Quantum Monte Carlo study of the role of p-wave interactions in ultracold repulsive Fermi gases

TL;DR

This study uses quantum Monte Carlo simulations to analyze how p-wave interactions influence the ground-state properties of ultracold Fermi gases, providing insights into their equation of state and effective mass with comparisons to perturbative theories.

Contribution

It offers a detailed quantum Monte Carlo analysis of p-wave interactions in ultracold Fermi gases, including ground-state energies and effective mass, extending understanding beyond mean-field approximations.

Findings

Good agreement with second-order perturbative results across interaction strengths.

Linear dependence of effective mass on p-wave scattering volume confirmed.

Ground-state energies match fourth-order expansions including p-wave effects.

Abstract

Single-component ultracold atomic Fermi gases are usually described using noninteracting many-fermion models. However, recent experiments reached a regime where $p$-wave interactions among identical fermionic atoms are important. In this paper, we employ variational and fixed-node diffusion Monte Carlo simulations to investigate the ground-state properties of single-component Fermi gases with short-range repulsive interactions. We determine the zero-temperature equation of state, and elucidate the roles played by the $p$-wave scattering volume and the $p$-wave effective range. A comparison against recently derived second-order perturbative results shows good agreement in a broad range of interaction strength. We also compute the quasiparticle effective mass, and we confirm the perturbative prediction of a linear contribution in the $p$-wave scattering volume, while we find significant deviations from the beyond-mean-field perturbative result, already for moderate interaction strengths. Finally, we determine ground-state energies for two-component unpolarized Fermi gases with both interspecies and intraspecies hard-sphere interactions, finding remarkable agreement with a recently derived fourth-order expansion that includes $p$-wave contributions.