Tests of Bose-broken Symmetry in Atomic Bose-Einstein Condensates
  We present an elementary model of the collapses and revivals in the visibility of the interference between two atomic Bose-Einstein condensates. We obtain different predictions of the revival times whether we conserve or break atom number conservation from the outset. The validity of Bose-broken symmetry can be tested by observations of these collapses and revivals. 
T. Wong, M. J. Collett, S. M. Tan, D. F. Walls, and E. M. Wright