Quantifying the quantum gate fidelity of single-atom spin qubits in silicon by randomized benchmarking

Muhonen, Juha T.; Laucht, Arne; Simmons, Stephanie; Dehollain, Juan Pablo; Kalra, Rachpon; Hudson, Fay E.; Freer, Solomon; Itoh, Kohei M.; Jamieson, David N.; McCallum, Jeffrey C.; Dzurak, A. S.; Morello, Andrea

doi:10.1088/0953-8984/27/15/154205

Cited by 136 publications

(144 citation statements)

References 40 publications

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“…By virtue of 17, (20) and this latter expression is seen to be always positive unless m ≤ −3. Thus the required degeneracy can be achieved only within Si:Bi, specifically addressing the |+, m = −3 → |−, m = −4 transition, which we call allowed transition, and the |+, m = −4 → |−, m = −3 transition, the forbidden one.…”

Section: Discussionmentioning

confidence: 87%

Surface code architecture for donors and dots in silicon with imprecise and nonuniform qubit couplings

et al. 2016

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A scaled quantum computer with donor spins in silicon would benefit from a viable semiconductor framework and a strong inherent decoupling of the qubits from the noisy environment. Coupling neighbouring spins via the natural exchange interaction according to current designs requires gate control structures with extremely small length scales. We present a silicon architecture where bismuth donors with long coherence times are coupled to electrons that can shuttle between adjacent quantum dots, thus relaxing the pitch requirements and allowing space between donors for classical control devices. An adiabatic SWAP operation within each donor/dot pair solves the scalability issues intrinsic to exchange-based two-qubit gates, as it does not rely on sub-nanometer precision in donor placement and is robust against noise in the control fields. We use this SWAP together with well established global microwave Rabi pulses and parallel electron shuttling to construct a surface code that needs minimal, feasible local control.

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Section: Discussionmentioning

confidence: 87%

Surface code architecture for donors and dots in silicon with imprecise and nonuniform qubit couplings

et al. 2016

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“…Closed-loop optimal control [150,424] enabled fine-tuning of gates that were determined manually, allowing them to reach consistent record fidelities within this platform. Control of donor qubits in Si has been achieved and characterized [425]. Control strategies for spins in semiconductors currently trade off conceptually simple single-spin schemes [426,427] with more robust and accessible two-and three spin techniques [428][429][430].…”

Section: State Of the Artmentioning

confidence: 99%

Training Schrödinger’s cat: quantum optimal control

et al. 2015

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Abstract. It is control that turns scientific knowledge into useful technology: in physics and engineering it provides a systematic way for driving a dynamical system from a given initial state into a desired target state with minimized expenditure of energy and resources. As one of the cornerstones for enabling quantum technologies, optimal quantum control keeps evolving and expanding into areas as diverse as quantumenhanced sensing, manipulation of single spins, photons, or atoms, optical spectroscopy, photochemistry, magnetic resonance (spectroscopy as well as medical imaging), quantum information processing and quantum simulation. In this communication, state-of-the-art quantum control techniques are reviewed and put into perspective by a consortium of experts in optimal control theory and applications to spectroscopy, imaging, as well as quantum dynamics of closed and open systems. We address key challenges and sketch a roadmap for future developments. ForewordThe authors of this paper represent the QUAINT consortium, a European Coordination Action on Optimal Control of Quantum Systems, funded by the European Commission Framework Programme 7, Future Emerging Technologies FET-OPEN programme and the Virtual Facility for Quantum Control (VF-QC). This consortium has considerable expertise in optimal control theory and its applications to quantum systems, both in existing areas, such as spectroscopy and imaging, and in emerging quantum technologies, such as quantum information processing, quantum communication, quantum simulation a e-mail: fwm@lusi.uni-sb.de and quantum sensing. The list of challenges for quantum control has been gathered by a broad poll of leading researchers across the communities of general and mathematical control theory, atomic, molecular-, and chemical physics, electron and nuclear magnetic resonance spectroscopy, as well as medical imaging, quantum information, communication and simulation. 144 experts in these fields have provided feedback and specific input on the state of the art, mid-term and long-term goals. Those have been summarized in this document, which can be viewed as a perspectives paper, providing a roadmap for the future development of quantum control. Because such an endeavour can hardly ever be complete (there are many additional areas of quantum control applications, such as spintronics, nano-optomechanical technologies etc.), this roadmap

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“…As illustrated by the color, the unitarity  ( ) u h is minimal in the center of the shaded region and maximal when the data points approach our bound. 6 The current analysis of URB is done under a gate-independent noise approximation. 7 In the interleaved RB lingo, this relation is often expressed as  = ( ) p p p h IRB RB , where  h is the error attached to the interleaved gate.…”

Section: Application: Interleaved Rbmentioning

confidence: 99%

“…preparations, measurements and gate operations) is sufficiently small compared to the length of the computation. A very common experimental practice [1][2][3][4][5][6][7][8][9][10][11][12] for estimating errors on gate operations is randomized benchmarking (RB) of Clifford operations [13,14]. The experimentally measured infidelities under RB experiments have very recently been shown to give a very precise estimate of the average gate fidelity (hereafter simply the fidelity) of an error channel to the identity   ò y y y y y…”

Section: Introductionmentioning

confidence: 99%

Bounding the average gate fidelity of composite channels using the unitarity

2019

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There is currently a significant need for robust and efficient methods for characterizing quantum devices. While there has been significant progress in this direction, there remains a crucial need to precisely determine the strength and type of errors on individual gate operations, in order to assess and improve control as well as reliably bound the total error in a quantum circuit given some partial information about the errors on the components. In this work, we first provide an optimal bound on the total fidelity of a circuit in terms of component fidelities, which can be efficiently experimentally estimated via randomized benchmarking (RB). We then derive a tighter bound that applies under additional information about the coherence of the error, namely, the unitarity, which can also be estimated via a related experimental protocol. This improved bound smoothly interpolates between the worst-case quadratic and best-case linear scaling for composite error channels. As an application we show how our analysis substantially improves the achievable precision on estimates of the infidelities of individual gates under interleaved RB, enabling greater precision for current experimental methods to assess and tune-up control over quantum gate operations.

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Quantifying the quantum gate fidelity of single-atom spin qubits in silicon by randomized benchmarking

Cited by 136 publications

References 40 publications

Surface code architecture for donors and dots in silicon with imprecise and nonuniform qubit couplings

Surface code architecture for donors and dots in silicon with imprecise and nonuniform qubit couplings

Training Schrödinger’s cat: quantum optimal control

Bounding the average gate fidelity of composite channels using the unitarity

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