Macroscopic quantum self-trapping and atomic tunneling in two-species Bose-Einstein condensates - art. no. 023604

We present a theoretical treatment of macroscopic quantum self-trapping (MQ ST) and quantum coherent atomic tunneling in a zero-temperature two-species Bose-Einstein condensate system in the presence of the nonlinear self-inte raction of each species, the interspecies nonlinear interaction, and the Jo sephson-like tunneling interaction. It is shown that the nonlinear interact ions can dramatically affect the MQST and the atomic tunneling, and lead to the collapses and revivals (CR) of the population imbalance between the tw o condensates. The competing effects between the self-interaction of each s pecies and the interspecies interaction can lead to a quenching of the MQST and a suppression of the CR and the Shapiro-like steps of the atomic tunne ling current. It is revealed that interatomic nonlinear interactions can in duce coherent atomic tunneling between two condensates even though interspe cies Josephson-like tunneling coupling does not exist.