The Hybrid System Composed Of An On-chip Microwave Resonator And Semiconductor Quantum Dots

Circuit quantum electrodynamics promises an effective approach in scalable quantum computing processing and quantum non-demolition readout in solid-state systems.With the development of hybrid semiconductor-superconducting devices,the coherence time of semiconductor qubits and the quality of superconducting microwave resonators have been improved.Also,with the application of high-impedance resonators,the coupling strength between quantum dots and the superconducting microwave resonator has been greatly increased,leading to the achievement of the strong coupling limit in the charge-photon interaction and the spin-photon interaction.In this thesis,we focus on the hybrid semiconductor-superconducting circuit quantum electrodynamics system,and explore the qubit state readout via the resonator and the scaling-up in semiconductor systems.The main context includes:1.Brief introduction of quantum computing and the significance of studying hybrid semiconductor-superconducting circuit quantum electrodynamics systems.The backgrounds and the latest progress are discussed.2.Systematic introduction of the fundamental knowledge about semiconductor quantum dots,superconducting microwave resonators,circuit quantum electrodynamics,and hybrid semiconductor-superconducting circuit quantum electrodynamics system.The coupling mechanism between quantum dots and resonators are discussed.The main measuring method in the hybrid semiconductor-superconducting circuit quantum electrodynamics system and the method to extract the system parameters are introduced.3.Based on the time-averaged dispersive readout,the coherence times of Rabi oscillation and Ramsey fringe are determined.4.Demonstration of the hybrid device composed of a superconducting quantum interference device(SQUID)array resonator and two GaAs double quantum dots.The phenomena of strong coupling and the coherent coupling between two nonlocal qubits are observed.Meanwhile,from the two-qubit correlated spectrum,the coupling between nonlocal semiconductor qubits is systematically studied.This method can intuitively characterize the coupling of two-microwave-photon-coupled qubits,and the system parameters can be obtained from the geometric features in the two-qubit spectra.5.Investigation of the scalable hybrid semiconductor-superconducting circuit quantum electrodynamics architecture.By measuring the collective microwave response,we characterize the device composed of five working double quantum dots and a high-impedance NbTiN resonator,demonstrating the high tunability and the high cooperativity of our device.The main creative points in this thesis contain:1.Achievement of the strong coupling between two semiconductor qubits and the superconducting quantum interference device array resonator.2.First experiment of the time-averaged dispersive readout,which is employed to study the quantum dynamics processing of a charge qubit in our device.3.Exploring the coupling between nonlocal photon-mediated qubits from the twoqubit correlated spectrum measurement.4.First experiment of integrating 5 charge qubits into a resonator.