Quantum phase transition in the U(3) boson system

The quantum phase transitional behavior of the U(3) boson model is studied. Low-lying levels, overlaps of wavefunctions with those in the d-wave dominant and s- and d-wave mixed phases, as well as ground state occupation probabilities of s- and d-components are examined as functions of the control parameter and the number of particles. The results indicated that the s- and d-wave component change in the wavefunction possibly is a first order quantum phase transition in the large N limit.