Enhancement of damping in a turbulent atomic Bose-Einstein condensate

TL;DR

This study demonstrates that turbulence in a superfluid Bose-Einstein condensate significantly increases damping of collective oscillations, revealing enhanced momentum transport analogous to classical fluid viscosity.

Contribution

It introduces a method to measure turbulence-induced damping in a BEC, showing how turbulence amplifies collective mode damping beyond Landau predictions.

Findings

Damping exceeds Landau rate in turbulent BECs

Turbulence enhances energy transfer to collective modes

Damping serves as a probe for superfluid turbulence

Abstract

Turbulence enhances momentum transport in classical fluids, effectively increasing their viscosity. We investigate an analogous effect in a superfluid by measuring the damping of collective oscillations in an atomic Bose-Einstein condensate (BEC) containing stationary spin-superflow turbulence. Using continuous spin driving to maintain turbulence in a spin-1 $^{23}$Na BEC, we excite its quadrupole mode and measure the damping rate over a range of temperatures. The damping consistently exceeds the Landau-damping rate expected for an equilibrium, non-turbulent BEC. The enhancement likely originates from two complementary processes: direct energy transfer from the mode to turbulent condensate fluctuations and turbulence-induced modification of the thermal cloud that amplifies Landau damping. These results establish collective-mode damping as a sensitive probe of momentum transport in superfluid turbulence.