Husimi distribution and phase-space analysis of a vibron-model quantum phase transition

摘要

The Husimi distribution is proposed for a phase-space analysis of quantum phase transitions in the twodimensionalnU(3) vibron model for N-size molecules. We show that the inverse participation ratio and Wehrl’snentropy of the Husimi distribution give sharp signatures of the quantum (shape) phase transition from linearnto bent. Numerical results are complemented with a variational approach using parity-symmetry-adapted U(3)ncoherent states, which reach the minimum Wehrl entropy N(3+2N)n(N+1)(N+2) , in the rigidly linear phase, according tona generalized Wehrl-Lieb conjecture. We also propose a characterization of the vibron-model quantum phasentransition by means of the zeros of the Husimi distribution.