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.Fil: Abad, M.. Cnr - Istituto Nazionale Di Ottica; ItaliaFil: Guilleumas, M.. Institut de Nanociencia I Nanotecnologia; ItaliaFil: Mayol, R.. Institut de Nanociencia I Nanotecnologia; ItaliaFil: Piazza, F.. Universitat Technical Zu Munich; AlemaniaFil: Jezek, Dora Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Smerzi, A.. Cnr - Istituto Nazionale Di Ottica; Itali