Nonlocal energy transfer mechanism in three-dimensional quantum turbulence

TL;DR

This paper uncovers a universal nonlocal energy transfer mechanism in three-dimensional quantum turbulence, revealing how energy bypasses classical cascades through vortex alignment and scale separation, leading to nonclassical spectra.

Contribution

It introduces a novel nonlocal energy transfer process in quantum turbulence, supported by theoretical analysis and large-scale numerical simulations.

Findings

Energy transfers directly from large to small scales.

The mechanism bypasses classical Kolmogorov cascade.

Results show nonclassical energy spectra in quantum turbulence.

Abstract

We investigate the kinetic energy cascade in zero-temperature quantum turbulence. Using simple theoretical arguments and unprecedented numerical simulations, we unveil an universal mechanism transferring energy directly from large to very small scales, thus bypassing the Kolmogorov-like local energy cascade and resulting in nonclassical energy spectra. This mechanism rests both on the vast separation of scales typical of superfluid helium-4 flows and on the alignment between quantum vortices and large-scale velocity gradients, in direct analogy with vortex stretching in classical flows.