Strong coupling analysis of Aoki phase in Staggered-Wilson fermions

TL;DR

This paper analyzes the phase structure of lattice QCD with staggered-Wilson fermions at strong coupling, revealing a parity-broken phase and conditions for chiral limit tuning.

Contribution

It provides a strong-coupling effective potential analysis showing the existence of a parity-broken phase and chiral symmetry restoration in staggered-Wilson fermions.

Findings

Nonzero pion condensate indicating parity breaking

Massless pions near the phase boundary

Chiral limit achievable by tuning the mass parameter

Abstract

We study strong-coupling lattice QCD with staggered-Wilson fermions, with an emphasis on the possibility of spontaneous parity breaking. We perform effective potential analysis in the strong-coupling limit. From gap equations we find the pion condensate becomes nonzero in some range of a mass parameter, which indicates the existence of the parity-broken phase. We also find massless pions and PCAC relations around the second-order phase boundary. These results suggest that we can take the chiral limit by tuning a mass parameter in lattice QCD with staggered-Wilson fermions as with the Wilson fermion.