Rotating quantum wave turbulence

TL;DR

This paper investigates rotating quantum turbulence, demonstrating energy transfer across scales via inertial and Kelvin waves, revealing a new turbulence regime in quantum fluids distinct from classical turbulence.

Contribution

It extends wave turbulence theory to quantum fluids, showing energy cascades and Kelvin-wave cascades at microscopic scales, supported by experiments and simulations.

Findings

Energy transfer from large to small scales observed

Kelvin-wave cascade identified at low temperatures

Boundary layer differs from classical Ekman layer

Abstract

Rotating turbulence is ubiquitous in nature. Previous works suggest that such turbulence could be described as an ensemble of interacting inertial waves across a wide range of length scales. For turbulence in macroscopic quantum condensates, the nature of the transition between the quasiclassical dynamics at large scales and the corresponding dynamics at small scales, where the quantization of vorticity is essential, remains an outstanding unresolved question. Here we expand the paradigm of wave-driven turbulence to rotating quantum fluids where the spectrum of waves extends to microscopic scales as Kelvin waves on quantized vortices. We excite inertial waves at the largest scale by periodic modulation of the angular velocity and observe dissipation-independent transfer of energy to smaller scales and the eventual onset of the elusive Kelvin-wave cascade at the lowest temperatures. We further find that energy is pumped to the system through a boundary layer distinct from the classical Ekman layer and support our observations with numerical simulations. Our experiments demonstrate a new regime of turbulent motion in quantum fluids where the role of vortex reconnections can be neglected, thus stripping the transition between the classical and the quantum regimes of turbulence down to its bare bones.