Josephson Effect Between Condensates with Different Internal Structures

We derive a general formula for Josephson current in a wide class of hybrid junctions between different internal structures on the basis of the Andreev-reflection picture. The formula extends existing formulae and also enables us to analyze novel hybrid junctions, such as B-phase/A-phase/B-phase (BAB) junctions in superfluid ³He systems which are accessible to experiments. It is predicted that BAB junctions will exhibit two types of current-phase relations associated with different internal symmetries. A "pseudo-magnetic interface effect" inherent in the system is also revealed.