Quantum phases of atomic Fermi gases with anisotropic spin-orbit coupling

TL;DR

This paper explores the phase diagrams of atomic Fermi gases with anisotropic spin-orbit coupling across the BCS-BEC crossover, demonstrating the robustness of topological phases and analyzing fluctuation effects near critical temperature.

Contribution

It provides a comprehensive analysis of phase diagrams under anisotropic SOC, combining mean-field and fluctuation theories, and derives effective pair mass and critical temperature in the BEC limit.

Findings

Topological phase structures are robust against anisotropy.

Gaussian fluctuations influence critical temperature near the transition.

Effective mass of Cooper pairs is derived in the molecular BEC limit.

Abstract

We consider a general anisotropic spin-orbit coupling (SOC) and analyze the phase diagrams of both balanced and imbalanced Fermi gases for the entire BCS--Bose-Einstein condensate (BEC) evolution. In the first part, we use the self-consistent mean-field theory at zero temperature, and show that the topological structure of the ground-state phase diagrams is quite robust against the effects of anisotropy. In the second part, we go beyond the mean-field description, and investigate the effects of Gaussian fluctuations near the critical temperature. This allows us to derive the time-dependent Ginzburg-Landau theory, from which we extract the effective mass of the Cooper pairs and their critical condensation temperature in the molecular BEC limit.