Velocity Statistics Distinguish Quantum Turbulence from Classical Turbulence

TL;DR

This paper demonstrates that velocity distributions in decaying quantum turbulence are markedly non-Gaussian with power-law tails, distinguishing them from classical turbulence, and attributes these features to vortex reconnection dynamics.

Contribution

It provides the first detailed analysis of velocity statistics in quantum turbulence, revealing non-Gaussian behavior and linking it to vortex reconnection events.

Findings

Velocity distributions have 1/v^3 power-law tails.

Quantum turbulence differs from classical turbulence in velocity statistics.

Vortex reconnections produce the observed power-law tails.

Abstract

By analyzing trajectories of solid hydrogen tracers, we find that the distributions of velocity in decaying quantum turbulence in superfluid $^4$He are strongly non-Gaussian with $1/v^3$ power-law tails. These features differ from the near-Gaussian statistics of homogenous and isotropic turbulence of classical fluids. We examine the dynamics of many events of reconnection between quantized vortices and show by simple scaling arguments that they produce the observed power-law tails.