Non-equilibrium phases of Fermi gas inside a cavity with imbalanced pumping

TL;DR

This paper explores the non-equilibrium behavior of one-dimensional spinless fermions in a cavity with imbalanced pumping, revealing multiple superradiant phases, an unstable phase, and proposing a novel topological pumping method that preserves time-reversal symmetry.

Contribution

It introduces the study of fermionic systems in cavity QED with imbalanced pumping, highlighting unique phases and proposing a time-reversal invariant topological pumping mechanism.

Findings

Multiple superradiant steady phases identified

Existence of an unstable phase in the system

Proposal of a unidirectional topological pumping method

Abstract

In this work, we investigate the non-equilibrium dynamics of one-dimensional spinless fermions loaded in a cavity with imbalanced pumping lasers. Our study is motivated by previous work on a similar setup using bosons, and we explore the unique properties of fermionic systems in this context. By considering the imbalance in the pumping, we find that the system exhibits multiple superradiant steady phases and an unstable phase. Furthermore, by making use of the hysteresis structure of superradiant phases, we propose a unidirectional topological pumping. Unlike the usual topological pumping in which the driving protocol breaks time reversal symmetry, the driving protocol can be time reversal invariant in our proposal.