Entanglement and exotic superfluidity in spin-imbalanced lattices

TL;DR

This paper explores entanglement properties in one-dimensional fermionic lattices within the FFLO superfluid regime, revealing non-monotonic entanglement behavior that signals exotic superfluid phases.

Contribution

It provides analytical and numerical analysis of entanglement in FFLO superfluids, highlighting a unique entanglement signature at the phase transition.

Findings

Entanglement shows non-monotonic behavior in superfluid regimes.

A breaking pairs avalanche occurs at the FFLO-normal phase transition.

Entanglement features can serve as signatures of exotic superfluidity.

Abstract

We investigate the properties of entanglement in one-dimensional fermionic lattices at the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superfluid regime. By analyzing occupation probabilities, which are concepts closely related to FFLO and entanglement, we obtain approximate analytical expressions for the spin-flip processes at the FFLO regime. We also apply density matrix renormalization group calculations to obtain the exact ground-state entanglement of the system in superfluid and non-superfluid regimes. Our results reveal a breaking pairs avalanche appearing precisely at the FFLO-normal phase transition. We find that entanglement is non-monotonic in superfluid regimes, feature that could be used as a signature of exotic superfluidity.