1. Low-loss interconnects for modular superconducting quantum processors
- Author
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Niu, Jingjing, Zhang, Libo, Liu, Yang, Qiu, Jiawei, Huang, Wenhui, Huang, Jiaxiang, Jia, Hao, Liu, Jiawei, Tao, Ziyu, Wei, Weiwei, Zhou, Yuxuan, Zou, Wanjing, Chen, Yuanzhen, Deng, Xiaowei, Deng, Xiuhao, Hu, Changkang, Hu, Ling, Li, Jian, Tan, Dian, Xu, Yuan, Yan, Fei, Yan, Tongxing, Liu, Song, Zhong, Youpeng, Cleland, Andrew N., and Yu, Dapeng
- Subjects
Quantum Physics - Abstract
Scaling is now a key challenge in superconducting quantum computing. One solution is to build modular systems in which smaller-scale quantum modules are individually constructed and calibrated, and then assembled into a larger architecture. This, however, requires the development of suitable interconnects. Here, we report low-loss interconnects based on pure aluminium coaxial cables and on-chip impedance transformers featuring quality factors up to $8.1 \times 10^5$, which is comparable to the performance of our transmon qubits fabricated on single-crystal sapphire substrate. We use these interconnects to link five quantum modules with inter-module quantum state transfer and Bell state fidelities up to 99\%. To benchmark the overall performance of the processor, we create maximally-entangled, multi-qubit Greenberger-Horne-Zeilinger (GHZ) states. The generated inter-module four-qubit GHZ state exhibits 92.0\% fidelity. We also entangle up to 12 qubits in a GHZ state with $55.8 \pm 1.8\%$ fidelity, which is above the genuine multipartite entanglement threshold of 1/2. These results represent a viable modular approach for large-scale superconducting quantum processors.
- Published
- 2023
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