Generation and Dynamics of Quantized Vortices in a Unitary Fermi Superfluid

TL;DR

This paper develops a local extension of time-dependent density functional theory to model the complex dynamics of fermionic superfluids, including vortex behavior and phase transitions, revealing new phenomena like stable superfluidity at high stirring velocities.

Contribution

It introduces a novel theoretical framework that accurately describes vortex dynamics and phase transitions in fermionic superfluids beyond existing models.

Findings

Successful simulation of vortex generation and reconnection

Prediction of stable superfluidity at supercritical velocities

Observation of new collective modes in superfluid dynamics

Abstract

Superfluidity and superconductivity are remarkable manifestations of quantum coherence at a macroscopic scale. The dynamics of superfluids has dominated the study of these systems for decades now, but a comprehensive theoretical framework is still lacking. We introduce a local extension of the time-dependent density functional theory to describe the dynamics of fermionic superfluids. Within this approach one can correctly represent vortex quantization, generation, and dynamics, the transition from a superfluid to a normal phase and a number of other large amplitude collective modes which are beyond the scope of two-fluid hydrodynamics, Ginzburg-Landau and/or Gross-Pitaevskii approaches. We illustrate the power of this approach by studying the generation of quantized vortices, vortex rings, vortex reconnection, and transition from a superfluid to a normal state in real time for a unitary Fermi gas. We predict the emergence of a new qualitative phenomenon in superfluid dynamics of gases, the existence of stable superfluidity when the systems are stirred with velocities significantly exceeding the nominal Landau critical velocity in these systems.