Low-frequency charge noise in Si/SiGe quantum dots

Connors, Elliot J.; Nelson, J. K.; Qiao, Haifeng; Edge, L. F.; Nichol, John

doi:10.1103/physrevb.100.165305

Cited by 119 publications

(84 citation statements)

References 56 publications

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“…The first spectrum shows a 1/f β behavior, with β = 1.14, which is close to the 1/f behavior expected for a uniform distribution of fluctuating two-level systems (TLSs) in the environment [29]. It is worth noting that the chemical potential fluctuation at 1 Hz is lower than 1 μeV/ √ Hz, which compares favorably with the lowest potential-fluctuation values reported in the literature for silicon, which are in the 2-5 μeV/ √ Hz range at 350 mK [30][31][32]34]. The second spectrum shows a stronger deviation from 1/f noise.…”

Section: B Low-frequency Charge Noise and Static Coulomb Disordersupporting

confidence: 80%

“…The second spectrum shows a stronger deviation from 1/f noise. To explain this, we use a more-refined model of charge noise that accounts for a nonuniform distribution of TLS activation energies compared with the temperature [30,33]. S μ is fit with a function of the form S μ = A/f β + B/f 2 /f 2 c + 1.…”

Section: B Low-frequency Charge Noise and Static Coulomb Disordermentioning

confidence: 99%

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Charge Detection in an Array of CMOS Quantum Dots

et al. 2020

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The recent development of arrays of quantum dots in semiconductor nanostructures highlights the progress of quantum devices toward a large scale. However, how to realize such arrays on a scalable platform such as silicon is still an open question. One of the main challenges lies in the detection of charges within the array. It is a prerequisite to initialize a desired charge state and read out spins through spin-to-charge conversion mechanisms. In this work, we use two methods based on either a single-lead charge detector or a reprogrammable single-electron transistor. By these methods, we study the charge dynamics and sensitivity by performing single-shot detection of the charge. Finally, we can probe the charge stability at any node of a linear array and assess the Coulomb disorder in the structure. We find an electrochemical potential fluctuation induced by charge noise comparable to that reported in other silicon quantum dots.

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Section: B Low-frequency Charge Noise and Static Coulomb Disordersupporting

confidence: 80%

Section: B Low-frequency Charge Noise and Static Coulomb Disordermentioning

confidence: 99%

Charge Detection in an Array of CMOS Quantum Dots

et al. 2020

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“…Recently reported values of √ S 1 for charge noise affecting Si/SiGe quantum dots falls into range √ S 1 = S(1 Hz) ≈ 0.2 − 2 µeV/Hz 1/2 [33,36,[65][66][67], with 1/ω behavior of the power spectral density in frequency range ω ∼ t. As we have estimated in the previous Section, such noise is already sufficient to significantly limit the adiabatic transition probability at low and moderate sweep speed. On the other hand, the noiseless Landau-Zener process of nonadiabtic transition becomes relevant at high sweep speed.…”

Section: Resultsmentioning

confidence: 98%

“…Let us notice now that typical order of magnitude of √ S 1 is 1 µeV/Hz 1/2 [33,36,[65][66][67], while maximal detuning sweep velocities allowing for fast and high-probability noiseless transfer for typical t ≈ 10 µeV in Si QDs are of the order of 10-100 µeV/ns. Using these natural units for S 1 and v we have…”

Section: B Analytical Approach To Calculation Of Noise-induced Transmentioning

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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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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“…Empirically, semiconductor qubits are often limited by 1/f charge noise [30,31,32], which in turn leads to a power spectral density of exchange fluctuations S J (f ) = A 2 J /f . Therefore we will focus on modeling the expected exchange noise amplitude A J ; in Appendix E we discuss the connection between this quantity and γ for different experiments.…”

Section: Tqd Qubit Operation and Key Quantities For Spin-photon Couplingmentioning

confidence: 99%

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

Pan

Keating²,

Gyure³

et al. 2020

Quantum Sci. Technol.

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Triple quantum dots (TQDs) are promising semiconductor spin qubits because of their all-electrical control via fast, tunable exchange interactions and immunity to global magnetic fluctuations. These qubits couple to photons in the resonant exchange (RX) regime, when exchange is simultaneously active on both qubit axes. However, most theoretical work has been based on phenomenological Fermi-Hubbard models, which may not fully capture the complexity of the qubit spin-charge states in this regime. Here we investigate exchange in Si/SiGe and GaAs TQDs using full configuration interaction (FCI) calculations which better describe practical device operation. We show that high exchange operation in general, and the RX regime in particular, can differ significantly from simple models, presenting new challenges and opportunities for spin-photon coupling. We highlight the impact of device electrostatics and effective mass on exchange and identify a new operating point (XRX) where strong spin-photon coupling is most likely to occur in Si/SiGe TQDs. Based on our numerical results, we analyze the feasibility of a remote entanglement cavity iSWAP protocol and discuss design pathways for improving fidelity. Our analysis provides insight into the requirements for TQD spin-photon transduction and demonstrates more generally the necessity of accurate modeling of exchange in spin qubits. ‡ Present address:

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Low-frequency charge noise in Si/SiGe quantum dots

Cited by 119 publications

References 56 publications

Charge Detection in an Array of CMOS Quantum Dots

Charge Detection in an Array of CMOS Quantum Dots

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

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

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