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计新  李克  张寿 《中国物理》2006,15(3):478-481

We propose a scheme for teleporting a two-atom entangled state incavity quantum electrodynamics (QED). In the scheme, we choose asingle Einstein--Podolsky--Rosen (EPR) pair as the quantum channel whichis shared by the sender and the receiver. By using the atom--cavity-fieldinteraction and introducing an additional atom, we can teleportthe two-atom entangled state successfully with a probability of 1.0.Moreover, we show that the scheme is insensitive to cavity decayand thermal field.  相似文献   

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谭佳  方卯发 《中国物理》2006,15(11):2514-2517

We present a scheme to remotely prepare a photon--photon entangledstate via entanglement swapping in cavity QED. Using two successiveprocesses of appropriate atom--cavity interaction and subsequentmeasurements, we obtain the entangled state with certainprobability.  相似文献   

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陈志华  林秀敏 《中国物理》2005,14(9):1821-1824

An experimentally feasible scheme for implementing quantum secret sharing via cavity quantum electrodynamics （QED） is proposed. The scheme requires the large detuning of the cavity field from the atomic transition, the cavity is only virtually excited, thus the requirement on the quality factor of the cavity is greatly loosened.  相似文献   

    

ZHOUBang-Rong 《理论物理通讯》2004,42(1):79-82

It is shown that by means of canonical operator approach the Ward-Takahashi identity (WTI) at finite temperature T and finite chemical potential μ for complete vectorial vertex and complete fermion propagator can be simply proven, rigorously for Quantum Electrodynamics, and approximately for Quantum Chromodynamics, where the ghost effect in the fermion sector is neglected. The WTI shown in the real-time thermal matrix form will give definite thermal constraints on the imaginary part of inverse complete Feynman propagator including self-energy for fermion and will play an important role in relevant physical processes. When the above inverse propagator is assumed to be real, the thermal WTI will essentially be reduced to its form at T=μ=0 thus one can use it in the latter‘s form. At this point, a practical example is indicated.  相似文献   

    

ZHANGRong ZHUShi-Qun 《理论物理通讯》2004,42(2):197-200

A method to prepare multi-particle entanglement of Greenberger-Horne-Zeilinger-type and W-type is proposed through the interaction between the cavity and many atoms simultaneously . After suitable interaction, the selected measurements on the cavity field can create the entangled atomic states. These entangled states can be useful for quantum information manipulation and fundamental study of quantum theory. These states that violate the Bell‘s inequality are proven.  相似文献   

    

ZHENGShi-Biao 《理论物理通讯》2004,42(4):501-504

We describe the Greenberger-Horne-Zeilinger (GHZ) paradox in the multi-mode Schroedinger cat states.We also show that the multi-mode cat states violate the Bell‘s inequality by an amount that grows exponentially with number of modes. The test of quantum nonlocality is based on parity measurement and displacement operation, which are experimentally feasible. We also describe a scheme for the generation of the cat states in cavity QED.  相似文献   

    

ZHANG Wen-Hai DAI Jie-Lin YE Liu 《理论物理通讯》2008,49(6):1473-1476

We propose an experimentally feasible scheme to implement the optimal asymmetric economical 1→2 phase-covariant quantum cloning in two dimensions based on the cavity QED technique. The protocol is very simple and only two atoms are required. Our scheme is insensitive to the cavity field states and cavity decay. During the processes, the cavity is only virtually excited and it thus greatly prolongs the efficient decoherent time. Therefore, it may be realized in experiment.  相似文献   

    

WANG Ya-Hong SONG He-Shan YU Chang-Shui 《理论物理通讯》2008,49(5):1199-1202

A scheme is proposed for the controlled teleportation of an arbitrary two-atom state via special W-type entangled states and QED cavity. The scheme does not involve the direct joint Bell-state-measurement （BSM）. We show that the quantum information is split into two parts~ thus the original atomic state cannot be perfectly restored by the receiver without the other agent＇s collaboration and classical communication. In addition, the physical realization of this scheme is not difficult.  相似文献   

    

SONG Wei 《理论物理通讯》2008,49(5):1221-1224

We propose a scheme for concentrating entanglement of partially entangled states for atoms trapped in the distant cavities. The scheme is based on adiabatic passage and photonic interference. It is robust against a number of practical noises such as the violation of the Lamb-Dicke condition, spontaneous emission and detection inefficiency.  相似文献   

    

CHEN Ai-Xi HUANG Ke-Lin DENG Li 《理论物理通讯》2007,48(4):641-644

In this paper, a scheme is proposed for realization of two-qubit controlled-not gates and teleportation of an entangled state of atom-cavity. In this scheme, applying hyperfine levels of atom, we consider A-type three-level atom interacting resonantly or nonresonantly with cavity field that is prepared in σ- polarized. We consider the experimental feasibility of this scheme and compare our results with other schemes.  相似文献