Penetration of a vortex dipole across an interface of Bose-Einstein   condensates
  The dynamics of a vortex dipole in a quasi-two dimensional two-component Bose-Einstein condensate are investigated. A vortex dipole is shown to penetrate the interface between the two components when the incident velocity is sufficiently large. A vortex dipole can also disappear or disintegrate at the interface depending on its velocity and the interaction parameters. 
Tomohiko Aioi, Tsuyoshi Kadokura, Hiroki Saito
cond-mat.quant-gas