Superfluid Turbulence: Nonthermal Fixed Point in an Ultracold Bose Gas

Understand

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.