Stationary states of Bose-Einstein condensed atoms rotating in an asymmetric ring potential

TL;DR

This paper studies the stationary states of a Bose-Einstein condensate in an asymmetric ring trap, revealing transitions from vortex states to solid-body rotation and identifying states with persistent currents despite being static.

Contribution

It introduces analysis of stationary states in asymmetric ring potentials, highlighting the existence of static states with nonzero circulation and the transition from vortex to solid-body motion.

Findings

Transition from vortex to solid-body rotation with increasing potential strength

Existence of static states with nonzero current (persistent currents)

Characterization of symmetry-breaking effects on condensate states

Abstract

We consider a Bose-Einstein condensate, which is confined in a very tight toroidal/annular trap, in the presence of a potential, which breaks the axial symmetry of the Hamiltonian. We investigate the stationary states of the condensate, when its density distribution co-rotates with the symmetry-breaking potential. As the strength of the potential increases, we have a gradual transition from vortex excitation to solid-body-like motion. Of particular importance are states where the system is static and yet it has a nonzero current/circulation, which is a realization of persistent currents/reflectionless potentials.