Topological interfaces crossed by defects and textures of continuous and discrete point group symmetries in spin-2 Bose-Einstein condensates

TL;DR

This paper constructs and analyzes topological defects and textures at interfaces between different magnetic phases in spin-2 Bose-Einstein condensates, revealing complex vortex structures and non-Abelian phenomena.

Contribution

It provides a systematic analytical framework for defects across phase interfaces in spin-2 BECs, including novel non-Abelian vortices and monopole-like boojums, supported by numerical simulations.

Findings

Identification of continuous and discrete topological defects at phase interfaces

Discovery of non-Abelian vortices and composite defect cores

Numerical evidence of complex defect structures and boojums

Abstract

We systematically and analytically construct a set of spinor wave functions representing defects and textures that continuously penetrate interfaces between coexisting, topologically distinct magnetic phases in a spin-2 Bose-Einstein condensate. These include singular and nonsingular vortices carrying mass or spin circulation that connect across interfaces between biaxial- and uniaxial nematic, cyclic and ferromagnetic phases, as well as vortices terminating as monopoles on the interface ("boojums"). The biaxial-nematic and cyclic phases exhibit discrete polytope symmetries featuring non-Abelian vortices and we investigate a pair of non-commuting line defects within the context of a topological interface. By numerical simulations, we characterize the emergence of non-trivial defect core structures, including the formation of composite defects. Our results demonstrate the potential of spin-2 Bose-Einstein condensates as experimentally accessible platforms for exploring interface physics, offering a wealth of combinations of continuous and discrete symmetries.