title: Isotopically enhanced triple-quantum-dot qubit.
abstract: Like modern microprocessors today, future processors of quantum information may be implemented using all-electrical control of silicon-based devices. A semiconductor spin qubit may be controlled without the use of magnetic fields by using three electrons in three tunnel-coupled quantum dots. Triple dots have previously been implemented in GaAs, but this material suffers from intrinsic nuclear magnetic noise. Reduction of this noise is possible by fabricating devices using isotopically purified silicon. We demonstrate universal coherent control of a triple-quantum-dot qubit implemented in an isotopically enhanced Si/SiGe heterostructure. Composite pulses are used to implement spin-echo type sequences, and differential charge sensing enables single-shot state readout. These experiments demonstrate sufficient control with sufficiently low noise to enable the long pulse sequences required for exchange-only two-qubit logic and randomized benchmarking.
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Eng
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Thaddeus D
authors.initials: TD
authors.lastname: Ladd
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Smith
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Borselli
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Andrey A
authors.initials: AA
authors.lastname: Kiselev
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Bryan H
authors.initials: BH
authors.lastname: Fong
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Holabird
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Hazard
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Biqin
authors.initials: B
authors.lastname: Huang
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Deelman
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Ivan
authors.initials: I
authors.lastname: Milosavljevic
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Adele E
authors.initials: AE
authors.lastname: Schmitz
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Richard S
authors.initials: RS
authors.lastname: Ross
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Mark F
authors.initials: MF
authors.lastname: Gyure
authors.affiliation: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Hunter
keywords: Qubits; isotopically enhanced semiconductors; quantum control; quantum dots; quantum information; semiconductor heterostructures