Population imbalance in the extended Fermi-Hubbard model

TL;DR

This paper investigates how population imbalance affects a two-component fermionic system with nearest-neighbor interactions, revealing a new FFLO phase, hidden order, and oscillations in string correlations using matrix product states.

Contribution

It introduces a new FFLO phase in the extended Fermi-Hubbard model and links population imbalance to hidden order and oscillatory correlations.

Findings

Discovery of a new FFLO phase under population imbalance

Evidence of hidden order in the system

Oscillations in string correlations linked to imbalance

Abstract

We study the interplay between population imbalance in a two-component fermionic system and nearest-neighbor interaction using matrix product states method. Our analysis reveals the existence of a new type of Fulde-Ferrell-Larkin-Ovchinnikov phase in the presence of competing interactions. Furthermore, we find distinct evidence for the presence of hidden order in the system. We present an effective model to understand the emergent oscillations in the string correlations due to the imbalance, and show how they can become an efficient tool to investigate systems with imbalance.