Spectral signatures of the Fulde-Ferrell-Larkin-Ovchinnikov order parameter in one-dimensional optical lattices

TL;DR

This paper demonstrates that the unique spectral features of the FFLO state in a 1D optical lattice can be directly observed through RF-spectra and photoemission measurements, revealing the oscillating order parameter.

Contribution

It provides a theoretical analysis showing how FFLO order signatures manifest in spectral measurements of a 1D atomic Fermi gas.

Findings

Andreev states are clearly resolvable in spectra

Spectral features directly indicate the oscillating order parameter

The study offers experimental signatures for FFLO detection

Abstract

We address an imbalanced two-component atomic Fermi gas restricted by a one-dimensional (1D) optical lattice and an external harmonic potential, within the mean-field Bogoliubov-de Gennes (BdG) formalism. We show that characteristic features of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state are visible in the RF-spectra and in the momentum resolved photoemission spectra of the gas. Specially, Andreev states or mid-gap states can be clearly resolved, which gives a direct experimentally observable signature of the oscillating order parameter.