Search for a continuum limit of the PMS phase

TL;DR

This paper investigates the existence of a continuum limit of the PMS phase in a 4D four-fermion model, extending previous 3D studies, and finds evidence for an intermediate broken phase with precise phase boundary measurements.

Contribution

It extends the 3D four-fermion model study to 4D, discovering an intermediate broken phase and accurately determining phase boundaries, suggesting a new fermion mass generation mechanism.

Findings

Evidence for an intermediate spontaneously broken phase in 4D

Accurate computation of phase boundaries

Small width of the intermediate region in coupling space

Abstract

Previous studies of a simple four-fermion model with staggered fermions in 3D have shown the existence of an exotic quantum critical point, where one may be able to define a continuum limit of the Paramagnetic Strong Phase (or the PMS phase). We believe the existence of the critical point suggests a new mechanism for generating fermion masses. In this work we begin the search for this quantum critical point in 4D by extending the 3D model to 4D. Unlike in 3D, now we do find evidence for an intermediate spontaneously broken phase (FM phase) and are able compute the phase boundaries accurately. In terms of the bare coupling, the width of the intermediate region appears to be quite small.