Phase separation in a polarized Fermi gas with spin-orbit coupling

TL;DR

This paper investigates how spin-orbit coupling influences phase separation and the emergence of topologically non-trivial gapless superfluid states in a polarized Fermi gas near a Feshbach resonance, highlighting potential for experimental realization.

Contribution

It reveals the rich phase diagram with stable gapless topological superfluid phases induced by spin-orbit coupling and population imbalance in a polarized Fermi gas.

Findings

Phase separation involves topologically non-trivial gapless superfluid states.

Intermediate spin-orbit coupling stabilizes these novel phases.

External trapping can induce phase separation suitable for experiments.

Abstract

We study the phase separation of a spin polarized Fermi gas with spin-orbit coupling near a wide Feshbach resonance. As a result of the competition between spin-orbit coupling and population imbalance, the phase diagram for a uniform gas develops a rich structure of phase separation involving gapless superfluid states which are topologically non-trivial. We find that these novel gapless phases can be stabilized by intermediate spin-orbit coupling strengths. We then demonstrate the phase separation induced by an external trapping potential and discuss the optimal parameter region for the experimental observation of the gapless superfluid phases.