A quantum-dot spin qubit with coherence limited by charge noise and fidelity higher than 99.9%
| Autor: | Shunri Oda, Seigo Tarucha, Kohei M. Itoh, Yusuke Hoshi, Giles Allison, Kenta Takeda, Jun Yoneda, Tetsuo Kodera, Noritaka Usami, Takumu Honda, M. R. Delbecq, Tomohiro Otsuka, Takashi Nakajima |
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| Rok vydání: | 2017 |
| Předmět: |
Physics
Spins Dephasing Biomedical Engineering Bioengineering 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Atomic and Molecular Physics and Optics Controllability Microsecond Quantum dot Quantum mechanics Qubit 0103 physical sciences Condensed Matter::Strongly Correlated Electrons General Materials Science Electrical and Electronic Engineering 010306 general physics 0210 nano-technology Quantum computer Coherence (physics) |
| Zdroj: | Nature Nanotechnology. 13:102-106 |
| ISSN: | 1748-3395 1748-3387 |
| DOI: | 10.1038/s41565-017-0014-x |
| Popis: | Recent advances towards spin-based quantum computation have been primarily fuelled by elaborate isolation from noise sources, such as surrounding nuclear spins and spin-electric susceptibility, to extend spin coherence. In the meanwhile, addressable single-spin and spin-spin manipulations in multiple-qubit systems will necessitate sizable spin-electric coupling. Given background charge fluctuation in nanostructures, however, its compatibility with enhanced coherence should be crucially questioned. Here we realise a single-electron spin qubit with isotopically-enriched phase coherence time (20 microseconds) and fast electrical control speed (up to 30 MHz) mediated by extrinsic spin-electric coupling. Using rapid spin rotations, we reveal that the free-evolution dephasing is caused by charge (instead of conventional magnetic) noise featured by a 1/f spectrum over seven decades of frequency. The qubit nevertheless exhibits superior performance with single-qubit gate fidelities exceeding 99.9% on average. Our work strongly suggests that designing artificial spin-electric coupling with account taken of charge noise is a promising route to large-scale spin-qubit systems having fault-tolerant controllability. |
| Databáze: | OpenAIRE |
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