Angular Fulde-Ferrell-Larkin-Ovchinnikov state in cold fermion gases in a toroidal trap

TL;DR

This paper explores the emergence of an angular FFLO superfluid state in population-imbalanced fermion gases confined in toroidal traps, highlighting its stability near the BCS-BEC crossover and potential experimental signatures.

Contribution

It demonstrates the stabilization of the angular FFLO state in toroidal traps and analyzes its properties beyond local-density approximation.

Findings

Angular FFLO state is stabilized in toroidal traps.

State is stable near the BCS-BEC crossover due to pseudogap formation.

Provides spatial density and imbalance profiles for experimental detection.

Abstract

We study the possibility of angular Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, in which the rotation symmetry is spontaneously broken, in population imbalanced fermion gases near the BCS-BEC crossover. We investigate the superfluid gases at low temperatures on the basis of the Bogoliubov-de Gennes equation, and examine the stability against thermal fluctuations using the T-matrix approach beyond the local-density approximation (LDA). We find that the angular FFLO state is stabilized in the gases confined in the toroidal trap but not in the harmonic trap. The angular FFLO state is stable near the BCS-BEC crossover owing to the formation of pseudogap. Spatial dependences of number density and local population imbalance are shown for an experimental test.