Controlled generation and manipulation of vortex dipoles in a   Bose-Einstein condensate
  We propose methods to generate and manipulate vortex dipoles in a Bose-Einstein condensate using Gaussian beams of red or blue-detuned laser. Velocity-controlled vortex dipoles are shown to be created and launched by a red-detuned beam and by two blue-detuned beams. Critical velocities for the vortex nucleation are investigated. The launched vortex dipoles can be trapped, curved, accelerated, and decelerated using Gaussian beams. Collisions between vortex dipoles are demonstrated. 
Tomohiko Aioi, Tsuyoshi Kadokura, Tetsuo Kishimoto, Hiroki Saito
cond-mat.quant-gas