Finite-range effects in the unitary Fermi polaron

TL;DR

This study uses Quantum Monte Carlo methods to analyze how finite-range interactions affect the properties of Fermi polarons at unitarity, providing insights into effective mass, binding energy, and interaction effects.

Contribution

It introduces a detailed comparison between zero-range and finite-range potentials in Fermi polaron models, highlighting the impact of potential range on polaron properties.

Findings

Finite-range effects significantly influence polaron effective mass.

The polaron binding energy varies with potential range.

The contact parameter is estimated from pair distribution functions.

Abstract

Quantum Monte Carlo techniques are employed to study the properties of polarons in an ultracold Fermi gas, at $T= 0,$ and in the unitary regime using both a zero-range model and a square-well potential. For a fixed density, the potential range is varied and results are extrapolated and compared against a zero-range model. A discussion regarding the choice of an interacting potential with a finite range is presented. We compute the polaron effective mass, the polaron binding energy, and the effective coupling between them. The latter is obtained using the Landau-Pomeranchuk's weakly interacting quasiparticle model. The contact parameter is estimated by fitting the pair distribution function of atoms in different spin states.