Programable two-qubit gates in capacitively coupled flopping-mode spin qubits

Cayao, Jorge; Benito, Mónica; Burkard, Guido

doi:10.1103/physrevb.101.195438

Cited by 15 publications

(6 citation statements)

References 52 publications

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“…At short range, this is effectively a quantum cross-capacitance effect; at larger distances, it has the character of an electrically mediated effective dipole-dipole coupling. It translates to a spin coupling due to exchange, field gradients or spin-orbit (Cayao et al, 2020;Shulman et al, 2012;Stepanenko and Burkard, 2007;Taylor et al, 2005), or due to the hyperfine splitting between electrons and nuclei. The latter effect may benefit the scaling of donor systems, since the electric dipole of a donor impurity may be "stretched" by the action of a gate above the device, enabling electric control of a long-distance dipole-dipole coupling.…”

Section: Capacitive and Electric Dipole-dipole Couplingsmentioning

confidence: 99%

Semiconductor spin qubits

et al. 2023

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The spin degree of freedom of an electron or a nucleus is one of the most basic properties of nature and functions as an excellent qubit, as it provides a natural two-level system that is insensitive to electric fields, leading to long quantum coherence times. This coherence survives when the spin is isolated and controlled within nanometer-scale, lithographically fabricated semiconductor devices, enabling the existing microelectronics industry to help advance spin qubits into a scalable technology. Driven by the burgeoning field of quantum information science, worldwide efforts have developed semiconductor spin qubits to the point where quantum state preparation, multiqubit coherent control, and single-shot quantum measurement are now routine. The small size, high density, long coherence times, and available industrial infrastructure of these qubits provide a highly competitive candidate for scalable solid-state quantum information processing. We review the physics of semiconductor spin qubits, focusing not only on the early achievements of spin initialization, control, and readout in GaAs quantum dots, but also on recent advances in Si and Ge spin qubits, including improved charge control and readout, coupling to other quantum degrees of freedom, and scaling to larger system sizes. We begin by introducing the four major types of spin qubits: single spin qubits, donor spin qubits, singlet-triplet spin qubits, and exchange-only spin qubits. We then review the mesoscopic physics of quantum dots, including single-electron charging, valleys, and spin-orbit coupling. We next give a comprehensive overview of the physics of exchange interactions, a crucial resource for single-and two-qubit control in spin qubits. The bulk of this review is centered on the presentation of results from each major spin qubit type, the present limits of fidelity, and a brief overview of alternative spin qubit platforms. We then give a physical description of the impact of noise on semiconductor spin qubits, aided in large part by an introduction to the filter function formalism. Lastly, we review recent efforts to hybridize spin qubits with superconducting systems, including charge-photon coupling, spin-photon coupling, and long-range cavity-mediated spin-spin interactions. Cavity-based readout approaches are also discussed. This review is intended to give an appreciation for the future prospects of semiconductor spin qubits, while highlighting the key advances in mesoscopic physics over the past two decades that underlie the operation of modern quantum-dot and donor-spin qubits. CONTENTS1. Spin transport, spin SWAPs, and spin-CTAP 24 2. Superexchange 25 3. Capacitive and electric dipole-dipole couplings 26 4. Cavity QED 26 V. Quantum gates and quantum circuits 26 A. Loss-DiVincenzo single spin qubits 27 1. Initialization and readout 27 2. Single-qubit gates 28 3. Two-qubit gates 29 4. Limits of fidelity -randomized benchmarking 30 B. Donor spin qubits 31 1. Donor electron spin initialization and readout 31 2. Donor electron spin single-qu...

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Section: Capacitive and Electric Dipole-dipole Couplingsmentioning

confidence: 99%

Semiconductor spin qubits

et al. 2023

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“…In the following, we always consider a gate performed on qubit 1 (1 and 2) for single-qubit (two-qubit) operations and their corresponding crosstalk on the nearest neighbor qubit 2 (3) in form of an unwanted magnetic driving field on the neighboring qubit which for EDSR can be capacitively induced [25,26] by the actual driving field B y1,1 (B y1,2 ) applied on the corresponding gate [27].…”

Section: Crosstalk Analysismentioning

confidence: 99%

Crosstalk analysis for single-qubit and two-qubit gates in spin qubit arrays

Heinz,

Burkard

2021

Preprint

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Scaling up spin qubit systems requires high-fidelity single-qubit and two-qubit gates. Gate fidelities exceeding 98% were already demonstrated in silicon based single and double quantum dots, whereas for the realization of larger qubit arrays crosstalk effects on neighboring qubits must be taken into account. We analyze qubit fidelities impacted by crosstalk when performing single-qubit and two-qubit operations on neighbor qubits with a simple Heisenberg model. Furthermore we propose conditions for driving fields to robustly synchronize Rabi oscillations and avoid crosstalk effects. In our analysis we also consider next to nearest neighbor crosstalk and show that double synchronization leads to a restricted choice for the driving field strength, exchange interaction, and thus gate time. Considering realistic experimental conditions we propose a set of parameter values to perform a nearly crosstalk-free CNOT gate and so open up the pathway to scalable quantum computing devices.

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“…We now introduce the magnetic crosstalk field B CT acting on a qubit operation which for EDSR can be capacitively induced [30,31] by a driving field applied on nearby qubits [8]. The case of ESR with a global drive is also covered by our model.…”

Section: Crosstalk Analysismentioning

confidence: 99%

Crosstalk analysis for simultaneously driven two-qubit gates in spin qubit arrays

Heinz,

Burkard

2021

Preprint

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One of the challenges when scaling up semiconductor-based quantum processors consists in the presence of crosstalk errors caused by control operations on neighboring qubits. In previous work, crosstalk in spin qubit arrays has been investigated for non-driven single qubits near individually driven quantum gates and for two simultaneously driven single-qubit gates. Nevertheless, simultaneous gates are not restricted to single-qubit operations but also include frequently used two-qubit gates such as the CNOT gate. We analyse the impact of crosstalk drives on qubit operations, such as the CNOT and CPHASE gates. We investigate the case of parallel Y and CNOT gates, and we also consider a two-dimensional arrangement of two parallel CNOT gates and find unavoidable crosstalk. To minimize crosstalk errors, we develop appropriate control protocols.

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Programable two-qubit gates in capacitively coupled flopping-mode spin qubits

Cited by 15 publications

References 52 publications

Semiconductor spin qubits

Semiconductor spin qubits

Crosstalk analysis for single-qubit and two-qubit gates in spin qubit arrays

Crosstalk analysis for simultaneously driven two-qubit gates in spin qubit arrays

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