Polaronic effects of an impurity in a Fermi superfluid away from the BEC limit

TL;DR

This paper investigates how an impurity interacts with excitations in a Fermi superfluid across the BEC-BCS crossover, revealing how polaron properties evolve with interaction strength using an effective field theory approach.

Contribution

It introduces a novel analysis of polaronic effects in a Fermi superfluid away from the BEC limit by applying an effective field theory across the crossover.

Findings

Polaronic coupling constant $oldsymbol{ extalpha}$ varies across the crossover.

Effective mass of the polaron changes with interaction strength.

Dispersion relations for Bogoliubov excitations are interaction-dependent.

Abstract

In this article we study the interaction between an impurity and the gas of Bogoliubov excitations of a Fermi superfluid by mapping it on the polaron problem for an impurity in a BEC. The description of the Fermi superfluid across the BEC-BCS crossover regime is based on a recently developed effective field theory presented in [Eur. Phys. J. B 88, 122 (2015)] and provides us with the interaction-dependent dispersion relations for the Bogoliubov excitations. The behavior of the polaronic coupling constant $\alpha$ and of the effective mass of the polaron is examined in a broad window of the BEC-BCS crossover.