Stabilization of Solitons Generated by a Supersonic Flow of Bose-Einstein Condensate Past an Obstacle

TL;DR

This paper investigates how dark solitons generated by a supersonic Bose-Einstein condensate flow become effectively stable due to a transition from absolute to convective instability at a critical flow velocity, explaining observed numerical stability.

Contribution

It identifies the critical flow velocity at which dark solitons transition from absolute to convective instability, leading to their effective stabilization.

Findings

Dark solitons become effectively stable beyond a critical flow velocity.

Transition from absolute to convective instability occurs at a specific flow speed.

Numerical simulations confirm the stability mechanism.

Abstract

Stability of dark solitons generated by a supersonic flow of Bose-Einstein condensate past an obstacle is investigated. It is shown that in the reference frame attached to the obstacle a transition occurs at some critical value of the flow velocity from absolute instability of dark solitons to their convective instability. This leads to decay of disturbances of solitons at fixed distance from the obstacle and formation of effectively stable dark solitons. This phenomenon explains surprising stability of the flow picture that has been observed in numerical simulations.