Generating The Maximally Entangled Channel State And Quantum Cloning In Cavity QED

Compared with classical information, quantum information has many characteristics, such as quantum entanglement, quantum no-cloning and so on. Quantum entanglement has wide application in quantum comunication, such as dense coding, quantum teleportation and so on. The theorem of quantum no-cloning guarantees the quantum key allocation's security, so that information can be transported safely. Therefore, the paper based on cavity QED gives the related research and exploration, and proposes the concrete schemes to generate the entangled state and quantum cloning, mainly including the following several aspects:1. Our paper present a simple scheme to teleporte an unknown atomic state using an atomic Bell state in cavity QED system. With the help of an auxiliary atom, the scheme can make single-atom detection instead Bell-state measurement,and its successful probability can reach 1.2. The paper first studies the entanglement character of G-type maximally entangled state (GMES) and 2N-qubit maximally entangled channel state; and then prepares them in cavity QED system, respectively.3. In the cavity QED system, we proposed the unitary transformation. In the transformation, by choosing different parameter value, the scheme can realize universal cloning and phase covariant cloning, respectively.4. We propose an experimentally feasible scheme to implement the economical 1→M phase-covariant telecloning based on cavity QED. By the resonant interaction of the atoms with cavity field and the different coupling strength between atoms and cavity field, the scheme can generate quantum entanglement channel in one step. What's more, the operation time and steps do not increase with the increase of atoms.