Asymptotics in the bi-Yang-Baxter Sigma Model

TL;DR

This paper applies Volin's large-charge method to the bi-Yang-Baxter deformed SU(2) principal chiral model, deriving an explicit asymptotic expansion for the free energy density and analyzing non-perturbative effects.

Contribution

It provides the first explicit asymptotic expression for free energy in the bi-Yang-Baxter model using large-charge techniques.

Findings

Derived an explicit asymptotic expansion for free energy density.

Identified leading non-perturbative effects through analytic and resurgence methods.

Extended large-charge analysis to a deformed integrable model.

Abstract

Working in a sector of large charge is a powerful tool to analytically access models that are either strongly coupled or otherwise difficult to solve explicitly. In the context of integrable systems, Volin's method is exactly such a large-charge approach. In this note, we apply this method to the bi-Yang-Baxter deformed $SU(2)$ principal chiral model. Our main result is an explicit expression for the free energy density as an asymptotic expansion. We moreover determine the leading non-perturbative effects both via analytic methods and a resurgence analysis.