Spin Localization of a Fermi Polaron in a Quasirandom Optical Lattice

TL;DR

This paper investigates how the spin in a strongly interacting Fermi gas localizes in a quasirandom optical lattice, revealing a transition between delocalized and localized states influenced by system filling and interaction strength.

Contribution

It introduces a novel analysis of spin localization in a Fermi polaron within a quasirandom lattice, connecting many-body localization with few-body system tools.

Findings

Identifies a delocalized-localized transition in spin states.

Transition nature varies with system filling.

Low fillings show different localization behavior due to diluteness.

Abstract

Recently, the topics of many-body localization (MBL) and one-dimensional strongly interacting few-body systems have received a lot of interest. These two topics have been largely developed separately. However, the generality of the latter as far as external potentials are concerned -- including random and quasirandom potentials -- and their shared spatial dimensionality, makes it an interesting way of dealing with MBL in the strongly interacting regime. Utilising tools developed for few-body systems we look to gain insight into the localization properties of the spin in a Fermi gas with strong interactions. We observe a delocalized--localized transition over a range of fillings of a quasirandom lattice. We find this transition to be of a different nature for low and high fillings, due to the diluteness of the system for low fillings.