Radio-frequency measurement in semiconductor quantum computation

Han, Tianyi; Chen, MingBo; Cao, Gang; Li, Hai-Ou; Xiao, Ming; Guo, Guo-Ping

doi:10.1007/s11433-017-9019-9

Cited by 9 publications

(9 citation statements)

References 60 publications

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“…A typical state-of-the-art charge sensor with a transconductance amplifiuer at room temperature (RT) can achieve a charge sensitivity down to 820 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\mu e/\sqrt {{\rm{Hz}}} $\end{document} for a 30 kHz bandwidth [ 140 ]. To improve its performance, several approaches have been investigated [ 141 ].…”

Section: Challenges and Opportunitiesmentioning

confidence: 99%

Semiconductor quantum computation

Zhang

Cao

et al. 2018

National Science Review

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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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Section: Challenges and Opportunitiesmentioning

confidence: 99%

Semiconductor quantum computation

Zhang

Cao

et al. 2018

National Science Review

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150

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“…1a. The charge state of the double dot is monitored by a nearby quantum point contact (QPC) [30]. The QPC is biased using a 0.4-mV DC voltage, and a modulation signal with amplitude of 0.5 mV and a frequency of 183 Hz is superimposed on gate R. The QPC transconductance dI QPC /dV R is measured using a lock-in amplifier operated in sync with the modulation signal [31].…”

Section: Methodsmentioning

confidence: 99%

Enhanced readout of spin states in double quantum dot

et al. 2017

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“…In Si/SiO2 quantum dots, EVS can range from 0.1 to 1 meV [18] [19] and Γ 𝑣 is expected to be as fast as 100 MHz [13] [17]. Consequently, a direct measurement of intervalley relaxation in quantum dots has never been achieved, as the relaxation rate is just outside the bandwidth of stateof-the-art charge detection with rf reflectometry [20] [21] [22] and far outside the bandwidth of standard capacitive charge sensing measurements. However, the valley splitting in Si/SiGe-based quantum dots is almost universally smaller than their Si/SiO2 counterparts [23] [24] [25] [26] [27] and could result in a relaxation rate slow enough to capture in real-time.…”

Section: Introductionmentioning

confidence: 99%

Direct Measurement of Electron Intervalley Relaxation in a Si/Si - Ge Quantum Dot

et al. 2020

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The presence of non-degenerate valley states in silicon can drastically affect electron dynamics in silicon-based heterostructures, leading to electron spin relaxation and spin-valley coupling. In the context of solid-state spin qubits, it is important to understand the interplay between spin and valley degrees of freedom to avoid or alleviate these decoherence mechanisms. Here we report the observation of relaxation from the excited valley state to the ground state in a Si/SiGe quantum dot, at zero magnetic field. Valley state read-out is aided by a valley-dependent tunneling effect, which we attribute to valley-orbit coupling. We find a long intervalley relaxation time of 12.0 ± 0.3 ms, a value that is unmodified when a magnetic field is applied. Furthermore, we compare our findings with the spin relaxation time and find that the spin-valley "hot spot" relaxation is roughly four times slower than intervalley relaxation, consistent with established theoretical predictions.The precision of this technique, adapted from electron spin read-out via energy-dependent tunneling, is an improvement over indirect valley relaxation measurements and could be a useful probe of valley physics in spin and valley qubit implementations.

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Radio-frequency measurement in semiconductor quantum computation

Cited by 9 publications

References 60 publications

Semiconductor quantum computation

Semiconductor quantum computation

Enhanced readout of spin states in double quantum dot

Direct Measurement of Electron Intervalley Relaxation in a Si/Si - Ge Quantum Dot

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