Kolmogorov turbulence in atomic Bose-Einstein condensates

TL;DR

This study demonstrates the measurement of turbulence in atomic Bose-Einstein condensates using a novel impurity injection technique, revealing Kolmogorov scaling and intermittency effects consistent with classical turbulence theories.

Contribution

Introduces a minimally destructive impurity injection method to quantify turbulence in BECs, enabling direct comparison with classical fluid turbulence theories.

Findings

Velocity structure functions follow Kolmogorov scaling.

Velocity increments exhibit non-Gaussian fat tails due to intermittency.

Experimental results align with Kolmogorov (K41) and Obukhov–Kolmogorov (KO62) theories.

Abstract

We investigated turbulence in atomic Bose-Einstein condensates (BECs) using a minimally destructive, impurity injection technique analogous to particle image velocimetry in conventional fluids. Our approach transfers small regions of the BEC into a different hyperfine state, and tracks their displacement ultimately yielding the velocity field. This allows us to quantify turbulence in the same way as conventional in fluid dynamics in terms of velocity-velocity correlation functions called velocity structure functions that obey a Kolmogorov scaling law. Furthermore the velocity increments show a clear fat-tail non-Gaussian distribution that results from intermittency corrections to the initial "K41" Kolmogorov theory. Our observations are fully consistent with the later "KO62" description. These results are validated by a 2D dissipative Gross-Pitaevskii simulation.