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High-fidelity detection of charge transitions in quantum dots (QDs) is a key ingredient in solid state quantum computation. We demonstrate high-bandwidth radio-frequency charge detection in bilayer graphene quantum dots (QDs) using a…

Charge noise is one of the main sources of environmental decoherence for spin qubits in silicon, presenting a major obstacle in the path towards highly scalable and reproducible qubit fabrication. Here we demonstrate in-depth…

We probe local charge fluctuations in a semiconductor via laser spectroscopy on a nearby self-assembled quantum dot. We demonstrate that the quantum dot is sensitive to changes in the local environment at the single charge level. By…

In this paper, we explore an efficient online algorithm for quantum state estimation based on a matrix-exponentiated gradient method previously used in the context of machine learning. The state update is governed by a learning rate that…

Quantum Physics · Physics 2019-03-28 Akram Youssry , Christopher Ferrie , Marco Tomamichel

Accurate detection of quantum states is a vital step in the development of quantum computing. Image-charge detection of quantum states of electrons on liquid helium can potentially be used for the readout of a single-electron qubit;…

Quantum Physics · Physics 2021-01-12 Asem Elarabi , Erika Kawakami , Denis Konstantinov

A double quantum dot charge detector, with one dot Coulomb coupled to the electron to be detected and the other modulated by a time-dependent plunger voltage, is analyzed in a minimal model. The signal and noise of the detector are…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Tamas Geszti , Jozsef Zsolt Bernad

The analysis of data from gravitational wave detectors can be divided into three phases: search, characterization, and evaluation. The evaluation of the detection - determining whether a candidate event is astrophysical in origin or some…

General Relativity and Quantum Cosmology · Physics 2009-11-06 Tyson B. Littenberg , Neil J. Cornish

Gate-defined semiconductor quantum dots require an appropriate number of electrons to function as qubits. The number of electrons is usually tuned by analyzing charge stability diagrams, in which charge transitions manifest as edges.…

Mesoscale and Nanoscale Physics · Physics 2025-08-13 Fabian Hader , Fabian Fuchs , Sarah Fleitmann , Karin Havemann , Benedikt Scherer , Jan Vogelbruch , Lotte Geck , Stefan van Waasen

In this paper we consider the problem of tracking the state of a quantum system via a continuous measurement. If the system Hamiltonian is known precisely, this merely requires integrating the appropriate stochastic master equation.…

Quantum Physics · Physics 2011-11-29 Jason F. Ralph , Kurt Jacobs , Charles D. Hill

We address the ultimate charge detection scheme with a quantum point contact. It is shown that a superposed input state is necessary to exploit the full sensitivity of a quantum point contact detector. The coherence of the input state…

Mesoscale and Nanoscale Physics · Physics 2015-06-11 Kang-Ho Lee , Kicheon Kang

We present an approach to Bayesian mean estimation of quantum states using hyperspherical parametrization and an experiment-specific likelihood which allows utilization of all available data, even when qubits are lost. With this method, we…

Quantum Physics · Physics 2017-04-26 Brian P. Williams , Pavel Lougovski

We present a simple and efficient Bayesian recursive algorithm for the data-pattern scheme for quantum state reconstruction, which is applicable to situations where measurement settings can be controllably varied efficiently. The algorithm…

Upon photo- or electrical-excitation, colloidal quantum dots (QDs) are often found in multi-carrier states due to multi-photon absorption and photo-charging of the QDs. While many of these multi-carrier states are observed in single-dot…

Radio-frequency (RF) reflectometry is implemented in hybrid semiconductor-superconductor nanowire systems designed to probe Majorana zero modes. Two approaches are presented. In the first, hybrid nanowire-based devices are part of a…

Sensitive charge detection has enabled qubit readout in solid-state systems. Recently, an alternative to the well-established charge detection via on-chip electrometers has emerged, based on in situ gate detectors and radio-frequency…

Mesoscale and Nanoscale Physics · Physics 2017-05-24 A. Rossi , R. Zhao , A. S. Dzurak , M. F. Gonzalez-Zalba

Bayesian inference is a widely used technique for real-time characterization of quantum systems. It excels in experimental characterization in the low data regime, and when the measurements have degrees of freedom. A decisive factor for its…

Quantum Physics · Physics 2025-07-10 Alexandra Ramôa , Raffaele Santagati , Nathan Wiebe

Semiconductor quantum dots are useful for controlling and observing quantum states and can also be used as sensors for reading out quantum bits and exploring local electronic states in nanostructures. However, challenges remain for the…

Mesoscale and Nanoscale Physics · Physics 2023-11-23 Yoshihiro Fujiwara , Motoya Shinozaki , Kazuma Matsumura , Kosuke Noro , Riku Tataka , Shoichi Sato , Takeshi Kumasaka , Tomohiro Otsuka

Time-resolved electron dynamics in coupled quantum dots is directly observed by a pulsed-gate technique. While individual gate voltages are modulated with periodic pulse trains, average charge occupations are measured with a nearby quantum…

Mesoscale and Nanoscale Physics · Physics 2010-11-12 D. Harbusch , S. Manus , H. P. Tranitz , W. Wegscheider , S. Ludwig

Estimating state of health is a critical function of a battery management system but remains challenging due to the variability of operating conditions and usage requirements of real applications. As a result, techniques based on fitting…

Systems and Control · Electrical Eng. & Systems 2025-02-17 Antti Aitio , Dominik Jöst , Dirk Uwe Sauer , David A. Howey

We measure current by counting single electrons tunneling through an InAs nanowire quantum dot. The charge detector is realized by fabricating a quantum point contact in close vicinity to the nanowire. The results based on electron counting…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 S. Gustavsson , I. Shorubalko , R. Leturcq , S. Schön , K. Ensslin