Dissipative dynamics of an impurity with spin-orbit coupling

Spin-orbit coupling (SOC) plays a central role in topological phases of matter. In reality, all of these topological materials are coupled to some dissipative environment, which affects the robustness of the phase. Surprisingly, SOC and dissipation are rarely considered together, which hinders our understanding of the interplay between the two phenomena. Here, we fill this gap by considering dissipative dynamics of a spin-orbit coupled particle in one dimension.

In addition, we suggest that the interplay between SOC and dissipation can be studied with cold-atom quantum simulators. A spin-orbit-coupled impurity in a Bose gas naturally reveals this interplay. A prerequisite for engineering such a quantum simulator is a theoretical tool that can be used to understand parameter regimes and relevant observables, and such a tool is presented and validated in our work.

First, we derive a master equation based upon an extended Caldeira-Leggett model. Second, we validate the applicability of this equation, making use of available experimental data (without SOC) for an impurity in a Bose gas, whose explanation posed a long-standing problem for theoreticians. Our method explains all features of the data, puts limits on formation of the Bose polaron, and suggests new experiments to study renormalization of the parameters of the impurity. Third, we show that a near-term experiment (with SOC) will be able to detect formation of domains of steady spin polarization by analyzing population of involved hyperfine levels.