Metastability of persistent currents in trapped gases of atoms

TL;DR

This paper investigates the conditions under which trapped Bose-Einstein condensates can sustain metastable, persistent currents, emphasizing the roles of trapping potential shape, interatomic interactions, and vortex stability.

Contribution

It identifies the necessary conditions for metastability of persistent currents in trapped gases, including potential shape and interaction strength, and analyzes vortex stability and hysteresis effects.

Findings

Non-monotonically increasing trapping potentials are required for stability.

Strong, repulsive interatomic interactions are necessary.

Off-center vortex states are unstable, and hysteresis occurs in driven gases.

Abstract

We examine the conditions that give rise to metastable, persistent currents in a trapped Bose-Einstein condensate. A necessary condition for the stability of persistent currents is that the trapping potential is not a monotonically increasing function of the distance from the trap center. Persistent currents also require that the interatomic interactions are sufficiently strong and repulsive. Finally, any off-center vortex state is shown to be unstable, while a driven gas shows hysteresis.