Quantum Dynamics of Coupled Bosonic Wells within the Bose-Hubbard   Picture
  We relate the quantum dynamics of the Bose-Hubbard model (BHM) to the semiclassical nonlinear equations that describe an array of interacting Bose condensates by implementing a standard variational procedure based on the coherent state method. We investigate the dynamics of the two-site BHM from the purely quantum viewpoint by recasting first the model within a spin picture and using then the related dynamical algebra. The latter allows us to study thoroughly the energy spectrum structure and to interpret quantally the classical symmetries of the two-site dynamics. The energy spectrum is also evaluated through various approximations relying on the coherent state approach. 
R. Franzosi (1), V. Penna (2), R. Zecchina (3) ((1)Pisa University,   Italy, (2)Turin Politecnico, Italy, (3)ICTP, Trieste, ...