Domain Walls and Metastable Vacua in Hot Orientifold Field Theories

TL;DR

This paper investigates domain walls and metastable vacua in hot orientifold SU(N) gauge theories, calculating domain wall tensions, comparing with related theories, and analyzing vacuum stability and lifetimes.

Contribution

It provides a two-loop calculation of domain wall tension, confirms large-N equivalence non-perturbatively, and explores metastable vacua with lifetime estimates.

Findings

Domain wall tension matches in orientifold and adjoint theories at large-N.

Existence of N-2 metastable vacua with calculable lifetimes.

Large-N planar equivalence holds for domain wall tensions.

Abstract

We consider "Orientifold field theories", namely SU(N) gauge theories with Dirac fermions in the two-index representation at high temperature. When N is even these theories exhibit a spontaneously broken Z2 centre symmetry. We study aspects of the domain wall that interpolates between the two vacua of the theory. In particular we calculate its tension to two-loop order. We compare its tension to the corresponding domain wall in a SU(N) gauge theory with adjoint fermions and find an agreement at large-N, as expected from planar equivalence between the two theories. Moreover, we provide a non-perturbative proof for the coincidence of the tensions at large-N. We also discuss the vacuum structure of the theory when the fermion is given a large mass and argue that there exist N-2 metastable vacua. We calculate the lifetime of those vacua in the thin wall approximation.