Transition to quantum turbulence in a finite size superfluid

TL;DR

This paper investigates the transition to quantum turbulence in finite-size superfluids like trapped bosonic atoms, using experiments with $^{87} ext{Rb}$ BECs to characterize vortex formation and propose a model for the observed crossover.

Contribution

It introduces the concept of quantum turbulence in finite superfluids and provides experimental evidence and a simple model for the transition process.

Findings

Transition to turbulence is a gradual crossover with a sharp enough change.

Vortex lines formation characterizes the turbulent regime.

An effective critical line separates turbulent and non-turbulent regimes.

Abstract

A novel concept of quantum turbulence in finite size superfluids, such as trapped bosonic atoms, is discussed. We have used an atomic $^{87}\mathrm{Rb}$ BEC to study the emergence of this phenomenon. In our experiment, the transition to the quantum turbulent regime is characterized by a tangled vortex lines formation, controlled by the amplitude and time duration of the excitation produced by an external oscillating field. A simple model is suggested to account for the experimental observations. The transition from the non-turbulent to the turbulent regime is a rather gradual crossover. But it takes place in a sharp enough way, allowing for the definition of an effective critical line separating the regimes. Quantum turbulence emerging in a finite-size superfluid may be a new idea helpful for revealing important features associated to turbulence, a more general and broad phenomenon.