Dissipative dynamics of an impurity with spin-orbit coupling

TL;DR

This paper models the dissipative dynamics of an impurity with spin-orbit coupling in cold Bose gases, deriving a master equation and analyzing how SOC influences impurity motion and spin polarization during quench dynamics.

Contribution

It introduces a Caldeira-Leggett-type model for impurity dynamics with SOC and demonstrates how SOC effects can be incorporated and studied in cold atom systems.

Findings

Impurity motion is primarily driven by dissipation at accessible temperatures.

Spin-orbit coupling effects can be gauged out in 1D systems, with information encoded in initial conditions.

Steady spin polarization domains can form during quench dynamics.

Abstract

Brownian motion of a mobile impurity in a bath is affected by spin-orbit coupling (SOC). Here, we discuss a Caldeira-Leggett-type model that can be used to propose and interpret quantum simulators of this problem in cold Bose gases. First, we derive a master equation that describes the model and explore it in a one-dimensional (1D) setting. To validate the standard assumptions needed for our derivation, we analyze available experimental data without SOC; as a byproduct, this analysis suggests that the quench dynamics of the impurity is beyond the 1D Bose-polaron approach at temperatures currently accessible in a cold-atom laboratory -- motion of the impurity is mainly driven by dissipation. For systems with SOC, we demonstrate that 1D spin-orbit coupling can be 'gauged out' even in the presence of dissipation -- the information about SOC is incorporated in the initial conditions. Observables sensitive to this information (such as spin densities) can be used to study formation of steady spin polarization domains during quench dynamics.