Quantum Elliptic Vortex in a Nematic-Spin Bose-Einstein Condensate

We find a novel topological defect in a spin-nematic superfluid theoretically. A quantized vortex spontaneously breaks its axisymmetry, leading to an elliptic vortex in nematic-spin Bose-Einstein condensates with small positive quadratic Zeeman effect. The new vortex is considered the Joukowski transform of a conventional vortex. Its oblateness grows when the Zeeman length exceeds the spin healing length. This structure is sustained by balancing the hydrodynamic potential and the elasticity of a soliton connecting two spin spots, which are observable by in situ magnetization imaging. The theoretical analysis clearly defines the difference between half quantum vortices of the polar and antiferromagnetic phases in spin-1 condensates.

Automated summary

A novel topological defect, an elliptic vortex, has been identified theoretically in a spin-nematic superfluid under specific conditions. This new vortex structure, considered a Joukowski transform of a conventional vortex, is characterized by its oblateness and its dependence on the Zeeman and spin healing lengths. The theoretical analysis also clarifies the distinction between half quantum vortices in polar and antiferromagnetic phases in spin-1 condensates.