Stability of spin-orbit coupled Fermi gases with population imbalance

TL;DR

This paper investigates how Rashba spin-orbit coupling influences the phase diagram of population-imbalanced Fermi gases, revealing stabilization effects, phase transitions, and topological changes across the BCS-BEC crossover.

Contribution

It provides a comprehensive mean-field analysis of the interplay between SOC and population imbalance, highlighting new topological quantum phase transitions and stability regimes.

Findings

SOC stabilizes the superfluid phase against phase separation.

Topological quantum phase transitions occur with zero quasiparticle energies.

Momentum distribution signatures of phase transitions are identified.

Abstract

We use the self-consistent mean-field theory to analyze the effects of Rashba-type spin-orbit coupling (SOC) on the ground-state phase diagram of population-imbalanced Fermi gases throughout the BCS-BEC evolution. We find that the SOC and population imbalance are counteracting, and that this competition tends to stabilize the uniform superfluid phase against the phase separation. However, we also show that the SOC stabilizes (destabilizes) the uniform superfluid phase against the normal phase for low (high) population imbalances. In addition, we find topological quantum phase transitions associated with the appearance of momentum space regions with zero quasiparticle energies, and study their signatures in the momentum distribution.