Gyroscopic motion of superfluid trapped atomic condensates

TL;DR

This paper investigates the gyroscopic motion of vortices in trapped superfluid Bose gases using multiple modeling approaches, revealing quantum effects on precession frequencies and vortex dynamics consistent with experiments.

Contribution

It provides a comprehensive analysis combining classical, hydrodynamic, and quantum models to describe vortex precession and dynamics in superfluid condensates, highlighting quantum frequency shifts.

Findings

Quantum frequency shifts influence vortex precession.

Classical and hydrodynamic models effectively describe superfluid precession.

Vortex bending and twisting involve quantal excitations, notably Kelvin waves.

Abstract

The gyroscopic motion of a trapped Bose gas containing a vortex is studied. We model the system as a classical top, as a superposition of coherent hydrodynamic states, by solution of the Bogoliubov equations, and by integration of the time-dependent Gross-Pitaevskii equation. The frequency spectrum of Bogoliubov excitations, including quantum frequency shifts, is calculated and the quantal precession frequency is found to be consistent with experimental results, though a small discrepancy exists. The superfluid precession is found to be well described by the classical and hydrodynamic models. However the frequency shifts and helical oscillations associated with vortex bending and twisting require a quantal treatment. In gyroscopic precession, the vortex excitation modes $m=\pm 1$ are the dominant features giving a vortex kink or bend, while the $m=+2$ is found to be the dominant Kelvin wave associated with vortex twisting.