A Cold Atomic Fermi Gas with a Spatially Modulated Interaction

TL;DR

This paper investigates a cold atomic Fermi gas with spatially modulated interactions, revealing a novel ground state related to FFLO states, with unique excitation spectra and potential experimental realization.

Contribution

It introduces a new ground state in a Fermi gas with periodically modulated interactions, expanding understanding of exotic pairing mechanisms.

Findings

Discovery of a novel ground state with non-zero momentum pairs

Multiple-gap structures in single-particle excitations

Feasibility of experimental realization via spatially modulated Feshbach resonance

Abstract

We study an ultra-cold atomic Fermi Gas with the atom-atom interaction modulated periodically in space. A novel ground state with cooper pairs occupying non-zero center of mass momenta is found. Such a state is closely related to the state proposed by Fulde, Ferrell, Larkin, and Ovchinnikov(FFLO). The resultant single particle excitations with momenta along the direction of the modulation shows multiple-gap structures. Such a system can be realized in experiment with a spatially modulated Feshbach resonance. Experimental signatures of such a state are discussed.