Rapidly rotating Bose-Einstein condensates in an anharmonic confinement

TL;DR

This paper studies the behavior of rapidly rotating Bose-Einstein condensates in anharmonic traps, revealing unique phase transitions, vortex structures, and critical frequencies distinct from harmonic confinement.

Contribution

It introduces an analysis of vortex lattice structures and phase transitions in anharmonic traps, highlighting differences from harmonic trap behavior.

Findings

Vortex lattice develops a central hole as rotation speed increases

Vortex becomes invisible at a certain critical rotation frequency

Phase diagram differs significantly from harmonic trap cases

Abstract

We examine a rapidly rotating Bose-Einstein condensate in an anharmonic confinement and find that many properties such as the critical rotating frequency and phase diagram are quite different from those in a harmonic trap. We investigate the phase transitions by means of average-vortex-approximation. We find that the vortex lattice consists of a vortex array with a hole in the center of the cloud as the rotating frequency $\Omega$ increases and the vortex becomes invisible when $\Omega$ reaches some value.