TY - JOUR
T1 - A quantum-dot spin qubit with coherence limited by charge noise and fidelity higher than 99.9%
AU - Yoneda, Jun
AU - Takeda, Kenta
AU - Otsuka, Tomohiro
AU - Nakajima, Takashi
AU - Delbecq, Matthieu R.
AU - Allison, Giles
AU - Honda, Takumu
AU - Kodera, Tetsuo
AU - Oda, Shunri
AU - Hoshi, Yusuke
AU - Usami, Noritaka
AU - Itoh, Kohei M
AU - Tarucha, Seigo
PY - 2017/12/18
Y1 - 2017/12/18
N2 - The isolation of qubits from noise sources, such as surrounding nuclear spins and spin–electric susceptibility1–4, has enabled extensions of quantum coherence times in recent pivotal advances towards the concrete implementation of spin-based quantum computation. In fact, the possibility of achieving enhanced quantum coherence has been substantially doubted for nanostructures due to the characteristic high degree of background charge fluctuations5–7. Still, a sizeable spin–electric coupling will be needed in realistic multiple-qubit systems to address single-spin and spin–spin manipulations8–10. Here, we realize a single-electron spin qubit with an isotopically enriched phase coherence time (20 μs)11,12 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 noise—rather than conventional magnetic noise—as highlighted by a 1/f spectrum extended over seven decades of frequency. The qubit exhibits superior performance with single-qubit gate fidelities exceeding 99.9% on average, offering a promising route to large-scale spin-qubit systems with fault-tolerant controllability.
AB - The isolation of qubits from noise sources, such as surrounding nuclear spins and spin–electric susceptibility1–4, has enabled extensions of quantum coherence times in recent pivotal advances towards the concrete implementation of spin-based quantum computation. In fact, the possibility of achieving enhanced quantum coherence has been substantially doubted for nanostructures due to the characteristic high degree of background charge fluctuations5–7. Still, a sizeable spin–electric coupling will be needed in realistic multiple-qubit systems to address single-spin and spin–spin manipulations8–10. Here, we realize a single-electron spin qubit with an isotopically enriched phase coherence time (20 μs)11,12 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 noise—rather than conventional magnetic noise—as highlighted by a 1/f spectrum extended over seven decades of frequency. The qubit exhibits superior performance with single-qubit gate fidelities exceeding 99.9% on average, offering a promising route to large-scale spin-qubit systems with fault-tolerant controllability.
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U2 - 10.1038/s41565-017-0014-x
DO - 10.1038/s41565-017-0014-x
M3 - Article
C2 - 29255292
AN - SCOPUS:85038362915
SP - 1
EP - 5
JO - Nature Nanotechnology
JF - Nature Nanotechnology
SN - 1748-3387
ER -