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We study the dynamical properties of a cavity¯eld coupling to a Cooper pair box (CPB). We assumed that the CPB is prepared initially in a mixed state with a coherent state for the¯eld. By solving the time-dependent equations using the evolution operator, it shows that mean numbers of Cooper pairs is a®ected by the detuning. The mean number of Cooper pairs is further enhanced by the multi-photon processes in commonly used cavity¯eld.

In this contribution, we investigate the bipartite non-classical correlations (NCCs) of a system formed by two nitrogen-vacancy (N-V) centers placed in two spatially separated single-mode nanocavities inside a planar photonic crystal (PC). The physical system is mathematically modeled by time-dependent Schrödinger equation and analytically solved. The bipartite correlations of the two N-V centers and the two-mode cavity have been analyzed by skew information, log-negativity, and Bell function quantifiers. We explore the effects of the coupling strength between the N-V-centers and the cavity fields as well as the cavity-cavity hopping constant and the decay rate on the generated correlation dynamics. Under some specific parameter values, a large amount of quantum correlations is obtained. This shows the possibility to control the dynamics of the correlations for the NV-centers and the cavity fields.

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We study the interaction of the single-Cooper pairbox interacting with a cavity field. The solution of the system dynamics is obtained. The entropy as a measure of the entanglement between the qubit and the field is calculated and compared with the field purity. It is shown that the general behavior of the entropy as well as the field purity is affected in the same way under different values of the system parameters.