Observation of Topologically Stable 2D Skyrmions in an Antiferromagnetic Spinor Bose-Einstein Condensate

TLDR

The study creates and follows the time evolution of two‑dimensional Skyrmion excitations in an antiferromagnetic spinor Bose‑Einstein condensate, and examines the potential emergence of half‑quantum vortices during their deformation. A spin‑rotation technique imprints topologically protected Skyrmion spin textures onto a sodium condensate in the polar phase. The Skyrmion remains stable for a few tens of milliseconds before dynamically deforming and eventually decaying into a uniform spin texture, a process that breaks the polar phase inside the condensate without allowing topological charge density to flow through the sample boundary.

Abstract

We present the creation and time evolution of two-dimensional Skyrmion excitations in an antiferromagnetic spinor Bose-Einstein condensate. Using a spin rotation method, the Skyrmion spin textures were imprinted on a sodium condensate in a polar phase, where the two-dimensional Skyrmion is topologically protected. The Skyrmion was observed to be stable on a short time scale of a few tens of ms but to dynamically deform its shape and eventually decay to a uniform spin texture. The deformed spin textures reveal that the decay dynamics involves breaking the polar phase inside the condensate without having topological charge density flow through the boundary of the finite-sized sample. We discuss the possible formation of half-quantum vortices in the deformation process.