  Interference is observed when two independent Bose-Einstein condensates
expand and overlap. This phenomenon is typical, in the sense that the
overwhelming majority of wave functions of the condensates, uniformly sampled
out of a suitable portion of the total Hilbert space, display interference with
maximal visibility. We focus here on the phases of the condensates and their
(pseudo) randomization, which naturally emerges when two-body scattering
processes are considered. Relationship to typicality is discussed and analyzed.
