Dissipation and Vortex Creation in Bose-Einstein Condensed Gases

TL;DR

This paper investigates how energy is transferred in a Bose-Einstein condensate when an oscillating object moves through it, revealing two regimes: phonon excitation below a critical velocity and vortex formation above it, aligning with experimental observations.

Contribution

The study provides a detailed analysis of dissipation mechanisms in Bose-Einstein condensates, highlighting the transition from phonon excitation to vortex creation as the velocity increases.

Findings

Energy transfer occurs via phonons below critical velocity.

Vortex formation dominates above critical velocity.

Enhanced heating correlates with vortex creation.

Abstract

We solve the Gross-Pitaevskii equation to study energy transfer from an oscillating `object' to a trapped Bose-Einstein condensate. Two regimes are found: for object velocities below a critical value, energy is transferred by excitation of phonons at the motion extrema; while above the critical velocity, energy transfer is via vortex formation. The second regime corresponds to significantly enhanced heating, in agreement with a recent experiment.