Quantum Communication Schemes Via Cavity QED

Quantum information theory is an inter-discipline of quantum mechanics and information theory, which is competent in some of impossible task within the conventional information science. Quantum communication is a way of effective information transmission using quantum state as information unit. It is an important and early researched branch of quantum information, including quantum teleportation, quantum dense coding, quantum secret sharing, etc.Cavity QED is one of the most promising candidates serving as hardware of quantum information, atoms trapped in the cavity can be ideal memory for quantum information. One of the distinct advantages of quantum information processing in the context of cavity QED is that the manipulation is very simple, photon is ideal for flying qubit and the system is easy to scalable. Up to now, quantum information processing in cavity QED is mainly in the theoretical stage, the only experimental demonstration is the generation of entangled state. Thus it is of extremely importance to find experimental feasible scheme for quantum information processing in the context of cavity QED. In this paper, quantum communication in cavity QED is studied, some mainly results including1. We present a feasible scheme for entangled state teleportation, which is free of joint measurement. Bell state measurement is indispensable in many tasks in quantum information processing, but it is very difficult for experimental demonstration. Our scheme is free of directly joint measurement and the effective cavity decay time is also greatly prolonged by virtual excitation.2. We present a probabilistic quantum dense coding scheme in the context of cavity QED. But, quantum dense coding scheme using atomic qubit serving as both stationary and flying qubit is obviously difficult for experimental demonstration. Atomic state is not ideal for flying qubit and Bell state measurement is also a problem-maker. Thus later in this paper we present a secure scheme for quantum dense coding based on multipartite, which also holds two other distinct advantages:...