Resonant exchange operation in triple-quantum-dot qubits for spin–photon transduction

Pan, Alan; Keating, Tyler; Gyure, Mark F.; Pritchett, Emily; Quinn, S. M.; Ross, Richard S.; Ladd, Thaddeus D.; Kerckhoff, Joseph

doi:10.1088/2058-9565/ab86c9

Cited by 21 publications

(17 citation statements)

References 50 publications

(103 reference statements)

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“…As discussed above, it is likely that other parameters of the dots are changing or that the capacitance matrix may require further refinement. More sophisticated modeling of the electrostatic potential, using the actual computed potential, as opposed to a Gaussian approximation, and a more accurate calculation of exchange couplings beyond the two-spin HL framework [49] will likely also help to improve the model.…”

Section: Discussionmentioning

confidence: 99%

Coherent Multispin Exchange Coupling in a Quantum-Dot Spin Chain

et al. 2020

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Heisenberg exchange coupling between neighboring electron spins in semiconductor quantum dots provides a powerful tool for quantum information processing and simulation. Although so far unrealized, extended Heisenberg spin chains can enable long-distance quantum information transfer and the generation of nonequilibrium quantum states. In this work, we implement simultaneous, coherent exchange coupling between all nearest-neighbor pairs of spins in a quadruple quantum dot. The main challenge in implementing simultaneous exchange couplings is the nonlinear and nonlocal dependence of the exchange couplings on gate voltages. Through a combination of electrostatic simulation and theoretical modeling, we show that this challenge arises primarily due to lateral shifts of the quantum dots during gate pulses. Building on this insight, we develop two models that can be used to predict the confinement gate voltages for a desired set of exchange couplings. Although the model parameters depend on the number of exchange couplings desired (suggesting that effects in addition to lateral wave-function shifts are important), the models are sufficient to enable simultaneous and independent control of all three exchange couplings in a quadruple quantum dot. We demonstrate two-, three-, and four-spin exchange oscillations, and our data agree with simulations.

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Section: Discussionmentioning

confidence: 99%

Coherent Multispin Exchange Coupling in a Quantum-Dot Spin Chain

et al. 2020

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“…We note that v B determines the compensation pulses applied to LP and RP for virtual barrier control. We model J as an exponential function 31,32…”

Section: B S B S S Smentioning

confidence: 99%

“…The exchange interaction is modelled to be exponentially dependent on the barrier pulse amplitude J v ( )∝ e αv B 2 B (refs. 31,32 ). The micromagnet-induced single-qubit frequency shifts are approximated by linear functions within the voltage window of the CZ gate in the numerical simulations.…”

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confidence: 99%

Quantum logic with spin qubits crossing the surface code threshold

Xue

Russ

Samkharadze

et al. 2022

Nature

296

201

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High-fidelity control of quantum bits is paramount for the reliable execution of quantum algorithms and for achieving fault tolerance—the ability to correct errors faster than they occur1. The central requirement for fault tolerance is expressed in terms of an error threshold. Whereas the actual threshold depends on many details, a common target is the approximately 1% error threshold of the well-known surface code2,3. Reaching two-qubit gate fidelities above 99% has been a long-standing major goal for semiconductor spin qubits. These qubits are promising for scaling, as they can leverage advanced semiconductor technology4. Here we report a spin-based quantum processor in silicon with single-qubit and two-qubit gate fidelities, all of which are above 99.5%, extracted from gate-set tomography. The average single-qubit gate fidelities remain above 99% when including crosstalk and idling errors on the neighbouring qubit. Using this high-fidelity gate set, we execute the demanding task of calculating molecular ground-state energies using a variational quantum eigensolver algorithm5. Having surpassed the 99% barrier for the two-qubit gate fidelity, semiconductor qubits are well positioned on the path to fault tolerance and to possible applications in the era of noisy intermediate-scale quantum devices.

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“…Moreover, the exchange interaction may result in double occupancy [12,13] and leakage errors [14][15][16]. Nonetheless, it has been employed to reach large gate fidelities in quantum dot-based qubits [17,18] and forms the basis of an extending number of proposals for solid state quantum computation [19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Dynamical second-order noise sweetspots in resonantly driven spin qubits

Picó-Cortés

Platero

2021

Quantum

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Quantum dot-based quantum computation employs extensively the exchange interaction between nearby electronic spins in order to manipulate and couple different qubits. The exchange interaction, however, couples the qubit states to charge noise, which reduces the fidelity of the quantum gates that employ it. The effect of charge noise can be mitigated by working at noise sweetspots in which the sensitivity to charge variations is reduced. In this work we study the response to charge noise of a double quantum dot based qubit in the presence of ac gates, with arbitrary driving amplitudes, applied either to the dot levels or to the tunneling barrier. Tuning with an ac driving allows to manipulate the sign and strength of the exchange interaction as well as its coupling to environmental electric noise. Moreover, we show the possibility of inducing a second-order sweetspot in the resonant spin-triplet qubit in which the dephasing time is significantly increased.

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Resonant exchange operation in triple-quantum-dot qubits for spin–photon transduction

Cited by 21 publications

References 50 publications

Coherent Multispin Exchange Coupling in a Quantum-Dot Spin Chain

Coherent Multispin Exchange Coupling in a Quantum-Dot Spin Chain

Quantum logic with spin qubits crossing the surface code threshold

Dynamical second-order noise sweetspots in resonantly driven spin qubits

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