Two-way quantum communication: Generalization of secure quantum information exchange to quantum network

[摘要] The idea of secure quantum information exchange (SQIE) [{it J. Phys. B: At. Mol. Opt. Phys.} 44, 115504 (2011)] is introduced for the secure exchange of single qubit information states between two legitimate users, Alice and Bob. In the present paper, we extend this original SQIE protocol by presenting a scheme, which enables the secure exchange of n-single qubit information states among the n nodes of a quantum network, with the aid of a special kind of 4$n$-qubit entangled state and the classical assistance of an extra participant Charlie. For experimental realization of our extended SQIE protocol, we suggest an efficient scheme for the generation of a special kind of 4n-qubit entangled state using the interaction between highly detuned $Lambda$-type three-level atoms and optical coherent field. Further, by discussing the various experimental parameters, we show that the special kind 4$n$-qubit entangled state can be generated with the presently available technology.

[学科分类] 物理（综合）

[关键词] Quantum information;quantum teleportation;two-way quantum communication;coherent state;QED.