Phase-slips and vortex dynamics in Josephson oscillations between   Bose-Einstein condensates
  We study the relation between Josephson dynamics and topological excitations in a dilute Bose-Einstein condensate confined in a double-well trap. We show that the phase slips responsible for the self-trapping regime are created by vortex rings entering and annihilating inside the weak-link region or created at the center of the barrier and expanding outside the system. Large amplitude oscillations just before the onset of self-trapping are also strictly connected with the dynamics of vortex rings at the edges of the inter-well barrier. Our results extend and analyze the dynamics of the vortex-induced phase slippages suggested a few decades ago in relation to the "ac" Josephson effect of superconducting and superfluid helium systems. 
Marta Abad, Muntsa Guilleumas, Ricardo Mayol, Francesco Piazza, Dora   M. Jezek, and Augusto Smerzi
cond-mat.quant-gas