| Circuit quantum electrodynamics(QED)systems can realize the coupling between qubits and superconducting microwave cavities,which is an ideal platform for studying light-matter interactions.In recent years,the circuit QED system has attracted widespread attention due to its application in realizing long-range coherent coupling and quantum system state readout,and its feasibility of studying the various phenomena in quantum optics.Taking advantage of high tunability and considerable electric dipole moment,semiconductor quantum dot(QD),as an "artificial atom",is an ideal component of circuit QED architecture.Benefiting from the advances in device structure and fabrication processes,the strong coupling between semiconductor qubits and cavities as well as the cavity-mediated long-range coherent coupling between two semiconductor qubits have been realized,which lays the foundation for the applications of circuit QED in the scaling-up to large qubit arrays and quantum information processing.Moreover,semiconductor QD embraces rich underlying physics,such as spin degree of freedom and electron-phonon interactions,which is beneficial for investigating intriguing phenomena.This paper focuses on the GaAs semiconductor QD-superconducting cavity systems,and investigates the electron-photon interaction and the dynamics of periodically driven systems.The main contents of the full text include the following points:1.Introduction of the semiconductor QD-based circuit QED systems.The important role of the high-impedance cavities and the applications of periodic driving are discussed;2.Basic theories and experimental methods are introduced,including the basic knowledge of the coupling systems and high-impedance cavities,the structure of the hybrid samples,the measurement circuit and methods of sample characterization,and the basic theory for periodic driving.3.The SQUID array cavity is used to characterize the GaAs triple quantum dots.The quantum cellular automata,photon-assisted quadruple point,and spin blockade in the charge stability diagram are investigated;4.The cavity photon generation is studied in a periodically driven hybrid system consisting of a GaAs double quantum dot(DQD)and a NbTiN cavity.By applying a periodic driving to the DQD,the cavity photon generation and the observation of the cavity transmission amplitude gain are achieved with the assistance of electron-phonon interactions.Furthermore,the influence of different driving and DQD parameters on the cavity gain is studied in detail;5.The dynamic behavior of the periodically driven hybrid system with large coupling strength is investigated.The coupling strength between the GaAs DQD and the NbTiN cavity is further improved,and the Floquet state behavior of a single-DQDcavity and a two-DQD-cavity system with periodic drivings are studied.To describe such systems and reveal the underlying physics,a new response theory has been developed.And within the theoretical framework,the observed phenomena are well reproduced and explained.The originality of this thesis can be summarized as follows:1.By improving the detective sensitivity with a high-impedance cavity,the quantum cell automata and photon-assisted quadruple point are experimentally investigated via a cavity for the first time.And it is revealed with the theory that these phenomena appear under special energy relationships.This work lays the groundwork for the study of multi-QD-cavity systems and many-body interactions;2.By utilizing a high-impedance cavity to improve the coupling strength between the planar DQD and the cavity,the cavity photon generation and cavity amplitude gain are realized by applying a periodic driving to a planar DQD-cavity system for the first time.Moreover,the tunable cavity amplitude gain is demonstrated by adjusting the cavity photon emission process through the system parameters.This scheme can be applied to other planar QD-cavity systems.Moreover,the results make a step towards the QD-based engineering of the cavity field as well as controllable on-chip microwave sources and amplifiers;3.The system consisting of multiple DQDs and a cavity with large coupling strength under periodic drivings is systematically studied in the experiment.A new theory is proposed and utilized to interpret the experimental data,which reveals that the cavity transmission signal reflects the change of Floquet state occupation.These findings provide a new perspective for understanding driven coupled systems,deepen the understanding of the Floquet states of the coupled system,and may motivate future applications in scalable hybrid quantum systems. |
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