  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.
