Quantum Monte Carlo simulation of thermodynamic properties of SU(2N) ultracold fermions in optical lattices

TL;DR

This study uses determinant quantum Monte Carlo to analyze thermodynamic properties of SU(2N) Hubbard models in 2D optical lattices, revealing how increasing fermion components affects charge and spin behaviors.

Contribution

It provides the first systematic quantum Monte Carlo analysis of thermodynamics in SU(2N) Hubbard models, highlighting the impact of fermion components on interaction and spin fluctuations.

Findings

Entropy-temperature relation shows Pomeranchuk effect features.

Crossover interaction strength increases with fermion components.

Enhanced quantum spin fluctuations with more fermion components.

Abstract

We have systematically studied the thermodynamic properties of a two-dimensional half-filled SU(2N) Hubbard model on a square lattice by using the determinant quantum Monte Carlo method. The entropy-temperature relation, the isoentropy curve, and the probability distribution of the onsite occupation number are calculated in both SU(4) and SU(6) cases, which exhibit prominent features of the Pomeranchuk effect. We analyze these thermodynamic behaviors based on charge and spin energy scales. In the charge channel, the interaction strength that marks the crossover from the weak to strong interaction regimes increases with the number of fermion components. In the spin channel, increasing the number of fermion components enhances quantum spin fluctuations, which is shown in the simulations of uniform spin susceptibilities and antiferromagnetic structure factors.