Phase diagram of rotating Bose-Einstein condensates trapped in power-law and hard-wall potentials

TL;DR

This paper maps the phase diagram of rotating Bose-Einstein condensates in power-law and hard-wall traps, revealing how confinement type influences vortex state transitions and density profiles.

Contribution

It provides a comparative analysis of phase transitions in BECs under different trapping potentials, highlighting qualitative differences in vortex behavior.

Findings

Weak interactions cause discontinuous transitions between vortex states.

Stronger interactions lead to continuous mixed vortex state transitions.

Hard-wall traps always involve states with nonzero density at the center.

Abstract

We investigate the rotational phase diagram of a quasi-two-dimensional, weakly-interacting Bose-Einstein condensate confined in power-law and in hard-wall trapping potentials. For weak interactions, the system undergoes discontinuous transitions between multiply-quantized vortex states as the rotation frequency of the trap increases. In contrast, stronger interactions induce continuous phase transitions toward mixed states involving both singly and multiply-quantized vortex states. A central result is the qualitative (and experimentally observable) difference between power-law and hard-wall confinement: In hard-wall traps, the leading instability always involves states with nonzero density at the trap center, whereas in power-law traps the density vanishes as the rotation frequency increases. The two different types of confinement give rise to scaling properties in the derived phase diagrams.