Rényi entropy of the U(3) vibron model

Abstract

Renyi entropies and variances are determined in the vibron model. They provide a sharp detector for the quantum (shape) phase transition (from linear to bent) at the critical value ξc of a control parameter ξ. Numerical results are complemented and compared with a variational approximation in terms of parity-symmetry-adapted coherent (Schodinger’s catlike) states, which provide a good approximation to describe delocalization properties of the ground state of vibron models across the critical point for N-size molecules.