Fermi polaron in a dissipative bath with spin-orbit coupling

TL;DR

This paper investigates how dissipation and spin-orbit coupling in a Fermi gas affect polaron properties, revealing non-Hermitian effects on dispersion, stability, and interactions, with potential for experimental realization.

Contribution

It introduces a non-Hermitian model for a dissipative spin-orbit coupled Fermi bath and analyzes its impact on polaron physics, extending understanding to non-Hermitian quantum systems.

Findings

Non-Hermiticity alters single-particle dispersion and polaron properties.

Stronger dissipation facilitates polaron molecule formation.

The study provides a feasible experimental scheme for realization.

Abstract

We study the polaron problem of an impurity immersed in a dissipative spin-orbit coupled Fermi gas via a non-self-consistent T-matrix method. We first propose an experimental scheme to realize a spin-orbit coupled Fermi bath with dissipation, and show that such a system can be described by a non-Hermitian Hamiltonian that contains an imaginary spin-flip term and an imaginary constant shift term. We find that the non-Hermiticity will change the single particle dispersion of the bath gas, and modify the properties of attractive and repulsive polarons such as energy, quasi-particle residue, effective mass, and decay rate. We also investigate the Thouless criteria corresponding to the instability of the polaron molecule transition, which suggests a molecule state is more facilitated with stronger bath dissipation. Finally, we consider the case with finite impurity density and calculate the interaction between polarons. Our result extends the study of polaron physics to non-Hermitian systems and may be realized in future experiment.