Evolution of large-scale flow from turbulence in a two-dimensional superfluid

Shaun P. Johnstone, Andrew J. Groszek, Philip T. Starkey, Christopher J. Billington, Tapio P. Simula, Kristian Helmerson

Research output: Contribution to journalArticleResearchpeer-review

102 Citations (Scopus)


Nonequilibrium interacting systems can evolve to exhibit large-scale structure and order. In two-dimensional turbulent flow, the seemingly random swirling motion of a fluid can evolve toward persistent large-scale vortices. To explain such behavior, Lars Onsager proposed a statistical hydrodynamic model based on quantized vortices. Here, we report on the experimental confirmation of Onsager’s model. We dragged a grid barrier through an oblate superfluid Bose–Einstein condensate to generate nonequilibrium distributions of vortices. We observed signatures of an inverse energy cascade driven by the evaporative heating of vortices, leading to steady-state configurations characterized by negative absolute temperatures. Our results open a pathway for quantitative studies of emergent structures in interacting quantum systems driven far from equilibrium.
Original languageEnglish
Pages (from-to)1267-1271
Number of pages5
Issue number6447
Publication statusPublished - 28 Jun 2019

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