Pomeranchuk cooling of the SU($2N$) ultra-cold fermions in optical lattices

TL;DR

This paper explores how increasing hyperfine-spin components in SU(2N) fermions enhances Pomeranchuk cooling in optical lattices, reaching temperatures suitable for observing quantum magnetic phenomena.

Contribution

It provides the first detailed quantum Monte Carlo study of thermodynamics in SU(2N) Fermi-Hubbard models, demonstrating the cooling effect at large N without the fermion sign problem.

Findings

Enhanced spin fluctuations facilitate Pomeranchuk cooling at SU(6).

Calculated entropy, charge fluctuations, and spin correlations support cooling effectiveness.

Temperatures comparable to superexchange energy are achievable for large N.

Abstract

We investigate the thermodynamic properties of a half-filled SU(2N) Fermi-Hubbard model in the two-dimensional square lattice using the determinantal quantum Monte Carlo simulation, which is free of the fermion "sign problem". The large number of hyperfine-spin components enhances spin fluctuations, which facilitates the Pomeranchuk cooling to temperatures comparable to the superexchange energy scale at the case of SU$(6)$. Various quantities including entropy, charge fluctuation, and spin correlations have been calculated.