Research On Features And Application Of Superconducting Qubits In Cavity QED

Recent decades, the development of quantum mechanics and information scienceprovides new opportunity and challenge for information age. New emerging quantumcomputing and quantum information processing arouses high attention all over theworld. Among various physical system which can realize quantum computer, cavityQED and superconducting qubit are the most promising candidates. The groundwork ofrealizing quantum computer is realizing quantum logic gate. Therefore, the realizationof quantum logic gate becomes one of the important concerns for researchers. In thispaper, we mainly research the dynamics behavior of two-site coupled cavity model andthe logic gate realization with superconducting qubits in cavity QED. The mainconclusions are obtained as follows:In chapter1, the basic theories of quantum computation are explained. It isincluding the basic knowledge of quantum logic gate and the study actuality of therealization scheme of quantum computer. The history and progress on the researches ofrealization of quantum computer with superconducting qubits in cavity QED ispresented.In chapter2, the dynamics behavior of coupled cavity model which is doped withtwo-level system is investigated. The exact dynamics solutions in general condition aresolved via Laplace transform. The simple analytical solutions are obtained under severalparticular cases, which describe the various interactions of each part and demonstratethe clear and simple physical picture for the quantum state transition of the system.In chapter3, two schemes are proposed for implementing quantum logic gate withN superconducting quantum interference devices coupled to a cavity QED. We solvethe quantum state evolution equations of superconducting qubits coupled to a cavityfield and driven by the microwave pulse. We propose a method for realizing N-qubitToffoli gate, meanwhile, propose a method for realizing controlled-phase gate. Theexperiment feasibility is analyzed based on the existing experimental parameters.In chapter4, based on N+1three-level qubits coupling to a cavity QED, wepropose two alternative schemes for implementing a controlled-not gate of one controlqubit simultaneously controlling N target qubit. One scheme is based on the adjustmentof all qubits transition frequency, another scheme works mainly via the adjustment ofthe cavity mode frequency and the control qubit transition frequency. Finally, theexperimental possibility of realizing this gate using superconducting charge qubits asexample is analyzed.In chapter5, the summarization and the prospect are presented.