Precision Tomography of a Three-Qubit Donor Quantum Processor in Silicon
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- Delft Univ. of Technology (Netherlands); UNSW Sydney (Australia)
- Univ. of Copenhagen (Denmark); UNSW Sydney (Australia)
- Univ. of Technology Sydney, Ultimo (Australia); Ain Shams Univ., Cairo (Egypt)
- UNSW Sydney (Australia)
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sandia National Lab. (SNL-CA), Livermore, CA (United States)
- UNSW Sydney (Australia); Univ. of Technology Sydney, Ultimo (Australia)
- Keio Univ., Yokohama (Japan)
- Univ. of Melbourne (Australia)
- Univ. of Technology Sydney, Ultimo (Australia)
Nuclear spins were among the first physical platforms to be considered for quantum information processing, because of their exceptional quantum coherence 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 spin, 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), 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 processors. 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 electrons or physically shuttled across different locations, these results establish a viable route for scalable quantum information processing using donor nuclear and electron spins.
- Research Organization:
- Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories (SNL-CA), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR): Australian Research Council; Australian Department of Industry, Innovation and Science; US Army Research Office
- Grant/Contract Number:
- NA0003525
- OSTI ID:
- 1841674
- Report Number(s):
- SAND--2022-0751J; 703008
- Journal Information:
- Nature (London), Journal Name: Nature (London) Journal Issue: 7893 Vol. 601; ISSN 0028-0836
- Publisher:
- Nature Publishing GroupCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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