Convergence Rate and Locality of Improved Overlap Fermions

Abstract

We construct new Ginsparg-Wilson fermions for QCD by inserting an approximately chiral Dirac operator - which involves ingredients of a perfect action - into the overlap formula. This accelerates the convergence of the overlap Dirac operator by a factor of 5 compared to the standard construction, which inserts the Wilson fermion as a point of departure. Taking into account the effort for treating the improved fermion, we are left with an total computational overhead of about a factor 3. This remaining factor is likely to be compensated by other virtues; here we show that the level of locality is clearly improved, so that the exponent of the correlation decay is doubled. We also show that approximate rotation invariance is drastically improved, but a careful scaling test has to be postponed.

33 pages, 16 figures, a Section on approximate rotation symmetry is added

References in corpus (10)

• Low-lying fermion modes, topology and light hadrons in quenched QCD
• Light Quark Masses with Overlap Fermions in Quenched QCD
• Overlap Quark Propagator in Landau Gauge
• Finite-size Scaling of Meson Propagators
• Accelerated Overlap Fermions
• Chiral measurements with the Fixed-Point Dirac operator and construction of chiral currents
• First results from a parametrized Fixed-Point QCD action
• A comparative study of numerical methods for the overlap Dirac operator--a status report
• Classically Perfect Gauge Actions on Anisotropic Lattices
• Fast evaluation and locality of overlap fermions

Cited by in corpus (28)

• Numerical techniques for lattice QCD in the $\epsilon$--regime
• Quenched spectroscopy with fixed-point and chirally improved fermions
• Physics issues in simulations with dynamical overlap fermions
• Axial Correlation Functions in the epsilon-Regime: a Numerical Study with Overlap Fermions
• Hybrid Monte Carlo with Fat Link Fermion Actions
• Spectral Properties of the Overlap Dirac Operator in QCD
• Filtered overlap: speedup, locality, kernel non-normality and Z_A~1
• Locality and topology with fat link overlap actions
• One loop matching coefficients for a variant overlap action--and some of its simpler relatives
• Brillouin improvement for Wilson fermions
• Overlap Hypercube Fermions in QCD Simulations Near the Chiral Limit
• Probing the fuzzy sphere regularisation in simulations of the 3d λϕ^4 model
• The FLIC Overlap Quark Propagator
• Exploring Topology Conserving Gauge Actions for Lattice QCD
• A Numerical Study of the 2-Flavour Schwinger Model with Dynamical Overlap Hypercube Fermions
• Wilson mass dependence of the overlap topological charge density
• Axial Anomaly and Index of the Overlap Hypercube Operator
• Role of chiral symmetry in the nucleon excitation spectrum
• Optimised Dirac Operators on the Lattice: Construction, Properties and Applications
• Overlap quark propagator near the physical pion mass
• Dynamical FLIC Fermions
• Features of a 2d Gauge Theory with Vanishing Chiral Condensate
• Numerical indication that center vortices drive dynamical mass generation in QCD
• New solutions to the Ginsparg-Wilson equation
• Improving the locality of the overlap Dirac operator via approximate solutions of the Ginsparg-Wilson relation
• Overlap Hypercube Fermions in QCD
• Stout-link smearing in lattice fermion actions
• Dynamical fat link fermions