Collisions of solitons and vortex rings in cylindrical Bose-Einstein condensates

TL;DR

This paper investigates the head-on collisions of solitons and vortex rings in cylindrical Bose-Einstein condensates, revealing elastic and inelastic behaviors depending on density and velocity, and explaining these phenomena with dispersion diagrams.

Contribution

It provides the first detailed simulation study of solitary wave collisions in cylindrical BECs, highlighting conditions for elastic and inelastic interactions and connecting results to experimental observations.

Findings

Slow vortex rings and fast solitons collide elastically.

Inelastic collisions occur at higher densities and intermediate velocities.

Inelastic collisions produce shell-like structures that decay into depletion droplets.

Abstract

Interactions of solitary waves in a cylindrically confined Bose-Einstein condensate are investigated by simulating their head-on collisions. Slow vortex rings and fast solitons are found to collide elastically contrary to the situation in the three-dimensional homogeneous Bose gas. Strongly inelastic collisions are absent for low density condensates but occur at higher densities for intermediate velocities. The scattering behaviour is rationalised by use of dispersion diagrams. During inelastic collisions, spherical shell-like structures of low density are formed and they eventually decay into depletion droplets with solitary wave features. The relation to similar shells observed in a recent experiment [Ginsberg et al. Phys Rev. Lett. 94, 040403 (2005)] is discussed.