Superfluid Turbulence: Nonthermal Fixed Point in an Ultracold Bose Gas

TL;DR

This paper investigates nonthermal fixed points in ultracold Bose gases, revealing universal power-law behaviors linked to vortex dynamics and superfluid turbulence, with implications for fundamental physics and related phenomena.

Contribution

It connects nonthermal fixed points to vortex excitations and turbulence in Bose gases, providing a unified interpretation of momentum scaling in these systems.

Findings

Universal power-law distributions are related to vortex dynamics.

Long-wavelength excitations follow a non-thermal power law.

Results have implications for early-universe and quark-gluon plasma phenomena.

Abstract

Nonthermal fixed points of far-from-equilibrium dynamics of a dilute degenerate Bose gas are analysed in two and three spatial dimensions. For such systems, universal power-law distributions, previously found within a nonperturbative quantum-field theoretic approach, are shown to be related to vortical dynamics and superfluid turbulence. The results imply an interpretation of the momentum scaling at the nonthermal fixed points in terms of independent vortex excitations of the superfluid. Long-wavelength acoustic excitations on the top of these are found to follow a non-thermal power law. The results shed light on fundamental aspects of superfluid turbulence and have strong potential implications for related phenomena studied, e.g., in early-universe inflation or quark-gluon plasma dynamics.