Accelerated Overlap Fermions

Abstract

Numerical evaluation of the overlap Dirac operator is difficult since it contains the sign function $\epsilon (H_w)$ of the Hermitian Wilson-Dirac operator $H_w$ with a negative mass term. The problems are due to $H_w$ having very small eigenvalues on the equilibrium background configurations generated in current day Monte Carlo simulations. Since these are a consequence of the lattice discretisation and do not occur in the continuum version of the operator, we investigate in this paper to what extent the numerical evaluation of the overlap can be accelerated by making the Wilson-Dirac operator more continuum-like. Specifically, we study the effect of including the clover term in the Wilson-Dirac operator and smearing the link variables in the irrelevant terms. In doing so, we have obtained a factor of two speedup by moving from the Wilson action to a FLIC (Fat Link Irrelevant Clover) action as the overlap kernel.

15 pages, 6 figures; V2 contains major revision of the introduction and motivation sections. Conclusion and results unchanged v2.1: formatting change

References in corpus (9)

• Hadron Masses From Novel Fat-Link Fermion Actions
• The U_A(1) Problem on the Lattice with Ginsparg-Wilson Fermions
• Improved Smoothing Algorithms for Lattice Gauge Theory
• Chiral Properties of Pseudoscalar Mesons on a Quenched $20^4$ Lattice with Overlap Fermions
• Are Topological Charge Fluctuations in QCD Instanton Dominated?
• The Index of a Ginsparg-Wilson Dirac operator
• First results from a parametrized Fixed-Point QCD action
• Perturbation Calculation of the Axial Anomaly of a Ginsparg-Wilson lattice Dirac operator
• Fast evaluation and locality of overlap fermions

Cited by in corpus (27)

• Physics issues in simulations with dynamical overlap fermions
• Unquenching effects in the quark and gluon propagator
• Hybrid Monte Carlo with Fat Link Fermion Actions
• Filtered overlap: speedup, locality, kernel non-normality and Z_A~1
• Scaling of FLIC Fermions
• Connection between centre vortices and instantons through gauge-field smoothing
• Locality and topology with fat link overlap actions
• Convergence Rate and Locality of Improved Overlap Fermions
• Scaling behavior of the overlap quark propagator in Landau gauge
• Overlap Hypercube Fermions in QCD Simulations Near the Chiral Limit
• Improved chiral properties of FLIC fermions
• Centre vortex removal restores chiral symmetry
• Spin 3/2 Pentaquark Resonance Signature in Lattice QCD
• Exploring Topology Conserving Gauge Actions for Lattice QCD
• The FLIC Overlap Quark Propagator
• FLIC Fermions and Hadron Phenomenology
• Wilson mass dependence of the overlap topological charge density
• Quark Propagation in the Instantons of Lattice QCD
• Electromagnetic Form Factors with FLIC fermions
• Role of chiral symmetry in the nucleon excitation spectrum
• Overlap quark propagator near the physical pion mass
• Numerical indication that center vortices drive dynamical mass generation in QCD
• Physics prospects of UV-filtered overlap quarks
• Smoothing algorithms for projected center-vortex gauge fields
• Hadron Properties with FLIC Fermions
• Stout-link smearing in lattice fermion actions
• Light Quark Simulations With FLIC Fermions