Quantum Statistical Behaviors of Interaction of an Atomic Bose-Einstein Condensate with Laser

We have investigated quantum statistical behaviors of photons and atoms in interaction of an atomic Bose-Einstein condensate with quantized laser field. When the quantized laser field is initially prepared in a superposition state which exhibits holes in its photon-numberdistribution, while the atomic field is initially in a Fock state,it is found that there is energy exchange between photons and atoms.For the input and output states, the photons and atoms may exhibit thesub-Poissonian distribution. The input and output laser fields mayexhibit quadrature squeezing, but for the atomic field, only the outputstate exhibits quadrature squeezing. It is shown that there exists theviolation of the Cauchy-Schwartz inequality, which means that thecorrelation between photons and atoms is nonclassical.