Print Email Facebook Twitter Fast universal quantum gate above the fault-tolerance threshold in silicon Title Fast universal quantum gate above the fault-tolerance threshold in silicon Author Noiri, A. Takeda, K. Nakajima, T. Kobayashi, T. Sammak, A. Scappucci, G. Tarucha, S. Publication year 2022 Abstract Fault-tolerant quantum computers that can solve hard problems rely on quantum error correction1. One of the most promising error correction codes is the surface code, which requires universal gate fidelities exceeding an error correction threshold of 99%. Among the many qubit platforms, only superconducting circuits, trapped ions and nitrogen-vacancy centres in diamond have delivered this requirement. Electron spin qubits in silicon are particularly promising for a large-scale quantum computer owing to their nanofabrication capability, but the two-qubit gate fidelity has been limited to 98% owing to the slow operation. Here we demonstrate a two-qubit gate fidelity of 99.5%, along with single-qubit gate fidelities of 99.8%, in silicon spin qubits by fast electrical control using a micromagnet-induced gradient field and a tunable two-qubit coupling. We identify the qubit rotation speed and coupling strength where we robustly achieve high-fidelity gates. We realize Deutsch–Jozsa and Grover search algorithms with high success rates using our universal gate set. Our results demonstrate universal gate fidelity beyond the fault-tolerance threshold and may enable scalable silicon quantum computers. Subject High Tech Systems & MaterialsIndustrial Innovation To reference this document use: http://resolver.tudelft.nl/uuid:737df4cc-469e-4b11-9198-6a9318d2a8a0 DOI https://doi.org/10.1038/s41586-021-04182-y TNO identifier 963098 Publisher Springer Nature, Heidelberg, Germany Source Nature, 338-342 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.