English

Order from chaos: Observation of large-scale flow from turbulence in a two-dimensional superfluid

Quantum Gases 2019-09-04 v2 Fluid Dynamics

Abstract

Interacting systems driven far from equilibrium tend to evolve to steady states exhibiting large-scale structure and order. In two-dimensional turbulent flow the seemingly random swirling motion of a fluid can evolve towards persistent large-scale vortices. Lars Onsager proposed a model based on statistical mechanics of quantized vortices to explain such behavior. Here we report the first experimental confirmation of Onsager's model of turbulence. We drag a grid barrier through an oblate superfluid Bose--Einstein condensate to generate non-equilibrium distributions of vortices. We observe an inverse energy cascade driven by the evaporative heating of vortices, leading to steady-state configurations characterized by negative temperatures. Our results open a pathway for quantitative studies of emergent structures in interacting quantum systems driven far from equilibrium.

Keywords

Cite

@article{arxiv.1801.06952,
  title  = {Order from chaos: Observation of large-scale flow from turbulence in a two-dimensional superfluid},
  author = {Shaun P. Johnstone and Andrew J. Groszek and Philip T. Starkey and Christopher J. Billington and Tapio P. Simula and Kristian Helmerson},
  journal= {arXiv preprint arXiv:1801.06952},
  year   = {2019}
}

Comments

11 pages, 4 figures, 8 supplementary figures