-dim Lattice Theory: A unified classification and analysis is presented of two dimensional Dirac operators of QCD-like theories in the continuum as well as in a naive lattice discretization. Thereby we consider the quenched theory in the strong coupling limit. We do not only consider the case of a ...
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QCD with domain wall quarks: We present lattice calculations in QCD using a variant of Kaplan fermions which retain the continuum SU(N)xSU(N) chiral symmetry on the lattice in the limit of an infinite extra dimension. In particular, we show that the pion mass and the four quark matrix element related to K_0-K_0-bar mix...
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Improved gradient flow for step scaling function and scale setting: The gradient flow renormalized coupling offers a simple and relatively inexpensive way to calculate the step scaling function and the lattice scale, but both applications can be hindered by large lattice artifacts. Recently we introduced an empirical n...
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Radiative transitions in charmonium from $N_f=2$ twisted mass lattice QCD: We present a study for charmonium radiative transitions: $J/\psi\rightarrow\eta_c\gamma$, $\chi_{c0}\rightarrow J/\Psi\gamma$ and $h_c\rightarrow\eta_c\gamma$ using $N_f=2$ twisted mass lattice QCD gauge configurations. The single-quark vector...
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Warped Domain Wall Fermions: We consider Kaplan's domain wall fermions in the presence of an Anti-de Sitter (AdS) background in the extra dimension. Just as in the flat space case, in a completely vector-like gauge theory defined after discretizing this extra dimension, the spectrum contains a very light charged fermio...
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Rigidity and percolation of center vortices: Effective action of center vortices in SU(2) lattice gauge theory is investigated by studying the correlation between the action density on their worldsheets and their geometric properties. It turns out that center vortices are rigid, however, their dynamics is more complica...
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Study of intermediate states in the inclusive semileptonic $B \rightarrow X_c l ν$ decay structure function: We analyze the inclusive semileptonic $B \to X_c \ell\nu$ structure functions in 2+1-flavor lattice QCD. The M\"obius domain-wall fermion action is used for light, strange, charm and bottom quarks. The structu...
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Excited States of U(1)$_{2+1}$ Lattice Gauge Theory from Monte Carlo Hamiltonian: We address an old problem in lattice gauge theory - the computation of the spectrum and wave functions of excited states. Our method is based on the Hamiltonian formulation of lattice gauge theory. As strategy, we propose to construct a...
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Hadron Spectrum and Matrix Elements in QCD with Dynamical Wilson Fermions at 6/g^2=5.3: We present results of a lattice simulation of quantum chromodynamics with two degenerate flavors of dynamic Wilson fermions at $6/g^2=5.3$ at each of two dynamical fermion hopping parameters, $\kappa=0.1670$ and 0.1675, correspond...
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Topological Fluctuations in Dense Matter with Two Colors: We study the topological charge fluctuations of an SU(2) lattice gauge theory containing both N_f=2 and 4 flavors of Wilson fermion, at low temperature with non-zero chemical potential $\mu$. The topological susceptibility, chi_T, is used to characterize differi...
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Lattice Gauge Fields Topology Uncovered by Quaternionic sigma-model Embedding: We investigate SU(2) gauge fields topology using new approach, which exploits the well known connection between SU(2) gauge theory and quaternionic projective sigma-models and allows to formulate the topological charge density entirely in ...
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Gradient flow, confinement, and magnetic monopole in U(1) lattice gauge theory: In the gradient flow method of lattice gauge theory, coarse graining is performed so as to reduce the action, and as the coarse graining progresses, the field strength becomes very small. However, the confinement property that particles i...
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Fermi point in graphene as a monopole in momentum space: We consider the effective field theory of graphene monolayer with the Coulomb interaction between fermions taken into account. The gauge field in momentum space is introduced. The position of the Fermi point coincides with the position of the corresponding monopo...
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Staggered fermions and their $O(a)$ improvements: Expanding upon the arguments of Sharpe, we explicitly implement the Symanzik improvement program demonstrating the absence of order $a$ terms in the staggered fermion action. We propose a general program to improve fermion operators to remove $O(a)$ corrections from the...
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Identifying spin and parity of charmonia in flight with lattice QCD: The spectrum of charmonium resonances contains a number of unanticipated states along with several conventional quark-model excitations. The hadrons of different quantum numbers $J^P$ appear in a fairly narrow energy band, where $J^P$ refers to the sp...
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Spontaneous symmetry breaking via inhomogeneities and the differential surface tension: We discuss spontaneously broken quantum field theories with a continuous symmetry group via the constraint effective potential. Employing lattice simulations with constrained values of the order parameter, we demonstrate explicitl...
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GomalizingFlow.jl: A Julia package for Flow-based sampling algorithm for lattice field theory: GomalizingFlow.jl: is a package to generate configurations for quantum field theory on the lattice using the flow based sampling algorithm in Julia programming language. This software serves two main purposes: to accelerate...
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Weak Decays of Heavy-Light Mesons on the Lattice: Semi-Leptonic Formfactors: We report results (on an intermediate statistics sample) of a study of weak semi-leptonic formfactors of $B$ and $D$ decays, addressing the uncertainties from mass extrapolations to chiral and to heavy quarks. Moreover, we present a nonpertu...
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Vortices, monopoles and confinement: We construct the creation operator of a vortex using the methods developed for monopoles. The vacuum expectation value of this operator is interpreted as a disorder parameter describing vortex condensation and is studied numerically on a lattice in SU(2) gauge theory. The result is ...
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Dynamically-coupled partial-waves in $ρπ$ isospin-2 scattering from lattice QCD: We present the first determination of $\rho \pi$ scattering, incorporating dynamically-coupled partial-waves, using lattice QCD, a first-principles numerical approach to QCD. Considering the case of isospin-2 $\rho \pi$, we calculate par...
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Contour deformations for non-holomorphic actions: We show how contour deformations may be used to control the sign problem of lattice Monte Carlo calculations with non-holomorphic actions. Such actions arise naturally in quantum mechanical scattering problems. The approach is demonstrated in conjunction with the holomo...
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Comparing meson-meson and diquark-antidiquark creation operators for a $\bar b \bar b u d$ tetraquark: We compare two frequently discussed competing structures for a stable $\bar b \bar b u d$ tetraquark with quantum numbers $I(J^P) = 0(1^+)$ by considering a meson-meson as well as a diquark-antidiquark creation oper...
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Numerical Study of Dense Adjoint Matter in Two Color QCD: We identify the global symmetries of SU(2) lattice gauge theory with N flavors of staggered fermion in the presence of a quark chemical potential mu, for fermions in both fundamental and adjoint representations, and anticipate likely patterns of symmetry breakin...
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Meson screening masses at finite temperature with Highly Improved Staggered Quarks: We report on the first study of the screening properties of the mesonic excitations with strange ($s$) and charm ($c$) quarks, specifically the ground states of the pseudo-scalar and vector meson excitations for the $\bar{s}s$, $\bar{...
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The pion quasiparticle in the low-temperature phase of QCD: We investigate the properties of the pion quasiparticle in the low-temperature phase of two-flavor QCD on the lattice with support from chiral effective theory. We find that the pion quasiparticle mass is significantly reduced compared to its value in the vacu...
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Matrix product states for gauge field theories: The matrix product state formalism is used to simulate Hamiltonian lattice gauge theories. To this end, we define matrix product state manifolds which are manifestly gauge invariant. As an application, we study 1+1 dimensional one flavour quantum electrodynamics, also kno...
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Comparison of Improved and Unimproved Quenched Hadron Spectroscopy: We make a comparison between our quenched-hadron-spectroscopy results for the non-perturbatively-improved Wilson action and the corresponding unimproved case, at beta=6.2 on the same set of gauge configurations. Within our statistics, we find a sizeabl...
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Direct detection of metal-insulator phase transitions using the modified Backus-Gilbert method: The detection of the (semi)metal-insulator phase transition can be extremely difficult if the local order parameter which characterizes the ordered phase is unknown.In some cases, it is even impossible to define a local or...
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Cluster Percolation and Critical Behaviour in Spin Models and SU(N) Gauge Theories: The critical behaviour of several spin models can be simply described as percolation of some suitably defined clusters, or droplets: the onset of the geometrical transition coincides with the critical point and the percolation exponen...
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Nucleon Properties at Finite Volume: the Epsilon Prime Regime: We study the properties of the nucleon in highly asymmetric volumes where the spatial dimensions are small but the time dimension is large in comparison to the inverse pion mass. To facilitate power-counting at the level of Feynman diagrams, we introduce $\...
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Hadron form factors using density-density correlators: Gauge invariant density-density correlators yield detailed information on hadron structure. Hadron deformation and form factors can be extracted for momentum transfers up to about 6 GeV$^2$. We use stochastic techniques and dilution to compute the all to all propag...
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Proton momentum and angular momentum decompositions with overlap fermions: We present a calculation of the proton momentum and angular momentum decompositions using overlap fermions on a $2+1$-flavor RBC/UKQCD domain-wall lattice at 0.143 fm with a pion mass of 171 MeV which is close to the physical one. A complete d...
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Improved determination of $B_K$ with staggered quarks: We present results for the kaon mixing parameter $B_K$ obtained using improved staggered fermions on a much enlarged set of MILC asqtad lattices. Compared to our previous publication, which was based largely on a single ensemble at each of the three lattice spacing...
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The spectrum of lattice QCD with staggered fermions at strong coupling: Using 4 flavors of staggered fermions at infinite gauge coupling, we compare various analytic results for the hadron spectrum with exact Monte Carlo simulations. Agreement with Ref. \cite{Martin_etal} is very good, at the level of a few percent. ...
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Twist free energy and critical behavior of 3D U(1) LGT at finite temperature: The twist free energy is computed in the Villain formulation of the 3D U(1) lattice gauge theory at finite temperature. This enables us to obtain renormalization group equations describing a critical behavior of the model in the vicinity of...
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Gauge-invariant nonlocal quark condensates in QCD: We study, by numerical simulations on a lattice, the behaviour of the gauge-invariant nonlocal quark condensates in the QCD vacuum both in the quenched approximation and with four flavours of dynamical staggered fermions. The correlation length of the condensate is det...
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The phase diagram of the three-dimensional Z2 gauge Higgs system at zero and finite temperature: We study the effect of adding a matter field to the Z2 gauge model in three dimensions at zero and finite temperature. Up to a given value of the parameter regulating the coupling, the matter field produces a slight shift...
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Static quark-antiquark potential in the quark-gluon plasma from lattice QCD: We present a state-of-the-art determination of the complex valued static quark-antiquark potential at phenomenologically relevant temperatures around the deconfinement phase transition. Its values are obtained from non-perturbative lattice Q...
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Numerical study of chiral magnetic effect in quenched SU(2) lattice gauge theory: A possible experimental observation of the chiral magnetic effect in heavy ion collisions at RHIC was recently reported by the STAR Collaboration. We study signatures of this effect in SU(2) lattice gluodynamics with the chirally invari...
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On isospin breaking in $τ$ decays for $(g-2)_μ$ from Lattice QCD: Hadronic spectral functions of $\tau$ decays have been used in the past to provide an alternative determination of the LO Hadronic Vacuum Polarization relevant for the (g-2) of the muon. Following recent developments and results in Lattice QCD+QED calcul...
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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 in connection with a restoration of the Leibniz rule in the limit $a\to0$ in perturbatively finite theory. We are interested in the difference between the Wilson and Ginsparg-Wilson fermions a...
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Scaling Properties of the Probability Distribution of Lattice Gribov Copies: We study the problem of the Landau gauge fixing in the case of the SU(2) lattice gauge theory. We show that the probability to find a lattice Gribov copy increases considerably when the physical size of the lattice exceeds some critical valu...
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Lattice-QCD Determination of the Hyperon Axial Couplings in the Continuum Limit: We present the first continuum extrapolation of the hyperon octet axial couplings ($g_{\Sigma \Sigma}$ and $g_{\Xi \Xi}$) from $N_f=2+1+1$ lattice QCD. These couplings are important parameters in the low-energy effective field theory des...
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Wilson fermions with imaginary chemical potential: We study the phase structure of imaginary chemical potential. We calculate the Polyakov loop using clover-improved Wilson action and renormalization improved gauge action. We obtain a two-state signals indicating the first order phase transition for $\beta = 1.9, \mu...
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Light Meson Distribution Amplitudes: We calculated the first two moments of the light-cone distribution amplitudes for the pseudoscalar mesons ($\pi$ and $K$) and the longitudinally polarised vector mesons ($\rho$, $K^*$ and $\phi$) as part of the UKQCD and RBC collaborations' $N_f=2+1$ domain-wall fermion phenomenolog...
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Wilson fermions with chirally twisted mass: Lattice formulations of QCD with Wilson fermions and a chirally twisted quark mass matrix provide an attractive framework for non-perturbative numerical studies. Owing to reparameterization invariance, the limiting continuum theory is just QCD. No spurious quark zero modes, w...
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Scattering of two and three physical pions at maximal isospin from lattice QCD: We present the first direct $N_f=2$ lattice QCD computation of two- and three-$\pi^+$ scattering quantities that includes an ensemble at the physical point. We study the quark mass dependence of the two-pion phase shift, and the three-par...
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Non-perturbative renormalization of tensor currents: strategy and results for $N_f = 0$ and $N_f = 2$ QCD: Tensor currents are the only quark bilinear operators lacking a non-perturbative determination of their renormalisation group (RG) running between hadronic and electroweak scales. We develop the setup to carry o...
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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 high temperature. This includes not only the restoration $SU(n_F)_L \times SU(n_F)_R$, but also the effective emergence of an unexpected symmetry group, namely $SU(2)_{...
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ΔS=2 and ΔC=2 bag parameters in the SM and beyond from Nf=2+1+1 twisted-mass LQCD: We present unquenched lattice QCD results for the matrix elements of four-fermion operators relevant to the description of the neutral K and D mixing in the Standard Model and its extensions. We have employed simulations with Nf = 2 + ...
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Algorithms for Lattice QCD with Dynamical Fermions: We consider recent progress in algorithms for generating gauge field configurations that include the dynamical effects of light fermions. We survey what has been achieved in recent state-of-the-art computations, and examine the trade-offs between performance and contr...
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A Lattice Study of Spectator Effects in Inclusive Decays of B-Mesons: We compute the matrix elements of the operators which contribute to spectator effects in inclusive decays of $B$-mesons. The results agree well with estimates based on the vacuum saturation (factorization) hypothesis. For the ratio of lifetimes of ch...
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Gauge theory of things alive and universal dynamics: Positing complex adaptive systems made of agents with relations between them that can be composed, it follows that they can be described by gauge theories similar to elementary particle theory and general relativity. By definition, a universal dynamics is able to det...
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Nucleon axial form factors using lattice QCD simulations with a physical value of the pion mass: We present results on the nucleon axial and induced pseudo-scalar form factors using an ensemble of two degenerate twisted mass clover-improved fermions generated at the physical value of the pion mass. We evaluate the is...
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Large center vortices and confinement in 3D Z(2) gauge theory: We study the role of large clusters of center vortices in producing confinement in 3D Z(2) gauge theory. First, we modify each configuration of a Monte Carlo-generated ensemble in the confined phase by removing the largest cluster of center vortices, and sh...
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