From Low-Density Neutron Matter to the Unitary Limit

TL;DR

This paper uses Monte Carlo simulations of low-density neutron matter to extrapolate key properties at the unitary limit, revealing the physics's proximity and aligning well with existing literature.

Contribution

It introduces a smooth extrapolation method for Monte Carlo results to determine properties at the unitary limit in fermion systems.

Findings

Ground-state energy estimates at the unitary limit

Pairing gap values near zero temperature

Critical temperature for superfluid transition

Abstract

Various quantities of an attractively interacting fermion system at the unitary limit are determined by extrapolating Monte Carlo results of low-density neutron matter. Smooth extrapolation in terms of $1/(k_F a_0)$ ($k_F$ is the Fermi momentum, and $a_0$ is the ${}^1S_0$ scattering length) is found with the quantities examined: the ground-state energy, the pairing gap at $T \approx 0$, and the critical temperature of the normal-to-superfluid phase transition. We emphasize proximity of the physics of low-density neutron matter to that at the unitary limit. The extrapolated quantities are in a reasonable agreement with those in the literature.