Quantum Monte Carlo calculation of the zero-temperature phase diagram of the two-component fermionic hard-core gas in two dimensions

TL;DR

This study uses quantum Monte Carlo simulations to explore the zero-temperature phase diagram of two-component fermionic gases with hard-core interactions in two dimensions, finding no stable ferromagnetic fluid phase.

Contribution

It provides the first comprehensive quantum Monte Carlo analysis of the phase diagram for 2D fermionic hard-core gases, including effects of long-range interactions.

Findings

No stable ferromagnetic fluid phase detected.

Long-range r^(-3) interactions do not stabilize ferromagnetism.

Results include pair-correlation, structure factor, and momentum density data.

Abstract

Motivated by potential realizations in cold-atom or cold-molecule systems, we have performed quantum Monte Carlo simulations of two-component gases of fermions in two dimensions with hard-core interactions. We have determined the gross features of the zero-temperature phase diagram, by investigating the relative stabilities of paramagnetic and ferromagnetic fluids and crystals. We have also examined the effect of including a pairwise, long-range r^(-3) potential between the particles. Our most important conclusion is that there is no region of stability for a ferromagnetic fluid phase, even if the long-range interaction is present. We also present results for the pair-correlation function, static structure factor, and momentum density of two-dimensional hard-core fluids.