Nonequilibrium effects of anisotropic compression applied to vortex lattices in Bose-Einstein condensates

TL;DR

This paper investigates how anisotropic compression affects vortex lattices in Bose-Einstein condensates, revealing complex nonequilibrium dynamics and structural transformations induced by shape oscillations.

Contribution

It demonstrates the impact of large-amplitude quadrupolar oscillations on vortex lattice dynamics, including structural changes and vortex merging, in a dilute Bose-Einstein condensate.

Findings

Quadrupolar oscillations induce lattice plane shifts.

Large oscillations cause lattice structure changes.

Vortex merging and dissolution observed under excitation.

Abstract

We have studied the dynamics of large vortex lattices in a dilute-gas Bose-Einstein condensate. While undisturbed lattices have a regular hexagonal structure, large-amplitude quadrupolar shape oscillations of the condensate are shown to induce a wealth of nonequilibrium lattice dynamics. When exciting an m = -2 mode, we observe shifting of lattice planes, changes of lattice structure, and sheet-like structures in which individual vortices appear to have merged. Excitation of an m = +2 mode dissolves the regular lattice, leading to randomly arranged but still strictly parallel vortex lines.