Vortex Mass in Superfluid Fermi Gases along the BEC-BCS Crossover

TL;DR

This paper calculates the vortex mass in superfluid Fermi gases along the BEC-BCS crossover, revealing a strong size and interaction dependence, and suggests it could be experimentally observable due to its large magnitude.

Contribution

It introduces a logarithmic size dependence of vortex mass in superfluid Fermi gases, contrasting with previous local parameter assumptions, and analyzes its variation across the BEC-BCS crossover.

Findings

Vortex mass depends logarithmically on system size.

Vortex mass increases rapidly towards the BCS regime.

Predicted vortex mass is larger than previous models suggest.

Abstract

Vortex mass is a key concept in the study of superfluid dynamics, referring to the inertia of vortices in a superfluid, which affects their motion and behavior. Despite being an important quantity, the vortex mass has never been observed experimentally, and remains an unresolved issue in this field. As of now, a large body of research assumes that the vortex mass is a local parameter. In contrast, we present a calculation that suggests a logarithmic dependence on the system size, agreeing with some earlier predictions in the context of Bose gases. We analyze the problem using an effective field theory that describes ultracold atomic Fermi gases over the BEC-BCS crossover at both zero and nonzero temperatures. Our study reveals a strong dependence of the vortex mass on the scattering length; in particular, the vortex mass grows rapidly when moving towards the BCS side. Furthermore, we find that the system-size dependence of the vortex mass results in values an order of magnitude larger than those predicted by other models for realistic system sizes. This implies that the vortex mass could be observable in a wider parameter range than was previously expected. This is particularly relevant considering recent advances in experimental techniques that place the observation of vortex mass in superfluid Fermi gases within reach.