Resonant enhancement of the FFLO-state in 3D by a one-dimensional optical potential

TL;DR

This paper models an imbalanced superfluid Fermi gas in three dimensions, demonstrating that a one-dimensional optical potential can significantly enhance the stability of the FFLO state and linking its properties to the optical wavevector.

Contribution

It introduces a path-integral framework for the FFLO state in 3D Fermi gases and shows how a 1D optical potential can resonantly stabilize this state.

Findings

Optical potential enlarges FFLO stability region

Direct relation between FFLO pair momentum and optical wavevector

Resonant enhancement of FFLO stability proposed

Abstract

We describe an imbalanced superfluid Fermi gas in three dimensions within the path-integral framework. To allow for the formation of the Fulde-Ferell-Larkin-Ovchinnikov-state (FFLO-state), a suitable form of the saddle-point is chosen, in which the pairs have a finite centre-of-mass momentum. To test the correctness of this path-integral description, the zero-temperature phase diagram for an imbalanced Fermi gas in three dimensions is calculated, and compared to recent theoretical results. Subsequently, we investigate two models that describe the effect of imposing a one-dimensional optical potential on the 3D imbalanced Fermi gas. We show that this 1D optical potential can greatly enlarge the stability region of the FFLO-state, relative to the case of the 3D Fermi gas without 1D periodic modulation. Furthermore it is show that there exists a direct connection between the centre-of-mass momentum of the FFLO-pairs and the wavevector of the optical potential. We propose that this concept can be used experimentally to resonantly enhance the stability region of the FFLO-state.