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Matrix elements relevant for Delta I=1/2 rule and epsilon-prime from Lattice QCD with staggered fermions: We perform a study of matrix elements relevant for the Delta I=1/2 rule and the direct CP-violation parameter epsilon-prime from first principles by computer simulation in Lattice QCD. We use staggered (Kogut-Sus...
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Neutron electric dipole moment on the lattice: We carry out a feasibility study toward a lattice QCD calculation of the neutron electric dipole moment (NEDM) in the presence of the $\theta$ term using two different approaches. In the first method, we calculate the CP-odd electromagnetic form factor $F_3$, which becomes...
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Determination of $s$- and $p$-wave $I=1/2$ $Kπ$ scattering amplitudes in $N_{\mathrm{f}}=2+1$ lattice QCD: The elastic $I=1/2$, $s$- and $p$-wave kaon-pion scattering amplitudes are calculated using a single ensemble of anisotropic lattice QCD gauge field configurations with $N_{\mathrm{f}} = 2+1$ flavors of dynamica...
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Correlation functions in lattice formulations of quantum gravity: We compare different models of a quantum theory of four-dimensional lattice gravity based on Regge's original proposal. From Monte Carlo simulations we calculate two-point functions between geometrical quantities and estimate the masses of the correspond...
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The topological susceptibility in finite temperature QCD and axion cosmology: We study the topological susceptibility in 2+1 flavor QCD above the chiral crossover transition temperature using Highly Improved Staggered Quark action and several lattice spacings, corresponding to temporal extent of the lattice, $N_\tau=...
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Inclusive hadronic decay rate of the $τ$ lepton from lattice QCD: Inclusive hadronic decays of the $\tau$ lepton are very interesting from the phenomenological point of view since they give access to the CKM matrix elements $V_{ud}$ and $V_{us}$. In this paper, for the first time, by employing the HLT method for hadron...
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Exploring the HMC trajectory-length dependence of autocorrelation times in lattice QCD: We study autocorrelation times of physical observables in lattice QCD as a function of the molecular dynamics trajectory length in the hybrid Monte-Carlo algorithm. In an interval of trajectory lengths where energy and reversibili...
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Strong isospin violation and chiral logarithms in the baryon spectrum: We present a precise lattice QCD calculation of the contribution to the neutron-proton mass splitting arising from strong isospin breaking, $m_n-m_p|_{QCD}=2.32\pm0.17$ MeV. We also determine $m_{\Xi^-} - m_{\Xi^0}|_{QCD} = 5.44\pm0.31$ MeV. The cal...
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Disconnected Quark Loop Contributions to Nucleon Structure: We calculate the disconnected contribution to isoscalar nucleon charges for scalar, axial and tensor channels of light and strange quarks. The calculation has been done with the Clover valence quarks on the MILC $N_f=2+1+1$ HISQ lattices whose light quark mass...
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Recent progress in applying lattice QCD to kaon physics: Standard lattice calculations in kaon physics are based on the evaluation of matrix elements of local operators between two single-hadron states or a single-hadron state and the vacuum. Recent progress in lattice QCD has gone beyond these standard observables. I ...
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$m_c$ (and $m_b$) from lattice QCD: Quark mass determinations based on lattice QCD simulations have continued to make strides in recent years. Here I review that progress with a focus on developments computing the charm (and bottom) quark masses since the 2015 edition of CHARM. These advances have resulted in groups no...
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NRQCD and Static Systems -- A General Variational Approach: We present initial results from Monte Carlo simulations of NRQCD-light, static-light, and NRQCD-NRQCD mesons, using a variational technique (MOST), as part of our ongoing calculation of the $f_{B}$ decay constant. The basis states for the variational calculati...
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Chern-Simons term in the 4-dimensional SU(2) Higgs Model: Using Seiberg's definition for the geometric charge in SU(2) lattice gauge theory, we have managed to apply it also to the Chern-Simons term. We checked the periodic structure and determined the Chern-Simons density on small lattices $L^4$ and $L^3 \times 2,\, 4...
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Meron-Cluster Solution of Fermion and Other Sign Problems: Numerical simulations of numerous quantum systems suffer from the notorious sign problem. Important examples include QCD and other field theories at non-zero chemical potential, at non-zero vacuum angle, or with an odd number of flavors, as well as the Hubbard ...
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High-Precision c and b Masses, and QCD Coupling from Current-Current Correlators in Lattice and Continuum QCD: We extend our earlier lattice-QCD analysis of heavy-quark correlators to smaller lattice spacings and larger masses to obtain new values for the c mass and QCD coupling, and, for the first time, values for t...
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Exploring quark transverse momentum distributions with lattice QCD: We discuss in detail a method to study transverse momentum dependent parton distribution functions (TMDs) using lattice QCD. To develop the formalism and to obtain first numerical results, we directly implement a bi-local quark-quark operator connected...
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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 the O(N) sigma model at large N is reviewed. Practically exact nonperturbative results become available for both finite and vanishing lattice spacing. We use them as a testbed to investigate s...
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Rare $B$ decays using lattice QCD form factors: In this write-up we review and update our recent lattice QCD calculation of $B \to K^*$, $B_s \to \phi$, and $B_s \to K^*$ form factors [arXiv:1310.3722]. These unquenched calculations, performed in the low-recoil kinematic regime, provide a significant improvement over t...
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Toward dense QCD in quantum computers: Lattice QCD at nonzero baryon density is a big challenge in hadron physics. In this presentation, I discuss the quantum computation of lattice gauge theory at nonzero density. I show some benchmark results of the Schwinger model obtained by the quantum adiabatic algorithm and the ...
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The lower moments of nucleon structure functions in lattice QCD with physical quark masses: We present results for the nucleon structure functions and form factors obtained from 2+1 flavor lattice QCD with physical light quark masses ($m_{\pi}=135$ MeV) in a large spatial extent of about 10 fm. Our calculations are p...
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The dual sector of the φ^4 Theory in 4D: The one-component $\lambda\phi^4$ theory in four dimensions in the spontaneously broken symmetry phase has a non-trivial, non-perturbative sector which can be studied by means of a duality transformation of its Ising limit. Duality maps this theory to a model of interacting memb...
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Color Dynamics in External Fields: We investigate the vacuum dynamics of U(1), SU(2), and SU(3) lattice gauge theories in presence of external (chromo)magnetic fields, both in (3+1) and (2+1) dimensions. We find that the critical coupling for the phase transition in compact U(1) gauge theory is independent of the stren...
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Lattice QCD determination of states with spin 5/2 or higher in the spectrum of nucleons: Energies for excited isospin 1/2 states that include the nucleon are computed using quenched, anisotropic lattices. Baryon interpolating field operators that are used include nonlocal operators that provide $G_2$ irreducible repr...
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Machine Learning Trivializing Maps: A First Step Towards Understanding How Flow-Based Samplers Scale Up: A trivializing map is a field transformation whose Jacobian determinant exactly cancels the interaction terms in the action, providing a representation of the theory in terms of a deterministic transformation of a...
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Rare decay B -> K ll form factors from lattice QCD: We calculate, for the first time using unquenched lattice QCD, form factors for the rare decay B -> Kll in and beyond the Standard Model. Our lattice QCD calculation utilizes a nonrelativistic QCD formulation for the b valence quarks, the highly improved staggered qua...
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A complete non-perturbative renormalization prescription for quasi-PDFs: In this work we present, for the first time, the non-perturbative renormalization for the unpolarized, helicity and transversity quasi-PDFs, in an RI' scheme. The proposed prescription addresses simultaneously all aspects of renormalization: logar...
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Excited states in the full QCD hadron spectrum on a $16^3 \times 40$ lattice: We report the hadron mass spectrum obtained on a $16^3 \times 40$ lattice at $\beta = 5.7$ using two flavors of staggered fermions with $m a = 0.01$. We calculate the masses of excited states that have the same quantum numbers as the $\pi$,...
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Renormalisation of lattice currents and the calculation of decay constants for dynamical staggered fermions: A numerical calculation of the lattice staggered renormalisation constants at $\beta = 5.35$, $m = 0.01$ is presented. It is seen that there are considerable non-perturbative effects present. As an application...
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Quenched QCD at finite temperature with chiral Fermions: We study physics at temperatures just above the QCD phase transition (Tc) using chiral (overlap) Fermions in the quenched approximation of lattice QCD. Exact zero modes of the overlap Dirac operator are localized and their frequency of occurrence drops with tempe...
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A method to measure the antikaon-nucleon scattering length in lattice QCD: We propose a method to determine the isoscalar \bar K N scattering length on the lattice. Our method represents the generalization of L\"uscher's approach in the presence of inelastic channels (complex scattering length). In addition, the prop...
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Light hadron masses with 4-GeV cutoff and L=2.4fm: We discuss preliminary results from our quenched light hadron mass calculation on a $48^3 \times 64$ lattice at the coupling of $\beta = 6.5$. Staggered quarks with masses of $m_q = 0.01, 0.005, 0.0025$ and $0.00125$ are used.
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Exploring a hidden symmetry with electrically charged quarks: It is usual to study confinement via quantum chromodynamics (QCD) alone. The deconfinement transition of the pure gauge theory (i.e. with static quarks) is then characterized by the breaking of center symmetry. Center vortices offer an intuitive and quantita...
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Continuum limit of the leading order HQET form factor in $B_s \to K\ellν$ decays: We discuss the computation of form factors for semi-leptonic decays of $\rm B$-, $\rm B_s$- mesons in lattice QCD. Considering in particular the example of the static $\rm B_s$ form factors we demonstrate that after non-perturbative ren...
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Non-Perturbative Gauge-Higgs Unification in Five Dimensions: We study the phase diagram and mass spectrum of an $SU(2)$ Gauge-Higgs Unification scenario on a five-dimensional orbifold.We observe spontaneous symmetry breaking within the Higgs phase of the theory and, in the vicinity of a newly discovered phase, we find ...
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Numerical methods for the sign problem in Lattice Field Theory: The great majority of algorithms employed in the study of lattice field theory are based on Monte Carlo's importance sampling method, i.e. on probability interpretation of the Boltzmann weight. Unfortunately in many theories of interest one cannot associat...
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Lattice Study of the Extent of the Conformal Window in Two-Color Yang-Mills Theory: We perform a lattice calculation of the Schr\"odinger functional running coupling in SU(2) Yang-Mills theory with six massless Wilson fermions in the fundamental representation. The aim of this work is to determine whether the above t...
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Semileptonic form factor ratio B_s->D_s/B->D and its application to BR(B^0_s->μ^+μ^-): We present a (2+1)-flavor lattice QCD calculation of the form factor ratio between the semileptonic decays $\bar{B}^0_s \to D^+_sl^-\bar{\nu} $ and $\bar{B}^0 \to D^+l^-\bar{\nu} $. This ratio is an important theoretical input to t...
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Thermodynamical quantities for overlap fermions with chemical potential: Recently a formulation of overlap fermions at finite density based on an analytic continuation of the sign function was proposed. We study this proposal by analyzing the energy and number densities for free fermions as a function of the chemical p...
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Controlling Excited-State Contributions with Distillation in Lattice QCD Calculations of Nucleon Isovector Charges $g_S^{u-d}$, $g_A^{u-d}$, $g_T^{u-d}$: We investigate the application of the distillation smearing approach, and the use of the variational method with an extended basis of operators facilitated by thi...
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Eigenvalues and Eigenvectors of the Staggered Dirac Operator at Finite Temperature: We examine the eigenvalues and eigenvectors of the staggered Dirac operator on thermal ensembles created in QCD with two flavours of staggered quarks. We see that across the phase transition a gap opens in the spectrum. For finite vol...
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Monopole and instanton effects on connected and disconnected correlations for scalar density: This study investigates the effects on the connected and disconnected correlations for the scalar density that are induced by created monopoles and instantons in the QCD vacuum. To reveal the effects, we add a monopole and a...
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Critical point phase transition for finite temperature 3-flavor QCD with 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 focus on locating the critical point which separates crossover and first order phase transition reg...
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Chiral condensate, susceptibilities, critical coupling and indices in QED$_4$: We measure chiral susceptibilities in the Coulomb phase of noncompact QED$_4$ in $8^4, 10^4$ and $12^4$ lattices. The MFA approach allows simulations in the chiral limit which are therefore free from arbitrary mass extrapolations. Using th...
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Quark number susceptibility at high temperature: We use three dimensional reduced effective field theory (EQCD) and lattice calculations to determine the quark number susceptibility of QCD at high temperature. We find our results to agree well with known perturbative expansion as well as with other lattice data.
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Angular momentum content of the rho-meson in lattice QCD: The variational method allows one to study the mixing of interpolators with different chiral transformation properties in the non-perturbatively determined physical state. It is then possible to define and calculate in a gauge-invariant manner the chiral as well...
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The Kaon B-parameter in Mixed Action Chiral Perturbation Theory: We calculate the kaon B-parameter, B_K, in chiral perturbation theory for a partially quenched, mixed action theory with Ginsparg-Wilson valence quarks and staggered sea quarks. We find that the resulting expression is similar to that in the continuum, an...
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Moments of generalized parton distributions and quark angular momentum of the nucleon: The internal structure of hadrons is important for a variety of topics, including the hadron form factors, proton spin and spin asymmetry in polarized proton scattering. For a systematic study generalized parton distributions (GP...
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Fermions obstruct dimensional reduction in hot QCD: We have studied, for the first time, screening masses obtained from glueball-like correlators in Quantum Chromodynamics with four light dynamical flavours of quarks in the temperature range 1.5T_c < T < 3T_c, where T_c is the temperature at which the chiral transition...
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Mean-Field Gauge Interactions in Five Dimensions II. The Orbifold: We study Gauge-Higgs Unification in five dimensions on the lattice by means of the mean-field expansion. We formulate it for the case of an SU(2) pure gauge theory and orbifold boundary conditions along the extra dimension, which explicitly break the ga...
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Probing the Region of Massless Quarks in Quenched Lattice QCD using Wilson Fermions: We study the spectrum of $H(m)=\gamma_5 W(-m)$ with $W(m)$ being the Wilson-Dirac operator on the lattice with bare mass equal to $m$. The background gauge fields are generated using the SU(3) Wilson action at $\beta=5.7$ on an $8^3\...
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Spectral Analysis of Causal Dynamical Triangulations via Finite Element Method: We examine the dual graph representation of simplicial manifolds in Causal Dynamical Triangulations (CDT) as a mean to build observables, and propose a new representation based on the Finite Element Methods (FEM). In particular, with the ...
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Higgs mechanism in five-dimensional gauge theories: Lattice simulations of five-dimensional gauge theories on an orbifold revealed that there is spontaneous symmetry breaking. Some of the extra-dimensional components of the gauge field play the role of a Higgs field and some of the four-dimensional components become ma...
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Nuclear Physics Review: Anchoring low-energy nuclear physics to the fundamental theory of strong interactions remains an outstanding challenge. I review the current progress and challenges of the endeavor to use lattice QCD to bridge this connection. This is a particularly exciting time for this line of research as dem...
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The three-loop beta function in SU(N) lattice gauge theories: We calculate the third coefficient of the lattice $\beta$ function in pure Yang-Mills theory. We make use of a computer code for solving perturbation theory analytically on the lattice. We compute the divergent integrals by using a method based on a Taylor e...
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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 gravity is significantly different from the ground states to the well-known vacua in QED, QCD, et cetera. In the case of the lattice Euclidean quantum gravity, the long-wavel...
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Composite flavor-singlet scalar in twelve-flavor QCD: We report the calculation of the flavor-singlet scalar in the SU(3) gauge theory with the degenerate twelve fermions in the fundamental representation using a HISQ-type action at a fixed $\beta$. In order to reduce the large statistical error coming from the vacuum-...
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Landau gauge gluon and ghost propagators from two-flavor lattice QCD at T > 0: In this contribution we extend our unquenched computation of the Landau gauge gluon and ghost propagators in lattice QCD at non-zero temperature. The study was aimed at providing input for investigations employing continuum functional meth...
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A numerical and theoretical study of multilevel performance for two-point correlator calculations: An investigation of the performance of the multilevel algorithm in the approach to criticality has been undertaken using the Ising model, performing simulations across a range of temperatures. Numerical results show tha...
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SU(4) lattice gauge theory with decuplet fermions: Schrödinger functional analysis: We complete a program of study of SU(N) gauge theories coupled to two flavors of fermions in the two-index symmetric representation by performing numerical simulations in SU(4). The beta function, defined and calculated via the Schr\"...
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Irregular parameter dependence of numerical results in tensor renormalization group analysis: We study the parameter dependence of numerical results obtained by the tensor renormalization group. We often observe an irregular behavior as the parameters are varied with the method, which makes it difficult to perform th...
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Quantum Field Theories with Tensor Renormalization Group: We report recent progress on the application of the tensor renormalization group (TRG) to quantum field theories pursued by the Tsukuba group. We explain how to treat the scalar, fermion, and gauge theories with the TRG method presenting the results for the phas...
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Lattice Gauge Fixing, Gribov Copies and BRST Symmetry: We show that a modification of the BRST lattice quantization allows to circumvent an old paradox, formulated by Neuberger, related to lattice Gribov copies and non-perturbative BRST invariance. In the continuum limit the usual BRST formulation is recovered.
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Multi-block/multi-core SSOR preconditioner for the QCD quark solver for K computer: We study the algorithmic optimization and performance tuning of the Lattice QCD clover-fermion solver for the K computer. We implement the L\"uscher's SAP preconditioner with sub-blocking in which the lattice block in a node is furthe...
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Light hadron masses with a tadpole-improved next-nearest-neighbour lattice fermion action: Calculations of hadron masses are done in quenched approximation using gauge field and fermion actions which are both corrected for discretization errors to $O(a^2)$ at the classical level and which contain tadpole improvement ...
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Perfect Lattice Actions for the Gross-Neveu Model: We apply the method of Hasenfratz and Niedermayer to analytically construct perfect lattice actions for the Gross--Neveu model. In the large $N$ limit these actions display an exactly perfect scaling, i.e. cut-off artifacts are completely eliminated even at arbitrarily...
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Asymptotic scaling in the two-dimensional $SU(3)$ $σ$-model at correlation length $4 \times 10^5$: We carry out a high-precision simulation of the two-dimensional $SU(3)$ principal chiral model at correlation lengths $\xi$ up to $\approx\! 4 \times 10^5$, using a multi-grid Monte Carlo (MGMC) algorithm. We extrapolat...
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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 treatments for the heavy quark. For B mesons, we determined fB, fBs, and fBs/fB with NRQCD bottom quarks. We then combined the ratio fBs/fB and another very precise determination ...
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Status of the Finite Temperature Electroweak Phase Transition on the Lattice: I review the status of non-perturbative investigations of the finite temperature electroweak phase transition by means of lattice simulations.
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Leading Isospin Breaking effects in nucleon and $Δ$ masses: We present a lattice calculation of the leading corrections to the masses of nucleons and $\Delta$ resonances. These are obtained in QCD+QED at $1$st order in the Isospin Breaking parameters $\alpha_{EM}$, the electromagnetic coupling, and $\frac{{\hat{m}}_d -...
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Form factors for semi-leptonic B decays: We report on form factors for the B->K l^+ l^- semi-leptonic decay process. We use several lattice spacings from a=0.12 fm down to 0.06 fm and a variety of dynamical quark masses with 2+1 flavors of asqtad quarks provided by the MILC Collaboration. These ensembles allow good con...
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Strong-coupling expansion of lattice O(N) sigma models: We report progress in the computation and analysis of strong-coupling series of two- and three-dimensional ${\rm O}(N)$ $\sigma$ models. We show that, through a combination of long strong-coupling series and judicious choice of observables, one can compute continu...
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Critical exponents of a three dimensional O(4) spin model: By Monte Carlo simulation we study the critical exponents governing the transition of the three-dimensional classical O(4) Heisenberg model, which is considered to be in the same universality class as the finite-temperature QCD with massless two flavors. We use...
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An ideal toy model for confining, walking and conformal gauge theories: the O(3) sigma model with theta-term: A toy model is proposed for four dimensional non-abelian gauge theories coupled to a large number of fermionic degrees of freedom. As the number of flavors is varied the gauge theory may be confining, walking...
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A lattice calculation of the pion form factor with Ginsparg-Wilson-type fermions: Results for Monte Carlo calculations of the electromagnetic vector and scalar form factors of the pion in a quenched simulation are presented. We work with two different lattice volumes up to a spatial size of 2.4 fm at a lattice spacin...
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'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 decay amplitude by using numerical simulations of QCD on the lattice. From our study with Nf=2 dynamical light quarks, and by employing the maximally twisted Wilson quark actio...
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A direct relation between confinement and chiral symmetry breaking in temporally odd-number lattice QCD: In the lattice QCD formalism, we derive a gauge-invariant analytical relation connecting the Polyakov loop and the Dirac modes on a temporally odd-number lattice, where the temporal lattice size is odd, with the n...
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Physics from the lattice: glueballs in QCD; topology; SU(N) for all N: Lectures given at the Isaac Newton Institute, NATO-ASI School on "Confinement, Duality and Non-Perturbative Aspects of QCD", 23 June - 4 July, 1997.
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Perturbation theory predictions and Monte Carlo simulations for the 2-d O(n) non-linear sigma-model: By using the results of a high-statistics (O(10^7) measurements) Monte Carlo simulation we test several predictions of perturbation theory on the O(n) non-linear sigma-model in 2 dimensions. We study the O(3) and O(8)...
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A simple approach towards the sign problem using path optimisation: We suggest an approach for simulating theories with a sign problem that relies on optimisation of complex integration contours that are not restricted to lie along Lefschetz thimbles. To that end we consider the toy model of a one-dimensional Bose gas ...
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Colorful plane vortices and Chiral Symmetry Breaking in $SU(2)$ Lattice Gauge Theory: We investigate plane vortices with color structure. The topological charge and gauge action of such colorful plane vortices are studied in the continuum and on the lattice. These configurations are vacuum to vacuum transitions chang...
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Anomalous Fermion Number Non-Conservation on the Lattice: The anomaly for the fermion number current is calculated on the lattice in a simple prototype model with an even number of fermion doublets.
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The Renormalization Group and Dynamical Triangulations: A block spin renormalization group approach is introduced which can be applied to dynamical triangulations in any dimension.
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Trivializing maps, the Wilson flow and the HMC algorithm: In lattice gauge theory, there exist field transformations that map the theory to the trivial one, where the basic field variables are completely decoupled from one another. Such maps can be constructed systematically by integrating certain flow equations in fie...
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The static energy of a quark-antiquark pair from Laplacian eigenmodes: We test a method for computing the static quark-antiquark potential in lattice QCD, which is not based on Wilson loops, but where the trial states are formed by eigenvector components of the covariant lattice Laplace operator. The runtime of this me...
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Static quark anti-quark interactions at non-zero temperature from lattice QCD: We present results on the in-medium interactions of static quark anti-quark pairs using realistic 2+1 HISQ flavor lattice QCD. Focus is put on the extraction of spectral information from Wilson line correlators in Coulomb gauge using four ...
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Perturbative calculations for the HISQ action: the gluon action at $O(N_fα_sa^2)$: We present a new (and general) algorithm for deriving lattice Feynman rules which is capable of handling actions as complex as the Highly Improved Staggered Quark (HISQ) action. This enables us to perform a perturbative calculation of ...
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A new fermion Hamiltonian for lattice gauge theory: We formulate Hamiltonian vector-like lattice gauge theory using the overlap formula for the spatial fermionic part, $H_f$. We define a chiral charge, $Q_5$ which commutes with $H_f$, but not with the electric field term. There is an interesting relation between the ch...
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Lattice Models of Quantum Gravity: Standard Regge Calculus provides an interesting method to explore quantum gravity in a non-perturbative fashion but turns out to be a CPU-time demanding enterprise. One therefore seeks for suitable approximations which retain most of its universal features. The $Z_2$-Regge model could...
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Hadronic vacuum polarization with C* boundary conditions: We present a progress report on the calculation of the connected hadronic contribution to the muon g-2 with C* boundary conditions. For that purpose we use a QCD gauge ensemble with 3+1 flavors and two QCD+QED gauge ensembles with 1+2+1 flavors of dynamical quar...
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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 x 64, L_s=32 dynamical lattices with 2+1 flavors of domain wall fermions using the DSDR and Iwasaki gauge action. The calculation is performed with a single pion mass (m_pi=141...
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Colorful vortex intersections in SU(2) lattice gauge theory and their influencs on chiral properties: We introduce topological non-trivial colorful regions around intersection points of two perpendicular vortex pairs and investigate their influence on topological charge density and eigenmodes of the Dirac operator. W...
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First experience with classical-statistical real-time simulations of anomalous transport with overlap fermions: We present first results of classical-statistical real-time simulations of anomalous transport phenomena with overlap fermions. We find that even on small lattices overlap fermions reproduce the real-time a...
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Magnetic properties of the nucleon in a uniform background field: We present results for the magnetic moment and magnetic polarisability of the neutron and the magnetic moment of the proton. These results are calculated using the uniform background field method on 32^3 x 64 dynamical QCD lattices provided by the PACS-C...
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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 is the Ginzburg-Landau theory of superconductivity. We confirm that for small scalar self-coupling the transition is of first order. For large scalar self-coupling the transition ceas...
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Correlated Dirac Eigenvalues and Axial Anomaly in Chiral Symmetric QCD: We investigate the Dirac eigenvalue spectrum ($\rho(\lambda,m_l)$) to study the microscopic origin of axial anomaly in high temperature phase of QCD. We propose novel relations between the derivatives ($\partial^n \rho(\lambda,m_l)/\partial m_l^n$)...
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Monte Carlo approach to the string/M-theory: It has long been conjectured that certain supersymmetric Yang-Mills (SYM) theories provide us with nonperturbative formulations of the string/M-theory. Although the supersymmetry (SUSY) on lattice is notoriously difficult in general, for a class of theories important for the...
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Asymptotic scaling from strong coupling: Strong-coupling analysis of two-dimensional chiral models, extended to 15th order, allows for the identification of a scaling region where known continuum results are reproduced with great accuracy, and asymptotic scaling predictions are fulfilled. The properties of the large-$N...
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Polyakov loops and spectral properties of the staggered Dirac operator: We study the spectrum of the staggered Dirac operator in SU(2) gauge fields close to the free limit, for both the fundamental and the adjoint representation. Numerically we find a characteristic cluster structure with spacings of adjacent levels se...
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Uses of Effective Field Theory in Lattice QCD: Several physical problems in particle physics, nuclear physics, and astrophysics require information from non-perturbative QCD to gain a full understanding. In some cases the most reliable technique for quantitative results is to carry out large-scale numerical calculation...
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A microscopic semiclassical confining field equation for $U(1)$ lattice gauge theory in 2+1 dimensions: We present a semiclassical nonlinear field equation for the confining field in 2+1--dimensional $U(1)$ lattice gauge theory (compact QED). The equation is derived directly from the underlying microscopic quantum Ha...
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