Low-loss interconnects for modular superconducting quantum processors
- Southern University of Science and Technology (SUSTech), Shenzhen (China); International Quantum Academy, Shenzhen (China); Hefei National Laboratory, Shenzhen (China)
- Southern University of Science and Technology (SUSTech), Shenzhen (China); International Quantum Academy, Shenzhen (China)
- Univ. of Chicago, IL (United States); Argonne National Laboratory (ANL), Argonne, IL (United States). Center for Molecular Engineering
Low-loss superconducting aluminium cables and on-chip impedance transformers can be used to link qubit modules and create superconducting quantum computing networks with high-fidelity intermodule state transfer. 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 of up to 8.1 x 105, which is comparable with the performance of our transmon qubits fabricated on a single-crystal sapphire substrate. We use these interconnects to link five quantum modules with intermodule quantum state transfer and Bell state fidelities of up to 99%. To benchmark the overall performance of the processor, we create maximally entangled, multiqubit Greenberger-Horne-Zeilinger states. The generated intermodule four-qubit Greenberger-Horne-Zeilinger state exhibits 92.0% fidelity. We also entangle up to 12 qubits in a Greenberger-Horne-Zeilinger state with 55.8 ± 1.8% fidelity, which is above the genuine multipartite entanglement threshold of 1/2.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE; National Natural Science Foundation of China (NSFC); Key Area Research and Development Program of Guangdong Province; Guangdong Provincial Key Laboratory; Science, Technology and Innovation Commission of Shenzhen Municipality; Shenzhen-Hong Kong Cooperation Zone for Technology and Innovation; National Science Foundation of Beijing
- Grant/Contract Number:
- AC02-06CH11357; U1801661; 12174178; 2019B121203002; KYTDPT20181011104202253; KQTD20210811090049034; HZQB-KCZYB-2020050; Z190012
- OSTI ID:
- 1989368
- Journal Information:
- Nature Electronics, Vol. 6, Issue 3; ISSN 2520-1131
- Publisher:
- Springer NatureCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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