多量子比特利用量子数据总线耦合

采用高阻抗谐振腔作为量子总线实现了五到六个量子比特的集成与耦合。制备了中心导体长度~700 um，宽度~0.3 um的高阻抗铌钛氮微带微波谐振腔，并在中心导体的两端集成了六个双量子点。通过谐振腔，我们对双量子点（DQD）进行了表征，测量结果标明有五个DQD可以正常工作。为了表征多个比特与谐振腔之间的耦合，我们依次将比特的频率调至谐振腔的谐振频率附近，并观察杂化系统的微波响应。从实验结果上，我们观测到比特们对谐振腔的作用由弱到强，由线性到非线性，表明了我们通过谐振腔完成了多个比特的集成。

A high-impedance resonator cavity was employed as a quantum bus to realize the integration and coupling of five to six qubits. We fabricated a high-impedance niobium titanium nitride (NbTiN) microstrip microwave resonator with a central conductor of ~700 μm in length and ~0.3 μm in width, and integrated six double quantum dots at both ends of the central conductor. Using this resonator, we characterized the double quantum dots (DQDs); the measurement results indicated that five of the DQDs operated normally. To characterize the coupling between multiple qubits and the resonator, we sequentially tuned the frequency of each qubit to near the resonant frequency of the resonator and observed the microwave response of the hybrid system. From the experimental results, we observed that the interaction between the qubits and the resonator transitions from weak to strong, and from linear to nonlinear, which demonstrates that we have accomplished the integration of multiple qubits via the resonator.