Optical-plug-assisted spin vortex in a ⁸⁷Rb dipolar spinor Bose-Einstein condensate

Generating a spin vortex in a ⁸⁷Rb dipolar spinor Bose-Einstein condensate in a controllable way is still experimentally challenging. We propose an experimentally easy and tunable way to produce spin vortex by varying the potential barrier height and the width of an additionally applied optical plug. A topological phase transition occurs from the trivial single mode approximation phase to the optical-plug-assisted-vortex one, as the barrier height increases and the width lies in an appropriate range. The optical plug causes radial density variation thus the spin vortex is favored by signifificantly lowering the intrinsic magnetic dipolar energy. A type of coreless spin vortex, difffferent from the conventional polar core vortex, is predicted by our numerical results. Our proposal removes a major obstacle to investigate the topological phase transition in a ⁸⁷Rb dipolar spinor BEC.