Precision tomography of a three-qubit donor quantum processor in silicon
Research output: Contribution to journal › Journal article › Research › peer-review
Nuclear spins were among the first physical platforms to be considered for quantum information processing1,2, because of their exceptional quantum coherence3 and atomic-scale footprint. However, their full potential for quantum computing has not yet been realized, owing to the lack of methods with which to link nuclear qubits within a scalable device combined with multi-qubit operations with sufficient fidelity to sustain fault-tolerant quantum computation. Here we demonstrate universal quantum logic operations using a pair of ion-implanted 31P donor nuclei in a silicon nanoelectronic device. A nuclear two-qubit controlled-Z gate is obtained by imparting a geometric phase to a shared electron spin4, and used to prepare entangled Bell states with fidelities up to 94.2(2.7)%. The quantum operations are precisely characterized using gate set tomography (GST)5, yielding one-qubit average gate fidelities up to 99.95(2)%, two-qubit average gate fidelity of 99.37(11)% and two-qubit preparation/measurement fidelities of 98.95(4)%. These three metrics indicate that nuclear spins in silicon are approaching the performance demanded in fault-tolerant quantum processors6. We then demonstrate entanglement between the two nuclei and the shared electron by producing a Greenberger–Horne–Zeilinger three-qubit state with 92.5(1.0)% fidelity. Because electron spin qubits in semiconductors can be further coupled to other electrons7–9 or physically shuttled across different locations10,11, these results establish a viable route for scalable quantum information processing using donor nuclear and electron spins.
Original language | English |
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Journal | Nature |
Volume | 601 |
Issue number | 7893 |
Pages (from-to) | 348-353 |
Number of pages | 6 |
ISSN | 0028-0836 |
DOIs | |
Publication status | Published - 20 Jan 2022 |
Bibliographical note
Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer Nature Limited.
Links
- https://arxiv.org/pdf/2106.03082.pdf
Submitted manuscript
ID: 307522870