Gap Domain Wall Fermions

TL;DR

This paper shows that adding two Wilson fermions to the Domain Wall Fermion action significantly improves chiral symmetry properties at moderate lattice spacings in QCD simulations, reducing residual mass and enhancing topological activity.

Contribution

The study introduces a novel modification to DWF by adding Wilson fermions, improving chiral properties and eigenvalue spectrum in quenched QCD simulations.

Findings

Eigenvalue spectrum develops a substantial gap

Residual mass decreases appreciably

Topology changing remains active

Abstract

I demonstrate that the chiral properties of Domain Wall Fermions (DWF) in the large to intermediate lattice spacing regime of QCD, 1 to 2 GeV, are significantly improved by adding to the action two standard Wilson fermions with supercritical mass equal to the negative DWF five dimensional mass. Using quenched DWF simulations I show that the eigenvalue spectrum of the transfer matrix Hamiltonian develops a substantial gap and that the residual mass decreases appreciatively. Furthermore, I confirm that topology changing remains active and that the hadron spectrum of the added Wilson fermions is above the lattice cutoff and therefore is irrelevant. I argue that this result should also hold for dynamical DWF and furthermore that it should improve the chiral properties of related fermion methods.