Stochastic Dynamics and Bound States of Heavy Impurities in a Fermi Bath

TL;DR

This paper models the stochastic dynamics of heavy impurities in a Fermi gas, revealing bound states and impurity interactions influenced by quantum effects, with predictions applicable to current cold-gas experiments.

Contribution

It introduces a generalized Langevin framework for impurity dynamics in a Fermi bath, predicting bound states and impurity interactions under various conditions.

Findings

Existence of impurity bound states predicted

Impurity interactions depend on coupling and temperature

Analytical estimates of bound state lifetime provided

Abstract

We investigate the dynamics of heavy impurities embedded in an ultra-cold Fermi gas by using a Generalized Langevin equation. The latter -- derived by means of influence functional theory -- describes the stochastic classical dynamics of the impurities and the quantum nature of the fermionic bath manifests in the emergent interaction between the impurities and in the viscosity tensor. By focusing on the two-impurity case, we predict the existence of bound states, in different conditions of coupling and temperature, and whose life-time can be analytically estimated. Our predictions should be testable using cold-gases platforms within current technology.