Thermal Ising transition in two-dimensional SU(3) Fermi lattice gases with population imbalance

TL;DR

This paper investigates a phase transition in two-dimensional SU(3) Fermi gases with population imbalance, revealing an Ising transition driven by thermal fluctuations and interactions, with implications for cold atom experiments.

Contribution

It introduces a novel Ising transition in a non-frustrated low-dimensional system with continuous symmetries, analyzed through mean-field and semi-classical Monte Carlo methods.

Findings

Identification of an Ising symmetry-breaking transition

Analysis of thermal fluctuation effects on the phase diagram

Proposal for experimental realization with cold atoms

Abstract

We focus on three-component SU(3) Fermi gases loaded into a square optical lattice, with population imbalance between one component and the others. At strong coupling the system is described by the SU(3) Heisenberg model with an external field that couples to the population imbalance. We discuss the ground state at the mean-field level and then analyze the thermal fluctuations with the semi-classical Monte Carlo method. The interplay of interactions, population imbalance and thermal fluctuations gives rise to a phase transition linked to the breaking of an emergent Ising symmetry, despite the absence of frustration. This represents a new scenario of discrete symmetry breaking in low-dimensional systems with continuous symmetries. Possible implementations with cold alkaline-earth(-like) atoms are discussed.