Vortex dipoles in expanding shell-shaped Bose-Einstein condensates

TL;DR

This paper studies how vortex-antivortex dipoles influence the dynamics of expanding shell-shaped Bose-Einstein condensates, revealing symmetry breaking and non-monotonic aspect ratio behavior.

Contribution

It demonstrates the impact of vortex dipoles on shell-shaped BEC dynamics and proposes methods for their preparation and detection in curved superfluid geometries.

Findings

Increasing vortex dipole separation breaks spherical symmetry.

Vortex physics and curvature cause non-monotonic aspect ratio behavior.

Features aid in preparing and detecting vortex dipoles in superfluids.

Abstract

Releasing shell-shaped Bose-Einstein condensates from their confinement produces a spherically symmetric density distribution characterized by concentric ripples surrounding a central peak. Here we investigate how a vortex-antivortex dipole affects this dynamics, finding that increasing dipole separation progressively breaks the spherical symmetry and, correspondingly, the interplay of vortex physics and curvature produces a non-monotonic behavior of the cloud aspect ratio. These features can be used for preparing and detecting vortex dipoles in shell-shaped superfluids, as well as for analyzing their signatures in other thin superfluids with more general curved geometries.