Distortion of Interference Fringes and the Resulting Vortex Production of Merging Bose-Einstein Condensates

TL;DR

This paper explores how interactions and expansion influence interference fringe distortion in merging Bose-Einstein condensates, leading to vortex formation, with a focus on identifying regimes and optimal conditions for vortex creation.

Contribution

It provides a detailed numerical analysis of the regimes of interference and vortex formation in BECs, identifying key parameters and conditions for dynamical instabilities.

Findings

Distortion of fringes depends on velocity and density.

Three regimes: collision, expansion, merging.

Optimal parameters for vortex creation are identified.

Abstract

We investigate the effects of interatomic interactions and expansion on the distortion of interference fringes of a pair of initially well-separated, but coherent, condensate clouds trapped in a harmonic trap. The distortion of interference fringes, which can lead to the spontaneous formation of vortices in the atom clouds, depends crucially on two relevant parameters: the center-of-mass velocity and peak density of the initial state. We identify three qualitatively distinct regimes for the interfering condensates: collision, expansion, and merging, by the spatial and temporal features of the fringe spacings. Using a comprehensive set of numerical simulations based on the Gross-Pitaevskii equation, we specify the cross-overs between these regimes and propose the optimal the system parameters required for dynamical instabilities and vortex creation.