The Schrodinger Cat Family in Attractive Bose Gases and Their   Interference
  We show that the ground state of an attractive Bose gas in a double well evolves from a coherent state to a Schrodinger Cat like state as the tunneling barrier is decreased. The latter exhibits super- fragmentation as spin-1 Bose gas with antiferromagnetic interaction, which is caused by the same physics. We also show that the fragmented condensates of attractive and repulsive Bose gases in double wells lead to very different interference patterns. 
Tin-Lun Ho and C. V. Ciobanu