Entropy Signatures of Collective Modes and Vortex Dynamics in Rotating Two--Dimensional Bose--Einstein Condensates

TL;DR

This study explores the nonequilibrium dynamics of rotating 2D Bose gases, revealing how different excitations and vortices influence chaos and correlations, using information-theoretic measures for characterization.

Contribution

It introduces the use of information-theoretic measures to quantify many-body correlations and complexity in vortex dynamics of rotating Bose gases, highlighting sensitivity to excitation protocols.

Findings

Interaction quenches induce regular breathing in vortex-free states.

Giant vortices exhibit symmetry-breaking surface excitations under quenches.

Chaotic splitting correlates with growth in information-theoretic indicators.

Abstract

We investigate the nonequilibrium dynamics of a two-dimensional rotating Bose gas confined in a symmetric anharmonic trap, employing the multiconfigurational time-dependent Hartree method for bosons (MCTDHB). We study states ranging from vortex-free configurations to multicharged (giant) vortices, prepared by tuning the rotation frequency, and analyze their response to sudden interaction and trap quenches. In vortex-free states, interaction quenches induce regular breathing--like dynamics, whereas in the presence of giant vortices they lead to symmetry-breaking surface excitations. In contrast, trap deformations that excite quadrupole-like modes produce stable oscillations in vortex-free condensates but trigger rapid, irregular, and effectively chaotic splitting dynamics in multicharged vortices. To characterize these processes beyond conventional density and phase observables, we employ information-theoretic measures, including marginal and joint entropies, mutual information, and Kullback-Leibler (KL) divergence, supplemented by an angular-resolved KL measure that captures symmetry breaking and azimuthal localization. We find that chaotic splitting is accompanied by a pronounced growth of information-theoretic indicators, signaling the buildup of many-body correlations and increasing complexity in the system dynamics. Our results demonstrate the extreme sensitivity of giant vortices to excitation protocols and establish information-theoretic measures as a powerful framework to quantify correlations and complexity in rotating quantum gases.