Dynamics of Few Co-rotating Vortices in Bose-Einstein Condensates

TL;DR

This paper investigates the complex dynamics of small co-rotating vortex clusters in Bose-Einstein condensates, revealing instabilities and bifurcations through experiments, simulations, and theory, including chaotic behaviors in multi-vortex systems.

Contribution

It provides a comprehensive analysis of vortex dynamics in BECs, highlighting the emergence of asymmetric configurations and instabilities at high angular momentum, supported by experimental and theoretical methods.

Findings

Symmetric vortex configurations become unstable at high angular momentum.

Asymmetric vortex states emerge and stabilize via bifurcations.

Chaotic trajectories are observed in multi-vortex systems.

Abstract

We study the dynamics of small vortex clusters with few (2--4) co-rotating vortices in Bose-Einstein condensates by means of experiments, numerical computations, and theoretical analysis. All of these approaches corroborate the counter-intuitive presence of a dynamical instability of symmetric vortex configurations. The instability arises as a pitchfork bifurcation at sufficiently large values of the angular momentum that induces the emergence and stabilization of asymmetric rotating vortex configurations. The latter are quantified in the theoretical model and observed in the experiments. The dynamics is explored both for the integrable two-vortex system, where a reduction of the phase space of the system provides valuable insight, as well as for the non-integrable three- (or more) vortex case, which additionally admits the possibility of chaotic trajectories.