Spin-vortex nucleation in a Bose-Einstein condensate by a spin-dependent rotating trap

A method to produce a spin-dependent rotating potential using near-resonant circularly polarized laser beams is proposed. It is shown that half-quantum vortices are nucleated in a spinor Bose-Einstein condensate with an antiferromagnetic interaction. In contrast to the vortex nucleation in a scalar BEC, the spin-vortex nucleation occurs at a low rotation frequency ($\simeq 0.1 \omega_\perp$ with $\omega_\perp$ being the radial trap frequency) in a short nucleation time $\simeq 50$ ms without dissipation. A method for nondestructive measurement of half-quantum vortices is discussed.