Stability of FFLO states in optical lattices with bilayer structure

TL;DR

This paper studies the stability of FFLO superfluid states in bilayer optical lattices, revealing how interlayer hopping influences the stability of radial and angular FFLO states and examining system size effects.

Contribution

It demonstrates that interlayer hopping stabilizes radial FFLO states but destabilizes angular FFLO states in bilayer optical lattices.

Findings

Interlayer hopping stabilizes radial FFLO states in imbalanced systems.

Angular FFLO states become unstable with interlayer hopping.

Large system sizes can support the realization of A-FFLO states.

Abstract

We investigate the stability of the superfluid state in a bilayer fermionic optical lattice system with a confining potential, using the Bogoliubov de-Gennes equations. It is clarified that in the imbalanced case, the introduction of the interlayer hopping stabilizes the radial Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, while makes the angular FFLO state unstable. We also discuss the system size dependence of the superfluid ground state. It is clarified that in a certain ring region the A-FFLO state is indeed realized in a large system.