Precession of Vortices in Dilute Bose-Einstein Condensates at Finite Temperature

TL;DR

This paper shows that vortex precession frequencies in Bose-Einstein condensates at finite temperature are governed by a conservation law, not by excitation energies, and confirms this through theoretical calculations and simulations.

Contribution

It introduces a conservation law-based method to determine vortex precession frequencies at finite temperature, extending previous zero-temperature results.

Findings

Precession frequencies are governed by a conservation law.

Agreement with zero-temperature Bogoliubov approximation.

Precession frequency varies smoothly with temperature.

Abstract

We demonstrate that the precessional frequencies of vortices in Bose Einstein condensates (BECs) are determined by a conservation law, and not by the lowest lying excitation energy mode. We determine the precessional frequency for a single off-axis vortex and vortex lattices in BECs using the continuity equation, and solve this self-consistently with the time-independent Hartree-Fock-Bogoliubov (HFB) equations in the rotating frame. We find agreement with zero temperature calculations (Bogoliubov approximation), and a smooth variation in the precession frequency as the temperature is increased. Time-dependent solutions confirm the validity of these predictions.