Practical Quantum computing hinges on the ability to control large numbers of qubits with high fidelity. Quantum dots define a promising platform due to their compatibility with semiconductor manufacturing. Moreover, high-fidelity operations above 99.9% have been realized with individual qubits, though their performance has been limited to 98.67% when driving two qubits simultaneously. Here we present single-qubit randomized benchmarking in a two-dimensional array of spin qubits, finding native gate fidelities as high as 99.992(1)%. Furthermore, we benchmark single qubit gate performance while simultaneously driving two and four qubits, utilizing a novel benchmarking technique called N-copy randomized benchmarking, designed for simple experimental implementation and accurate simultaneous gate fidelity estimation. We find two- and four-copy randomized benchmarking fidelities of 99.905(8)% and 99.34(4)% respectively, and that next-nearest neighbor pairs are highly robust to cross-talk errors. These characterizations of single-qubit gate quality are crucial for scaling up quantum information technology.

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Nature Communications
Quantum Software Consortium
Centrum Wiskunde & Informatica, Amsterdam (CWI), The Netherlands

Lawrie, W. I. L., Rimbach-Russ, M., van Riggelen, F., Hendrickx, N. W., de Snoo, S. L., Sammak, A., … Veldhorst, M. (M.). (2023). Simultaneous single-qubit driving of semiconductor spin qubits at the fault-tolerant threshold. Nature Communications, 14. doi:10.1038/s41467-023-39334-3