We investigate continuous variable entanglement produced in two distant coupled cavities, in which two four-level atoms are driven by classical fields respectively. Under the large detuning condition, an effective Ham...We investigate continuous variable entanglement produced in two distant coupled cavities, in which two four-level atoms are driven by classical fields respectively. Under the large detuning condition, an effective Hamiltonian containing the square of the creation （annihilation） operator of the cavity field is derived. Due to the nonlinearity, entanglement formally created by the beam splitter type interaction is transformed into the nondegenerate parametric down conversion type. Employing the operator algebraic method, we study the time evolution of the entanglement condition, and show that the system provides us an advantage in achieving a larger photon number with better entanglement. We also discuss the dissipation of the cavities affecting the entanglement.展开更多
A quantum teleportation scheme to teleport a kind of tripartite entangled states of continuous variables by using a quantum channel composed of three bipartite entangled states is proposed. The joint Bell measurement ...A quantum teleportation scheme to teleport a kind of tripartite entangled states of continuous variables by using a quantum channel composed of three bipartite entangled states is proposed. The joint Bell measurement is feasible because the bipartite entangled states are complete and the squeezed state has a natural representation in the entangled state basis. The calculation is greatly simplified by using the Schmidt decomposition of the entangled states.展开更多
In this paper security of the quantum key distribution scheme using correlations of continuous variable Einstein- Podolsky-Rosen （EPR） pairs is investigated. A new approach for calculating the secret information ra...In this paper security of the quantum key distribution scheme using correlations of continuous variable Einstein- Podolsky-Rosen （EPR） pairs is investigated. A new approach for calculating the secret information rate △I is proposed by using the Shannon information theory. Employing an available parameter F which is associated with the entanglement of the EPR pairs, one can detect easily the eavesdropping. Results show that the proposed scheme is secure against individual bearn splitter attack strategy with a proper squeeze parameter.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 11074028)
文摘We investigate continuous variable entanglement produced in two distant coupled cavities, in which two four-level atoms are driven by classical fields respectively. Under the large detuning condition, an effective Hamiltonian containing the square of the creation （annihilation） operator of the cavity field is derived. Due to the nonlinearity, entanglement formally created by the beam splitter type interaction is transformed into the nondegenerate parametric down conversion type. Employing the operator algebraic method, we study the time evolution of the entanglement condition, and show that the system provides us an advantage in achieving a larger photon number with better entanglement. We also discuss the dissipation of the cavities affecting the entanglement.
文摘A quantum teleportation scheme to teleport a kind of tripartite entangled states of continuous variables by using a quantum channel composed of three bipartite entangled states is proposed. The joint Bell measurement is feasible because the bipartite entangled states are complete and the squeezed state has a natural representation in the entangled state basis. The calculation is greatly simplified by using the Schmidt decomposition of the entangled states.
基金Project supported by the National Natural Science Foundation of China （Grant No 60472018）.
文摘In this paper security of the quantum key distribution scheme using correlations of continuous variable Einstein- Podolsky-Rosen （EPR） pairs is investigated. A new approach for calculating the secret information rate △I is proposed by using the Shannon information theory. Employing an available parameter F which is associated with the entanglement of the EPR pairs, one can detect easily the eavesdropping. Results show that the proposed scheme is secure against individual bearn splitter attack strategy with a proper squeeze parameter.
