The Generation Of Six-cluster States In Ion-Trap And Preparing Two-qubit State Of General Formation Remotely Via Cavity-QED

Quantum information is based on the basic principle of quantum mechanics. Quantum entanglement is the most special characteristic of quantum mechanics, and it is also the main reason that yields the essential difference between quantum information and classic information.Quantum entanglement plays a very important role in quantum information . Using quantum superposition and coherence, one can realize the parallel computing of quantum computer, so the efficiency of quantum computer has greatly enhanced. Furthermore, quantum entanglement can be used as a quantum channel to realize most quantum techniques, such as quantum teleportation and quantum secure direct communication.Among the schemes of physical realization of quantum computer, most people are optimistic about the ion trap programme. So a lot of research about ion trap has been done. Multi-particle entanglement is another research focus in recent years. Briegel have introduced another class of multi-qubit entangled states—cluster states and then it has been showed that the cluster states constitute a universal resource for so-called one-way quantum computation. People are more interested in researching cluster states now. We propose a scheme for the generation of six-cluster states in ion-trap systems, which is based on resonant sideband excitation. In addition, we present the fidelity of our scheme. In our scheme, we have use eight resonant sideband excitation, the fidelity of which is 0.93, so the fidelity of our scheme is 0.56. The scheme is realizable with presently available experimental techniques. We expect that the fidelity of each sideband excitation can be enhanced, so can our scheme.The earliest ideas of quantum superdense coding and quantum teleportation are both brought forward by Bennett. They used EPR pairs as quantum channel. In fact, the decoherence may arise because of the interaction between quantum channel and the environment. So the entangled states used as quantum channel are always not maximal entangled states. Therefore, we propose a scheme for preparing two-qubit states of general formation remotely via cavity Quantum Electro-Dynamic(QED) technologies. In our scheme, the maximal entangled states used as channel are generated via cavity-QED. The interaction between atoms and a single-mode cavity assistance of a strong classical driving field. It is insensitive to the cavity decay and environmental field. In addition, our scheme is realizable with presently available experimental techniques.