Spinor Bose-Einstein condensate flow past an obstacle

TL;DR

This paper investigates the complex flow dynamics of a spinor Bose-Einstein condensate around obstacles, revealing multiple sound speeds and the formation of nonlinear structures like solitons and vortices through numerical simulations.

Contribution

It introduces the analysis of two sound speeds in spinor condensates and demonstrates the nucleation of nonlinear structures during obstacle-induced flow, expanding understanding of spinor BEC dynamics.

Findings

Identification of two sound speeds in spinor BECs.

Nucleation of dark solitons and vortex pairs at supercritical speeds.

Formation of vortex rings in higher-dimensional flows.

Abstract

We study the flow of a spinor (F=1) Bose-Einstein condensate in the presence of an obstacle. We consider the cases of ferromagnetic and polar spin-dependent interactions and find that the system demonstrates two speeds of sound that are identified analytically. Numerical simulations reveal the nucleation of macroscopic nonlinear structures, such as dark solitons and vortex-antivortex pairs, as well as vortex rings in one- and higher-dimensional settings respectively, when a localized defect (e.g., a blue-detuned laser beam) is dragged through the spinor condensate at a speed larger than the second critical speed.