Realization Of Two-qubit Rabi Model And Quantum Gate In Circuit QED System

The quantum Rabi model is a simple model in quantum optics,and describes the fundamentals of light-matter interaction.When the interaction strength is small,it reduces to the Jaynes–Cummings model by applying a rotating wave approximation.With the improvement of experimental techniques,strong coupling and even ultrastrong-coupling systems have been realized on various experimental platforms,such as superconducting circuits,quantum optical systems,trapped ions,cold atoms and so on.However,even if quantum technology has greatly improved today,it is not easy to achieve ultrastrongcoupling and deep strong coupling systems.Therefore,the realization of ultrastrongcoupling,even deep strong coupling by the use of quantum simulation which has important research value for studying the dynamic behavior of ultrastrong-coupling and deep strong coupling regions.Based on research works,we studied how to realize the multi-qubit quantum Rabi model.The research shows that we can achieve higher fidelity multi-qubit Rabi model by choosing the parameters reasonably.In particular,we showed the application of multi-qubit Rabi model in quantum computation.We can use the effective Hamiltonian of the system to realize non-trivial quantum gate and multi-qubit entanglement.Finally,we studied the properties of the non-trivial quantum gate we constructed and their fidelity.In this dissertation,introduction gives the research background of this dissertation.We introduced the development of quantum entanglement theory,and some concepts,such as quantum gate and Rabi model,as well as superconducting circuit systems.In chapter two,firstly we reviewed some systems which can realize the Rabi model,and how to generate cat state through effective Hamiltonian.The third chapter is the focus of our research.We introduced the driving term to implement a multi-qubit Rabi model with reasonable parameters,and studied the application of effective Hamiltonian in constructing non-trivial quantum gate and multi-qubit quantum entangle states.It shows that we can implement higher fidelity quantum logic gate and quantum logic gate which is equivalent to CNOT gates under certain parameters.Finally,we gave the conclusion of the dissertation.