Spin-Orbit Coupled Fermi Gases across a Feshbach Resonance

TL;DR

This paper investigates how synthetic spin-orbit coupling influences the ground state and superfluid transition temperature of a Fermi gas across a Feshbach resonance, revealing significant enhancements in pairing and transition temperature due to strong spin-orbit coupling.

Contribution

It provides a combined mean-field and exact two-body analysis of spin-orbit coupled Fermi gases, highlighting the impact of spin-orbit coupling on pairing and superfluidity across the resonance.

Findings

Strong spin-orbit coupling enhances pairing gap for certain interaction regimes.

Superfluid transition temperature increases significantly with strong spin-orbit coupling in some regimes.

Universal interaction energy and pair size at resonance are characterized.

Abstract

In this letter we study both ground state properties and the superfluid transition temperature of a spin-1/2 Fermi gas across a Feshbach resonance with a synthetic spin-orbit coupling, using mean-field theory and exact solution of two-body problem. We show that a strong spin-orbit coupling can significantly enhance the pairing gap for 1/(k_F a_s)<=0 due to increased density-of-state. Strong spin-orbit coupling also significantly enhances the superfluid transition temperature when 1/(k_F a_s)<=0, while suppresses it slightly when 1/(k_F a_s)>0. The universal interaction energy and pair size at resonance are also discussed.