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We investigate the entanglement swapping of the continuous variable states by taking the pair Schrödinger cat states as the input entangled states, in which the two-mode squeezed vacuum and the pair cat states serve as the quantum channel, respectively. The entanglement of the initial states as well as the final states is analyzed by adopting the logarithmic negativity as the measure of entanglement. The quantum teleportation task by exploiting the swapped states as the quantum channel is also considered, where a coherent state serves as the target state and the average fidelity is examined. [ABSTRACT FROM AUTHOR]

The stationary entanglement and Bell violation of two qubits collectively interacting with a common thermal reservoir is investigated, and the analytical relations among average thermal photon number of the reservoir, entanglement and Bell violation of two qubits are given in detail. The initial fraction of Bell singlet state determines whether the common thermal reservoir can enhance the entanglement of two qubits or not in this case. Moreover, the stationary maximally entangled mixed state can emerge in the collective decay of two qubits in a thermal reservoir at zero-temperature only if the fraction of Bell singlet state in the initial state is not smaller than 2/3. Furthermore, it is shown that the collective decay can induce the entanglement of two qutrits initially in the maximally mixed state, and induce distillable entanglement from bound entangled states. [ABSTRACT FROM AUTHOR]

We investigate the entanglement of two two-mode two-photon Jaynes–Cummings models in the presence of phase decoherence. We find an explicit analytical solution of the system and discuss the influence of the phase decoherenc on the entanglement dynamics. Our results shows that the entanglement of the two initially entangled atoms can remain zero for a finite time and revive later. However, if the phase decoherence is taken into accounted, the entanglement cannot revive completely. [ABSTRACT FROM AUTHOR]

We investigate the mutual information and entanglement of stationary states of two locally driven qubits under the influence of collective dephasing. It is shown that both the mutual information and the entanglement of two qubits in the stationary state exhibit damped oscillation with the scaled action time γT of the local external driving field. It means that we can control both the entanglement and total correlation of the stationary state of two qubits by adjusting the action time of the driving field. We also consider the influence of collective dephasing on the entanglement of two qutrits and obtain the sufficient condition that the stationary state is entangled. [ABSTRACT FROM AUTHOR]

The mathematical and physical properties of the states which are generated by excitations on the coherent state of a harmonic oscillator in a finite-dimensional Hilbert space are studied. It is shown that the state exhibits squeezing in one of the quadratures of the field and sub-Poissonian photon statistics. [ABSTRACT FROM AUTHOR]

The system of a three-level atom in the ξ configuration coupled to two quantized field modes with arbitrary detuning and density-dependent multiphoton interaction is studied by dynamical algebraic method. With the help of an su(3) algebraic structure, we diagonalize the Hamiltonian by making use of unitary transformations and obtain the eigenvalues, eigenstates and time evolution operator for the system. Based on this su(3) structure, we also show that the system of a three-level atom in the ξ configuration can be exactly transformed to an effective two-level Hamiltonian by an unitary transformation. Finally, we show that there exist an su(N) algebraic structure in the system of a N-level atom interacting with N - 1 field modes. [ABSTRACT FROM AUTHOR]