Signatures of unconventional pairing in spin-imbalanced one-dimensional few-fermion systems

TL;DR

This paper investigates how unconventional fermionic pairing signatures, specifically in the Fulde-Ferrell-Larkin-Ovchinnikov state, can be detected in a small, one-dimensional system of imbalanced attractively interacting $^6$Li atoms using noise correlation analysis.

Contribution

It demonstrates that signatures of exotic pairing mechanisms are observable in small, non-uniform systems, extending understanding beyond many-body limits.

Findings

Signatures of FFLO state detected in few-fermion systems

Correlations indicative of unconventional pairing are observable

Universal nature of exotic pairing mechanisms confirmed

Abstract

A system of a few attractively interacting fermionic $^6$Li atoms in one-dimensional harmonic confinement is investigated. Non-trivial inter-particle correlations induced by interactions in a particle-imbalanced system are studied in the framework of the noise correlation. In this way, it is shown that evident signatures of strongly correlated fermionic pairs in the Fulde-Ferrell-Larkin-Ovchinnikov state are present in the system and they can be detected by measurements directly accessible within state-of-the-art techniques. The results convincingly show that the exotic pairing mechanism is a very universal phenomenon and can be captured in systems being essentially non-uniform and far from the many-body limit.