Phase structure of a two-fluid bosonic system
  The phase diagram of a two-fluid bosonic system is investigated. The proton-neutron interacting boson model (IBM-2) possesses a rich phase structure involving three control parameters and multiple order parameters. The surfaces of quantum phase transition between spherical, axially-symmetric deformed, and SU*(3) triaxial phases are determined, and the evolution of classical equilibrium properties across these transitions is investigated. Spectroscopic observables are considered in relation to the phase diagram. 
M. A. Caprio, F. Iachello