Spinor Bose Condensates in Optical Traps

TL;DR

This paper explores the properties and vortex stability of spinor Bose-Einstein condensates in optical traps, highlighting differences between ferromagnetic and polar states based on atomic species.

Contribution

It provides a theoretical analysis of the ground states and vortex stability in spin-1 Bose condensates, emphasizing the role of scattering lengths and spin character.

Findings

Polar state stable with ordinary vortices

Ferromagnetic state stable with unit circulation vortices

Presence of coreless (Skyrmion) vortices in ferromagnetic state

Abstract

In an optical trap, the ground state of spin-1 Bosons such as $^{23}$Na, $^{39}$K, and $^{87}$Rb can be either a ferromagnetic or a "polar" state, depending on the scattering lengths in different angular momentum channel. The collective modes of these states have very different spin character and spatial distributions. While ordinary vortices are stable in the polar state, only those with unit circulation are stable in the ferromagnetic state. The ferromagnetic state also has coreless (or Skyrmion) vortices like those of superfluid $^{3}$He-A. Current estimates of scattering lengths suggest that the ground states of $^{23}$Na and $^{87}$Rb condensate are a polar state and a ferromagnetic state respectively.