Condensation of `composite bosons' in a rotating BEC

TL;DR

This paper investigates novel phases in rotating Bose-Einstein condensates, revealing that near-integer angular momentum states are best described as condensates of composite particles involving vortices, with parallels to fractional quantum Hall states.

Contribution

It introduces a new perspective on rotating BECs as condensates of composite entities, supported by exact calculations and comparisons with vortex-only descriptions.

Findings

Identification of novel phases near integer angular momentum

Evidence for composite boson condensation involving vortices

Parallel with fractional quantum Hall states, including the Pfaffian state

Abstract

We provide evidence for several novel phases in the dilute limit of rotating BECs. By exact calculation of wavefunctions and energies for small numbers of particles, we show that the states near integer angular momentum per particle are best considered condensates of composite entities, involving vortices and atoms. We are led to this result by explicit comparison with a description purely in terms of vortices. Several parallels with the fractional quantum Hall effect emerge, including the presence of the Pfaffian state.