PhD Seminar - Topology and Geometry of Rotating Spinor Condensates: A Novel Kind of Topological Defects

In this presentation I will talk about the use of a formula known as the Riemann-Hurwitz formula for predicting a new kind of topological defects. I will show how these defects appear in rotating spinor condensates (Bose-condensates of atoms with a spin). When the system is rotating, the spins form skyrmion lattices, that can be pictured using mappings from the plane to the sphere that preserve area. I will show examples of two such mappings, describing a square lattice and a hexagonal lattice, and emphasize how the defects help in understanding them.

In addition, I will also address the impact of said defects on condensate flow. Notably, regions of depleted vorticity form around each defect, resulting in a lattice of "unvortices". This vorticity structure presents a striking contrast to the traditional vortex lattices observed in conventional rotating condensates.