New Domain-Wall Fermion Actions

TL;DR

This paper introduces new domain-wall fermion actions with extended couplings that significantly improve the decay rate of the wave function, potentially enhancing chiral symmetry preservation at coarser lattice spacings.

Contribution

The authors propose novel domain-wall actions with beyond-nearest neighbor couplings, leading to faster wave function decay and improved chiral properties in lattice QCD simulations.

Findings

One-loop wave function decay rate matches the slowest tree-level rate for any momentum.

New actions exhibit much faster wave function decay.

Potential to maintain chiral symmetry at larger lattice spacings.

Abstract

In perturbation theory, the wave function of domain-wall quarks decreases exponentially with the fifth coordinate. We show that, regardless of the quark's own momentum, the fall-off rate of the one-loop wave function is equal to the slowest rate encountered at tree-level for any lattice four-momentum. We propose new domain-wall actions involving beyond-nearest neighbor couplings in the four physical dimensions, for which the perturbative wave function decreases much faster. It is hoped that the new actions may preserve the good chiral properties of domain-wall fermions up to larger values of the lattice spacing.