Robust Single-Shot Spin Measurement with 99.5% Fidelity in a Quantum Dot Array

Nakajima, Takashi; Delbecq, Matthieu; Otsuka, Takeshi; Stano, Peter; Amaha, S.; Yoneda, Jun; Noiri, Akito; Kawasaki, Kento; Takeda, Kenta; Allison, Giles; Ludwig, Arne; Wieck, A. D.; Loss, Daniel; Tarucha, Seigo

doi:10.1103/physrevlett.119.017701

Cited by 59 publications

(74 citation statements)

References 40 publications

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“…To this end, we consider the harmonic heterostructure confinement, Eq. (14). In this case, the full three-dimensional model has an analytical solution for arbitrary magnetic field (see Appendix B), which we can use as a benchmark for the effective two-dimensional model.…”

Section: Accuracy Of the Perturbative Resultsmentioning

confidence: 99%

“…9 This, so far missing, spectroscopic tool is essential for a quantitative assessment of, for example, the spin-orbit fields, 10 or the hyperfine electron-nuclear interaction, and the related limits on the spin relaxation, 11,12 dephasing, 13 or measurement fidelities. 14 To illustrate the power of these tools, we use them here to fit the strengths of the spin-orbit interactions in a GaAs quantum dot. We find excellent agreement with values extracted from an independent fit based on the directional variation of the spin relaxation time done in Ref.…”

Section: Introductionmentioning

confidence: 99%

“…Exact spectrum of the 3D harmonic modelWe now consider the 3D model with a harmonic confinement in all three directions, that is the one described by Eqs (13). and(14). The energies can be obtained by a straightforward analogy of the previous subsection applied for d = 3.…”

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confidence: 99%

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Orbital effects of a strong in-plane magnetic field on a gate-defined quantum dot

et al. 2019

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We theoretically investigate the orbital effects of an in-plane magnetic field on the spectrum of a quantum dot embedded in a two-dimensional electron gas (2DEG). We derive an effective twodimensional Hamiltonian where these effects enter in proportion to the flux penetrating the 2DEG. We quantify the latter in detail for harmonic, triangular, and square potential of the heterostructure. We show how the orbital effects allow one to extract a wealth of information, for example, on the heterostructure interface, the quantum dot size and orientation, and the spin-orbit fields. We illustrate the formalism by extracting this information from recent measured data [L. C. Camenzind, et al., arXiv:1804.00162; Nat. Commun. 9, 3454 (2018)]. arXiv:1804.00128v2 [cond-mat.mes-hall]

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Section: Accuracy Of the Perturbative Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Orbital effects of a strong in-plane magnetic field on a gate-defined quantum dot

et al. 2019

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“…Then combined with MW bursts, Koppens et al demonstrated the first driven coherent single spin rotations in 2006 [45]. Furthermore, the visibility of readout in the singlet-triplet basis can be enhanced by charge state latching [46,47] and intermediate excited states [48]. In Harvey-Collard et al's work, they achieved a measurement fidelity as high as 99.86% via charge state latching, and in 2018, Fogarty et al demonstrated measuring a spin-1/2 qubit using this new method [49].…”

Section: Spin-1/2 Qubitmentioning

confidence: 99%

Semiconductor quantum computation

Zhang

Cao

et al. 2018

National Science Review

150

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Semiconductors, a significant type of material in the information era, are becoming more and more powerful in the field of quantum information. In the last decades, semiconductor quantum computation was investigated thoroughly across the world and developed with a dramatically fast speed. The researches vary from initialization, control and readout of qubits, to the architecture of fault tolerant quantum computing. Here, we first introduce the basic ideas for quantum computing, and then discuss the developments of single-and twoqubit gate control in semiconductor. Till now, the qubit initialization, control and readout can be realized with relatively high fidelity and a programmable two-qubit quantum processor was even demonstrated. However, to further improve the qubit quality and scale it up, there are still some challenges to resolve such as the improvement of readout method, material development and scalable designs. We discuss these issues and introduce the forefronts of progress. Finally, considering the positive trend of the research on semiconductor quantum devices and recent theoretical work on the applications of quantum computation, we anticipate that semiconductor quantum computation may develop fast and will have a huge impact on our lives in the near future.

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“…In this article we are concerned with the effects of the in-plane magnetic field on the spin, rather than orbital, structure of the states. Such an analysis requires 5 We note that the name and interpretation of the quantity Φ is motivated by the form of Eq. (16).…”

Section: Spin-dependent Perturbationsmentioning

confidence: 99%

g -factor of electrons in gate-defined quantum dots in a strong in-plane magnetic field

et al. 2018

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We analyze orbital effects of an in-plane magnetic field on the spin structure of states of a gated quantum dot based in a two-dimensional electron gas. Starting with a k·p Hamiltonian, we perturbatively calculate these effects for the conduction band of GaAs, up to the third power of the magnetic field. We quantify several corrections to the g-tensor and reveal their relative importance. We find that for typical parameters, the Rashba spin-orbit term and the isotropic term, H43 ∝ P 2 B · σ, give the largest contributions in magnitude. The in-plane anisotropy of the g-factor is, on the other hand, dominated by the Dresselhaus spin-orbit term. At zero magnetic field, the total correction to the g-factor is typically 5-10% of its bulk value. In strong in-plane magnetic fields, the corrections are modified appreciably. arXiv:1808.03963v2 [cond-mat.mes-hall] 4 Dec 2018 3 We stick here to the triangular heterostructure confinement in Eq. (4) and do not discuss in the main text, for the sake of brevity, other confinement types considered in Ref. 22. We give results for a symmetric confinement in App. D. 4 The corrections resulting from such terms are expected to be much smaller than the terms denoted gz (see below), which are of similar origin and which are subdominant.

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Robust Single-Shot Spin Measurement with 99.5% Fidelity in a Quantum Dot Array

Cited by 59 publications

References 40 publications

Orbital effects of a strong in-plane magnetic field on a gate-defined quantum dot

Orbital effects of a strong in-plane magnetic field on a gate-defined quantum dot

Semiconductor quantum computation

g -factor of electrons in gate-defined quantum dots in a strong in-plane magnetic field

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