Itinerant ferromagnetism in a two-dimensional atomic gas

TL;DR

This paper investigates the potential for itinerant ferromagnetism in a two-dimensional ultracold atomic gas, highlighting the role of quantum fluctuations and population imbalance in driving ferromagnetic behavior.

Contribution

It introduces a formalism showing quantum fluctuations induce first-order ferromagnetic transitions and adapts it to realistic trapped geometries.

Findings

Quantum fluctuations drive first-order ferromagnetic reconstruction.

Population imbalance influences ferromagnetic properties.

Key experimental signatures are identified for trapped geometries.

Abstract

Motivated by the first experimental evidence of ferromagnetic behavior in a three-dimensional ultracold atomic gas, we explore the possibility of itinerant ferromagnetism in a trapped two-dimensional atomic gas. Firstly, we develop a formalism that demonstrates how quantum fluctuations drive the ferromagnetic reconstruction first order, and consider the consequences of an imposed population imbalance. Secondly, we adapt this formalism to elucidate the key experimental signatures of ferromagnetism in a realistic trapped geometry.