Dynamics of spin-polarized impurity in ultracold Fermi gas

TL;DR

This paper investigates the behavior of spin-polarized impurities, called ferrons, in ultracold Fermi gases, revealing a critical velocity, effective mass scaling, and stability conditions near vortices.

Contribution

It introduces the concept of a critical velocity for ferrons, calculates their effective mass in two dimensions, and analyzes their stability near vortices, providing new insights into impurity dynamics.

Findings

Ferrons exhibit a critical velocity related to spin imbalance.

Effective mass of ferrons scales with their surface area.

Ferrons become unstable near vortex cores.

Abstract

We show that the motion of spin-polarized impurity (ferron) in ultracold atomic gas is characterized by a certain critical velocity which can be traced back to the amount of spin imbalance inside the impurity. We have calculated the effective mass of ferron in two dimensions. We show that the effective mass scales with the surface of the ferron. We discuss the impact of these findings; in particular, we demonstrate that ferrons become unstable in the vicinity of a vortex.