Quantum coherence in a mesoscopic Josephson junction with dissipation - art. no. 024511

A mesoscopic Josephson junction in a superconducting ring enclosing a magne tostatic flux with dissipation is considered. The dissipation in this syste m is described as a consequence of its coupling to a reservoir. By solving the master equation it is shown that the state of the junction can evolve i nto a quantum superposition of two coherent states even when the dissipatio n is present. It is also shown that squeezing effects can exist in such a s ystem, and the dynamic behavior of the supercurrent shows collapse and revi val phenomena. The quantum decoherence is also discussed.