  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.
