Gate fidelity and coherence of an electron spin in an Si/SiGe quantum dot with micromagnet

Gate fidelity and coherence of an electron spin in an Si/SiGe quantum dot with micromagnet

Kawakami, E. (TU Delft QCD/Vandersypen Lab; TU Delft QN/Quantum Transport; TU Delft QuTech; Kavli institute of nanoscience Delft)
Jullien, T.M.J. (TU Delft QN/Quantum Transport; TU Delft QuTech; Kavli institute of nanoscience Delft)
Scarlino, P. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech; Kavli institute of nanoscience Delft)
Ward, Daniel R. (University of Wisconsin-Madison)
Savage, Donald E. (University of Wisconsin-Madison)
Lagally, Max G. (University of Wisconsin-Madison)
Dobrovitski, V.V. (Iowa State University)
Friesen, Mark (University of Wisconsin-Madison)
Coppersmith, Susan N. (University of Wisconsin-Madison)
Eriksson, M.A. (University of Wisconsin-Madison)
Vandersypen, L.M.K. (TU Delft QCD/Vandersypen Lab; TU Delft QN/Vandersypen Lab; TU Delft QuTech; Kavli institute of nanoscience Delft; Components Research)

QuTech

2016-10-18

The gate fidelity and the coherence time of a quantum bit (qubit) are important benchmarks for quantum computation. We construct a qubit using a single electron spin in an Si/SiGe quantum dot and control it electrically via an artificial spin-orbit field from a micromagnet. We measure an average single-qubit gate fidelity of ∼99% using randomized benchmarking, which is consistent with dephasing from the slowly evolving nuclear spins in the substrate. The coherence time measured using dynamical decoupling extends up to ∼400 μs for 128 decoupling pulses, with no sign of saturation. We find evidence that the coherence time is limited by noise in the 10-kHz to 1-MHz range, possibly because charge noise affects the spin via the micromagnet gradient. This work shows that an electron spin in an Si/SiGe quantum dot is a good candidate for quantum information processing as well as for a quantum memory, even without isotopic purification.

Dynamical decoupling
Electron spin
Qubit
Randomized benchmarking
Si/SiGe quantum dot

http://resolver.tudelft.nl/uuid:1746c5e8-c757-42b7-a127-e383272afcc9

https://doi.org/10.1073/pnas.1603251113

2017-04-18

0027-8424

Proceedings of the National Academy of Sciences of the United States of America, 113 (42), 11738-11743

Institutional Repository

journal article

© 2016 E. Kawakami, T.M.J. Jullien, P. Scarlino, Daniel R. Ward, Donald E. Savage, Max G. Lagally, V.V. Dobrovitski, Mark Friesen, Susan N. Coppersmith, M.A. Eriksson, L.M.K. Vandersypen