RT Journal Article
SR Electronic
T1 A fault-tolerant addressable spin qubit in a natural silicon quantum dot
JF Science Advances
JO Sci Adv
FD American Association for the Advancement of Science
SP e1600694
DO 10.1126/sciadv.1600694
VO 2
IS 8
A1 Takeda, Kenta
A1 Kamioka, Jun
A1 Otsuka, Tomohiro
A1 Yoneda, Jun
A1 Nakajima, Takashi
A1 Delbecq, Matthieu R.
A1 Amaha, Shinichi
A1 Allison, Giles
A1 Kodera, Tetsuo
A1 Oda, Shunri
A1 Tarucha, Seigo
YR 2016
UL http://advances.sciencemag.org/content/2/8/e1600694.abstract
AB Fault-tolerant quantum computing requires high-fidelity qubits. This has been achieved in various solid-state systems, including isotopically purified silicon, but is yet to be accomplished in industry-standard natural (unpurified) silicon, mainly as a result of the dephasing caused by residual nuclear spins. This high fidelity can be achieved by speeding up the qubit operation and/or prolonging the dephasing time, that is, increasing the Rabi oscillation quality factor Q (the Rabi oscillation decay time divided by the π rotation time). In isotopically purified silicon quantum dots, only the second approach has been used, leaving the qubit operation slow. We apply the first approach to demonstrate an addressable fault-tolerant qubit using a natural silicon double quantum dot with a micromagnet that is optimally designed for fast spin control. This optimized design allows access to Rabi frequencies up to 35 MHz, which is two orders of magnitude greater than that achieved in previous studies. We find the optimum Q = 140 in such high-frequency range at a Rabi frequency of 10 MHz. This leads to a qubit fidelity of 99.6% measured via randomized benchmarking, which is the highest reported for natural silicon qubits and comparable to that obtained in isotopically purified silicon quantum dot–based qubits. This result can inspire contributions to quantum computing from industrial communities.