Vortex reconnections and rebounds in trapped atomic Bose--Einstein condensates

TL;DR

This paper investigates the dynamics of vortex reconnections in trapped atomic Bose-Einstein condensates, revealing phenomena like rebounds and ejections due to confinement effects, through experimental and numerical methods.

Contribution

It provides the first combined experimental and numerical analysis of vortex interactions in confined BECs, highlighting new behaviors caused by trapping.

Findings

Observation of vortex reconnections in trapped BECs

Identification of rebounds and ejections due to confinement

Confirmation of reconnection phenomena through simulations

Abstract

Reconnections and interactions of filamentary coherent structures play a fundamental role in the dynamics of fluids, plasmas and nematic liquid crystals. In fluids, vortex reconnections redistribute energy and helicity among the length scales and induce fine-scale turbulent mixing. Unlike ordinary fluids where vorticity is a continuous field, in quantum fluids vorticity is concentrated into discrete (quantized) vortex lines turning vortex reconnections into isolated events, making it conceptually easier to study. Here we report experimental and numerical observations of three-dimensional quantum vortex interactions in a cigar-shaped atomic Bose-Einstein Condensate (BEC). In addition to standard reconnections, already numerically and experimentally observed in homogeneous systems away from boundaries, we show that double reconnections, rebounds and ejections can also occur as a consequence of the non-homogeneous, confined nature of the system.