Probing the FFLO phase by double occupancy modulation spectroscopy

TL;DR

This paper proposes a spectroscopy method using double occupancy modulation to detect the FFLO phase in a 1D spin-imbalanced Fermi gas, linking spectral features to the FFLO wavevector.

Contribution

It introduces a novel spectroscopic approach to identify the FFLO phase via double occupancy measurements in a 1D optical lattice.

Findings

Double occupancy spectrum features relate to the FFLO wavevector.

Narrowing of the spectrum indicates the presence of the FFLO phase.

Bethe-ansatz equations connect spectral width to the FFLO wavevector.

Abstract

We propose here that for a spin-imbalanced two-component attractive Fermi gas loaded in a 1D optical lattice in presence of an harmonic confining potential, the observation of the change in the double occupancy after a lattice depth modulation can provide clear evidence of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase. Simulating the time evolution of the system, we can characterize the double occupancy spectrum for different initial conditions, relating its features to the FFLO wavevector $q$. In particular, the narrowing of the width of the spectrum can be related, through Bethe-ansatz equations in the strongly interacting limit, to the FFLO wavevector $q$.