Trapped Ion And Cavity Qed-based Quantum Entanglement And Quantum Computing

Quantum entanglement is the most fundamental resource of quantum information science. In fact, quantum information science does not exist without quantum entanglement. Therefore, quantum entanglement plays a very key role in quantum information science. Quantum computation is not only the most challenging area of quantum information science, but also the original motivation and cause which have resulted in a lot of investigation on quantum information science. Since the trapped ions and the cavity QED are two very important physical systems by which the theories of quantum entanglement and quantum computation can be demonstrated and tested, they play both very important roles in studying quantum entanglement and quantum computation. The main contents are as follows:1. Based on the physical system of tapped ions,utilizing the interaction of laser with trapped multi-level ions, a high-dimensional quantum computation (i.e., ququadrit quantum computation) scheme is presented. Using the interaction of dichromatic field with tapped ions, we propose a scheme for realizing step by step quantum CNOT gate with a specific laser pulse sequence.2. Based on the physical system of cavity QED and using the multi-photon interaction between the cavity mode and atoms, we propose a novel scheme for implementation of non-conventional geometric quantum computation originated from high-dimensional squeezed operators, which can be easily generalized to the physical system of trapped ions. Secondly, utilizing the resonant interaction of laser with atoms in the cavity, we present another scheme named for strong-driven geometric quantum logic gate via cavity QED, in which the influence of the cavity decay on the quantum logic gate has been in detail considered. Finally, we propose an interesting scheme for implementation of approximate and high-fidelity quantum Toffoli gate via single photon resonant interaction of the cavity mode with the atoms in the cavity.