Pair correlations of a spin-imbalanced Fermi gas on two-leg ladders

TL;DR

This paper investigates the pair correlations in a spin-imbalanced two-leg ladder with attractive interactions, revealing FFLO-like phases and phase separation behaviors through DMRG analysis.

Contribution

It provides the first detailed DMRG study of FFLO-like physics in a two-leg ladder with spin imbalance and attractive interactions.

Findings

Identification of FFLO-like regions in the phase diagram.

Observation of multiple pairing wave-vectors indicating FFLO correlations.

Discussion of phase separation scenarios in a harmonic trap.

Abstract

We study the pair correlations of a spin-imbalanced two-leg ladder with attractive interactions, using the density matrix renormalization group method (DMRG). We identify regions in the phase diagram spanned by the chemical potential and the magnetic field that can harbor Fulde-Ferrell-Larkin-Ovchinnikov (FFLO)-like physics. Results for the pair structure factor, exhibiting multiple pairing wave-vectors, substantiate the presence of FFLO-like correlations. We further discuss phase separation scenarios induced by a harmonic trap, which differ from the case of isolated chains.