Theoretical Researches And Implementation On Quantum Teleportation

Information science plays a key role in improving the life of people and the progress of civilization. We experience an ever-increasing need for technology that allows us to share information in a secure, efficient and reliable way. Theoretical research in the information science has identified that quantum methods are better than classical counterparts. Quantum information science is a new discipline, which is a combination of quantum mechanics and information science. Quantum computation and quantum communication are two important branches of it. At present, quantum communication mainly includes preparation of quantum state, quantum information, quantum dense coding, quantum key distribution, quantum remote state preparation, and so on. Quantum teleportation is one of the most strikingly developing fields in the quantum communication. Since Bennett et al. has proposed a scheme to teleport an unknown quantum state via classical and quantum EPR channel in 1993, much attention has been paid to quantum teleportation. Quantum teleportation has been extended from discrete- variable systems to continuous-variable systems and also from single particle to multi particles. On the other hand, experimental demonstration of quantum teleportation has been realized with photon polarized states, optical coherent states, and nuclear magnetic resonance recently.In the paper, we make a systematic theoretical study about quantum teleportation. Firstly, we introduce a basic theory of quantum communication, like quantum bit, quantum entanglement and quantum logical gate. And then, ve discuss the optimal probabilistic teleportation of an unknown S-level particle state via the quantum channel that is prepared by L pairs non-maximally entangled states of two-level particles. We propose a simple scheme for the teleportation of multi-particles entangled W state from a sender to a receiver via the control of M agents. If one agent does not cooperate, the receiver cannot full recover the state of sender. At the same time, we propose a scheme for conditional teleportation of a two-mode entanglement of zero- and one-photon states without the Bell-state measurement.