Domain-Wall Fermions at Strong Coupling

TL;DR

This paper reviews efforts to modify domain-wall fermion formulations to maintain their effectiveness at strong gauge couplings where traditional methods face significant challenges due to increased chiral symmetry breaking.

Contribution

The authors explore modifications to gauge and fermion actions to improve the reliability of domain-wall fermions at strong coupling regimes.

Findings

Identified issues with DWF at couplings where $a^{-1}<2$ GeV.

Reviewed potential modifications to improve DWF performance.

Discussed the relation to the Aoki phase in strong coupling regimes.

Abstract

The DWF formulation becomes increasingly problematic at gauge couplings for which $a^{-1}<2$ GeV, where the roughness of the gauge field leads to increased explicit chiral symmetry breaking ($\mres$). This problem becomes especially severe for sufficiently strong coupling where the underlying 4-dimensional Wilson theory is in the Aoki phase. We review our attempts to find a suitable modification of the gauge and/or the fermion action which would allow the DWF method to work reliably at stronger coupling.