Chiral Defect Fermions and the Layered Phase

TL;DR

This paper investigates chiral defect fermions in a 4+1 dimensional lattice, revealing how their localized chiral modes depend on coupling strength and identifying a layered phase where the theory becomes vector-like across layers.

Contribution

It introduces a mean field analysis of chiral defect fermions, showing the conditions for localized modes and the emergence of a layered phase in lattice gauge theories.

Findings

Localized chiral modes exist at weak coupling

Chiral modes are lost at strong coupling in the fifth dimension

A layered phase with vector-like behavior appears at certain couplings

Abstract

Chiral defect fermions on the lattice in 4+1 dimensions are analyzed using mean field theory. The fermion propagator has a localized chiral mode in weak coupling but loses it when the coupling in the unphysical fifth direction becomes too large. A layered phase \`a la Fu-Nielsen appears where the theory is vector-like in every layer.