Universal Critical Behavior at a Phase Transition to Quantum Turbulence

TL;DR

This paper demonstrates that the onset of quantum turbulence exhibits universal critical behavior, belonging to the directed percolation class, revealing deep connections between quantum and classical non-equilibrium phase transitions.

Contribution

It uncovers the universal critical scaling laws at the transition to quantum turbulence and links it to the directed percolation universality class, highlighting the role of quantum vortices.

Findings

Transition to quantum turbulence belongs to directed percolation universality class

Universal scaling laws are observed at the onset of quantum turbulence

Quantum vortices are crucial in the critical behavior

Abstract

Turbulence is one of the most prototypical phenomena of systems driven out of equilibrium. While turbulence has been studied mainly with classical fluids like water, considerable attention is now drawn to quantum turbulence (QT), observed in quantum fluids such as superfluid helium and Bose-Einstein condensates. A distinct feature of QT is that it consists of quantum vortices, by which turbulent circulation is quantized. Yet, under strong forcing, characteristic properties of developed classical turbulence such as Kolmogorov's law have also been identified in QT. Here, we study the opposite limit of weak forcing, i.e., the onset of QT, numerically, and find another set of universal scaling laws known for classical non-equilibrium systems. Specifically, we show that the transition belongs to the directed percolation universality class, known to arise generically in transitions into an absorbing state, including transitions to classical shear-flow turbulence after very recent studies. We argue that quantum vortices play an important role in our finding.