Finite-range effects in the unitary Fermi polaron
Renato Pessoa, S. A. Vitiello, Luis A. Peña Ardila
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.