Small-scale universality of particle dynamics in quantum turbulence

Abstract

We show that, in turbulent two-fluid flows of superfluid $^{4}\mathrm{He}$, the statistically described dynamics of small particles suspended in the liquid does not depend on the type of imposed flow, at scales smaller than the average distance between quantized vortices, the quantum length scale of the flow. More precisely, regardless of the mechanically or thermally driven nature of the large-scale flow, the tails of the observed particle velocity statistical distributions, indicating the occurrence of large-magnitude events in the proximity of quantized vortices, display the same power-law shape, characteristic of the quantum description of superfluid $^{4}\mathrm{He}$. This property of quantum turbulence can be linked to the small-scale universality observed in classical turbulent flows of viscous fluids.