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arXiv · 2105.11509

The sound-ring radiation of expanding vortex clusters

August Geelmuyden·Sebastian Erne·Sam Patrick·Carlo Barenghi·Silke Weinfurtner
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Abstract

We investigate wave-vortex interaction emerging from an expanding compact vortex cluster in a two-dimensional Bose-Einstein condensate. We adapt techniques developed for compact gravitational objects to derive the characteristic modes of the wave-vortex interaction perturbatively around an effective vortex flow field. We demonstrate the existence of orbits or sound-rings, in analogy to gravitational light-rings, and compute the characteristic spectrum for the out-of-equilibrium vortex cluster. The spectrum obtained from numerical simulations of a stochastic Gross-Pitaevskii equation exhibiting an expanding vortex cluster is in excellent agreement with analytical predictions. Our findings are relevant for 2d-quantum turbulence, the semi-classical limit around fluid flows, and rotating compact objects exhibiting discrete circulation.

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August Geelmuyden, Sebastian Erne, Sam Patrick, Carlo Barenghi, Silke Weinfurtner. 2021-05-24. The sound-ring radiation of expanding vortex clusters. https://doi.org/10.1103/physrevresearch.4.023099

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