Spin-orbit Interactions for Singlet-Triplet Qubits in Silicon

Harvey-Collard, Patrick; Jacobson, Noah Tobias; Bureau-Oxton, Chloe; Jock, Ryan Michael; Srinivasa, Vanita; Mounce, Andrew; Ward, Daniel R.; Anderson, John M.; Manginell, Ronald P.; Wendt, Joel R.; Pluym, Tammy; Lilly, Michael; Luhman, Dwight; Pioro‐Ladrière, Michel; Carroll, Malcolm S.

doi:10.1103/physrevlett.122.217702

Cited by 56 publications

(46 citation statements)

References 47 publications

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“…As shown in Fig. 3, for t = 0.1 µeV, measured recently in Si/SiO 2 quantum dots [51,52], the probability of transfer is lowered to ≈ 0.95 at v ≈ 1 µeV/ns when the oscillations caused by interference of two transfer paths are dephased. While in Sec.…”

Section: Resultsmentioning

confidence: 64%

“…In presence of quasistatic noise (due to fluctuations of Overhauser splittings in the two dots), or the slowest components of 1/f noise that still lead to finite fluctuation of detuning during the transfer process, these oscillations become dephased, but the transfer probability is lowered compared to t = 0 case. This could make the window of v allowing for highfidelity electron transfer quite narrow in SiMOS devices, where such values of t were measured [51,52], unless one chooses the magnetic field direction and geometry of the structure that makes t smaller.…”

Section: Discussionmentioning

confidence: 99%

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Adiabatic electron charge transfer between two quantum dots in presence of 1/f noise

Krzywda

Cywiński

2020

Phys. Rev. B

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Controlled adiabatic transfer of a single electron through a chain of quantum dots has been recently achieved in GaAs and Si/SiGe based quantum dots, opening prospects for turning stationary spin qubits into mobile ones, and solving in this way the problem of long-distance communication between quantum registers in a scalable quantum computing architecture based on quantum dots. We consider theoretically the process of such an electron transfer between two tunnel-coupled quantum dots, focusing on control by slowly varying the detuning of energy levels in the dots. We take into account the fluctuations in detuning caused by 1/f -type noise that is ubiquitous in semiconductor nanostructures, and analyze their influence on probability of successful transfer of an electron in a spin eigenstate. With numerical and analytical calculations we show that probability of electron not being transferred due to 1/f β noise in detuning is ∝ σ 2 t β−1 /v, where σ characterizes the noise amplitude, t is the interdot tunnel coupling, and v is the detuning sweep rate. Interestingly, this means that the noise-induced errors in charge transfer are independent of t for 1/f noise. For realistic parameters taken from experiments on silicon-based quantum dots, we obtain the minimal probability of charge transfer failure between a pair of dots is limited by 1/f noise in detuning to be the on order of 0.01. This means that in order to reliably transfer charges across many quantum dots, charge noise in the devices should be further suppressed, or tunnel couplings should be increased, in order to allow for faster transfer (and less exposure to noise), while not triggering the deterministic Landau-Zener excitation. arXiv:1909.11780v2 [cond-mat.mes-hall]

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Section: Resultsmentioning

confidence: 64%

Section: Discussionmentioning

confidence: 99%

Adiabatic electron charge transfer between two quantum dots in presence of 1/f noise

Krzywda

Cywiński

2020

Phys. Rev. B

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“…23 suggests that electrical control of the nuclear-spin qubit should be possible either by relying on an inhomogeneous magnetic field (artificial spin-orbit interaction), or by relying on intrinsic spin-orbit interaction. In a simple phenomenological picture, spin-orbit interaction can influence the dot-donor system in two ways; both effects have been observed in silicon double quantum dots [37][38][39][40] . On the one hand, it renormalizes the g-factor (with few percents), potentially making it anisotropic and different at the donor and in the dot.…”

Section: Discussionmentioning

confidence: 99%

Hyperfine-assisted decoherence of a phosphorus nuclear-spin qubit in silicon

2019

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The nuclear spin of a phosphorus atom in silicon has been used as a quantum bit in various quantum-information experiments. It has been proposed that this nuclear-spin qubit can be efficiently controlled by an ac electric field, when embedded in a two-electron dot-donor setup subject to intrinsic or artificial spin-orbit interaction. Exposing the qubit to control electric fields in that setup exposes it to electric noise as well. In this work, we describe the effect of electric noise mechanisms, such as phonons and 1/f charge noise, and estimate the corresponding decoherence time scales of the nuclear-spin qubit. We identify a promising parameter range where the electrical single-qubit operations are at least an order of magnitude faster then the decoherence. In this regime, decoherence is dominated by dephasing due to 1/f charge noise. Our results facilitate the optimized design of nanostructures to demonstrate electrically driven nuclear spin resonance.

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“…On the other hand, the GaAs system can form a large dot, although the short coherence time is problematic [96]. The spin-orbit coupling [97,98] could be problematic in Step II. However, we believe that the study of clever pulse schemes to mitigate spin-orbit coupling is beyond the scope of the paper.…”

Section: Discussionmentioning

confidence: 99%

Theoretical Study on Spin-Selective Coherent Electron Transfer in a Quantum Dot Array

2019

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Recently, we proposed the spin-selective coherent electron transfer in a silicon-quantum-dot array. It requires temporal tuning of two pulses of an oscillating magnetic field and gate voltage control. This paper proposes a simpler method that requires a single pulse of oscillating magnetic field and gate voltage control. We examined the robustness of the control against the error in the pulse amplitude and the effect of the excited states relaxation to the control efficiency. In addition, we propose a novel control method based on a shortcuts-to-adiabaticity protocol, which utilizes two pulses but requires temporal control of the pulse amplitude for only one of them. We compared their efficiencies under the effect of realistic pulse amplitude errors and relaxation.

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Spin-orbit Interactions for Singlet-Triplet Qubits in Silicon

Cited by 56 publications

References 47 publications

Adiabatic electron charge transfer between two quantum dots in presence of 1/f noise

Adiabatic electron charge transfer between two quantum dots in presence of 1/f noise

Hyperfine-assisted decoherence of a phosphorus nuclear-spin qubit in silicon

Theoretical Study on Spin-Selective Coherent Electron Transfer in a Quantum Dot Array

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