Watching Dark Solitons Decay into Vortex Rings in a Bose-Einstein Condensate

TLDR

The authors generate dark solitons in two‑component Bose‑Einstein condensates by embedding a soliton in one component while filling its nodal plane with the second component, and then selectively removing the filling to trigger dynamical instabilities. The filled solitons remain stable for hundreds of milliseconds, but when the filling is removed they decay into stable vortex rings in a spherically symmetric trap, which the authors successfully imaged.

Abstract

We have created spatial dark solitons in two-component Bose-Einstein condensates in which the soliton exists in one of the condensate components and the soliton nodal plane is filled with the second component. The filled solitons are stable for hundreds of milliseconds. The filling can be selectively removed, making the soliton more susceptible to dynamical instabilities. For a condensate in a spherically symmetric potential, these instabilities cause the dark soliton to decay into stable vortex rings. We have imaged the resulting vortex rings.