Synthetic dissipation and cascade fluxes in a turbulent quantum gas

Nir Navon; Christoph Eigen; Jinyi Zhang; Raphael Lopes; Alexander L. Gaunt; Kazuya Fujimoto; Makoto Tsubota; Robert P. Smith; Zoran Hadzibabic

doi:10.1126/science.aau6103

paper

Synthetic dissipation and cascade fluxes in a turbulent quantum gas

arXiv:1807.07564 · doi:10.1126/science.aau6103

Abstract

Scale-invariant fluxes are the defining property of turbulent cascades, but their direct measurement is a notorious problem. Here we perform such a measurement for a direct energy cascade in a turbulent quantum gas. Using a time-periodic force, we inject energy at a large lengthscale and generate a cascade in a uniformly-trapped Bose gas. The adjustable trap depth provides a high-momentum cutoff $k_{D}$ , which realises a synthetic dissipation scale. This gives us direct access to the particle flux across a momentum shell of radius $k_{D}$ , and the tunability of $k_{D}$ allows for a clear demonstration of the zeroth law of turbulence: we observe that for fixed forcing the particle flux vanishes as $k_{D}^{- 2}$ in the dissipationless limit $k_{D} \to \infty$ , while the energy flux is independent of $k_{D}$ . Moreover, our time-resolved measurements give unique access to the pre-steady-state dynamics, when the cascade front propagates in momentum space.

arXiv commentMain text: 4 pages, 4 figures. Supplementary Material: 2 pages, 3 figures

Synthetic dissipation and cascade fluxes in a turbulent quantum gas

Abstract

References in corpus (25)

Cited by in corpus (53)