Emergence of isotropy and dynamic scaling in 2D wave turbulence in a homogeneous Bose gas

TL;DR

This study demonstrates the development of wave turbulence in a homogeneous 2D Bose gas, highlighting isotropy emergence and scaling laws, thus providing experimental insights into turbulence formation in quantum fluids.

Contribution

First experimental observation of turbulence cascade, isotropy emergence, and scaling laws in a homogeneous 2D Bose gas, confirming theoretical predictions.

Findings

Emergence of statistical momentum-space isotropy

Spatiotemporal scaling of momentum distribution

Build-up of turbulence from small to large momenta

Abstract

We realise a turbulent cascade of wave excitations in a homogeneous 2D Bose gas, and probe on all relevant time and length scales how it builds up from small to large momenta, until the system reaches a steady state with matching energy injection and dissipation. This all-scales view directly reveals the two theoretically expected cornerstones of turbulence formation -- the emergence of statistical momentum-space isotropy under anisotropic forcing, and the spatiotemporal scaling of the momentum distribution at times before any energy is dissipated.