Quantum-interference effects on the superposition of N displaced number states

We describe properties of a quantum system prepared in a superposition of N displaced number states, with emphasis on the interference effects among t he state components. Explicit expressions for wavefunctions in the coordina te and Fock-state representations, photon number distribution, variances an d quantum correlation coefficient of the quadrature operators, and quasipro bability distributions are calculated in detail. Nonclassical effects due t o such interference and the analogy with diffraction patterns arising in an N slit Young-type experiment are the main results in the present work. In particular, we show that interference and correlation effects in phase spac e are connected with the nondiagonal term of the quasiprobability distribut ions, providing further insight into the phenomenon. (C) 2001 Elsevier Scie nce B.V. All rights reserved.