Non-Hermitian BCS-BEC crossover of Dirac fermions

TL;DR

This paper explores how dissipation affects chiral symmetry breaking and the BCS-BEC crossover in Dirac fermions, revealing that dissipation can enhance mass generation but also restore symmetry beyond a threshold.

Contribution

It introduces a complexified coupling in a Dirac fermion model to study dissipation effects on chiral symmetry and the BCS-BEC crossover, providing a phase diagram analysis.

Findings

Dissipation increases the dynamical mass of Dirac fermions.

Chiral symmetry is restored when dissipation exceeds a critical threshold.

A relativistic BCS-BEC crossover is observed in the model.

Abstract

We investigate chiral symmetry breaking in a model of Dirac fermions with a complexified coupling constant whose imaginary part represents dissipation. We introduce a chiral chemical potential and observe that for real coupling a relativistic BCS-BEC crossover is realized. We solve the model in the mean-field approximation and construct the phase diagram as a function of the complex coupling. It is found that the dynamical mass increases under dissipation, although the chiral symmetry gets restored if dissipation exceeds a threshold.