Mixtures of fermionic atoms in an optical lattice

TL;DR

This paper investigates a mixture of light and heavy fermionic atoms in an optical lattice, revealing complex phase transitions driven by quantum tunneling and thermal fluctuations, including first- and second-order transitions.

Contribution

It introduces a model describing the interplay between light and heavy fermions in an optical lattice, highlighting phase transitions and effective interactions caused by quantum tunneling.

Findings

Heavy atom distribution follows an Ising-like pattern.

First-order transition from homogeneous to staggered order.

Second-order transition between ordered and disordered phases.

Abstract

A mixture of light and heavy spin-polarized fermionic atoms in an optical lattice is considered. Tunneling of the heavy atoms is neglected such that they are only subject to thermal fluctuations. This results in a complex interplay between light and heavy atoms caused by quantum tunneling of the light atoms. The distribution of the heavy atoms is studied. It can be described by an Ising-like distribution with a first-order transition from homogeneous to staggered order. The latter is caused by an effective nonlocal interaction due to quantum tunneling of the light atoms. A second-order transition is also possible between an ordered and a disordered phase of the heavy atoms.