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

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 semiclassical 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 another scenario of discrete symmetry breaking in low-dimensional systems with continuous symmetries. Possible implementations with cold alkaline-earth(-like) atoms are discussed.

Automated summary

We studied three-component SU(3) Fermi gases in a square optical lattice with population imbalance between one component and the others. At strong coupling, the system can be described by the SU(3) Heisenberg model with an external field coupling to the population imbalance. We discussed the ground state at the mean-field level and analyzed the thermal fluctuations using the semiclassical Monte Carlo method. The interplay between interactions, population imbalance, and thermal fluctuations leads to a phase transition related to the breaking of an emergent Ising symmetry, even in the absence of frustration. Possible implementations using cold alkaline-earth(-like) atoms are also discussed.