Two-stream instability in quasi-one-dimensional Bose-Einstein condensates

TL;DR

This paper predicts a two-stream instability in elongated Bose-Einstein condensates using a kinetic Wigner formalism, identifying key parameters and regimes where instability occurs, relevant for experimental observation.

Contribution

It introduces a kinetic model based on the Wigner formalism to analyze two-stream instability in quasi-one-dimensional Bose-Einstein condensates, highlighting new instability regimes and parameter dependencies.

Findings

Unstable Bogoliubov waves can be excited in counterpropagation configurations.

A dimensionless Mach number parameter tunes stability regimes.

Estimated parameters for experimental observation of the instability.

Abstract

We apply a kinetic model to predict the existence of an instability mechanism in elongated Bose-Einstein condensates. Our kinetic description, based on the Wigner formalism, is employed to highlight the existence of unstable Bogoliubov waves that may be excited in the counterpropagation configuration. We identify a dimensionless parameter, the Mach number at T = 0, that tunes different regimes of stability. We also estimate the magnitude of the main parameters at which two-stream instability is expected to be observed under typical experimental conditions.