  We employ a semiclassical picture to study dynamics in a bosonic Josephson
junction with various initial conditions. Phase-diffusion of coherent
preparations in the Josephson regime is shown to depend on the initial relative
phase between the two condensates. For initially incoherent condensates, we
find a universal value for the buildup of coherence in the Josephson regime. In
addition, we contrast two seemingly similar on-separatrix coherent
preparations, finding striking differences in their convergence to classicality
as the number of particles increases.
