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The detection of the quantum dot charge state using a quantum point contact charge detector has opened a new exciting route for the investigation of quantum dot devices in recent years. In particular, time-resolved charge detection allowed…

Blind Source Separation (BSS) is an active domain of Classical Information Processing. The development of Quantum Information Processing has made possible the appearance of Blind Quantum Source Separation (BQSS). This article discusses some…

Quantum Physics · Physics 2022-10-04 Alain Deville , Yannick Deville

Estimating the overlap between an approximate wavefunction and a target eigenstate of the system Hamiltonian is essential for the efficiency of quantum phase estimation. In this work, we derive upper and lower bounds on this overlap using…

Quantum Physics · Physics 2025-03-18 Junan Lin , Artur F. Izmaylov

Quantum backaction refers to the disturbance of a quantum system caused by measuring it. In sequential measurements, this effect can accumulate and become significant, leading to nontrivial modifications of the system state and the…

Quantum Physics · Physics 2023-05-03 Le Bin Ho

The description of a measuring process, such as that which occurs when a quantum point contact (QPC) detector is influenced by a nearby external electron which can take up two possible positions, provides a interesting application of the…

Quantum Physics · Physics 2008-11-26 L. Stodolsky

We propose and theoretically investigate an alternative way to create the poor man's Majorana bound states (MBSs) introduced in Phys. Rev. B 86, 134528 (2012). Our proposal is based on two quantum dots (QDs) with strong electron-electron…

Mesoscale and Nanoscale Physics · Physics 2022-11-29 Athanasios Tsintzis , Rubén Seoane Souto , Martin Leijnse

The matrix product state (MPS) is utilized to study the ground state properties and quantum phase transitions (QPTs) of the one-dimensional quantum compass model (QCM). The MPS wavefunctions are argued to be very efficient descriptions of…

Strongly Correlated Electrons · Physics 2012-06-05 Guang-Hua Liu , Wei Li , Wen-Long You , Guang-Shan Tian , Gang Su

We revisit the old problem of exotic superconductivity as Cooper pairing with finite angular momentum emerging from a central potential. Based on some general considerations, we suggest that the phenomenonn is associated with interactions…

Superconductivity · Physics 2007-05-23 J. Quintanilla , B. L. Gyorffy

We investigate the effect of the charge state measurement of the Kondo singlet for a quantum dot transistor via a capacitively coupled quantum point contact detector. By employing the variational ansatz for the singlet ground state of the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Kicheon Kang

In this work we study the information provided by a detector click on the state of an initially excited two level system. By computing the time evolution of the corresponding conditioned probability beyond the rotating wave approximation,…

Quantum Physics · Physics 2012-04-10 Marco del Rey , Carlos Sabin , Juan Leon

We report high-bandwidth charge sensing measurements using a GaAs quantum point contact embedded in a radio frequency impedance matching circuit (rf-QPC). With the rf-QPC biased near pinch-off where it is most sensitive to charge, we…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 D. J. Reilly , C. M. Marcus , M. P. Hanson , A. C. Gossard

Medium-scale ensembles of coupled qubits offer a platform for near-term quantum technologies including computing, sensing, and the study of mesoscopic quantum systems. Atom-like emitters in solids have emerged as promising quantum memories,…

In a single-particle detection experiment, a wavefront impinges on a detector but observers only see a point response. The extent of the wavefront becomes evident only in statistical accumulation of many independent detections, with…

Quantum Physics · Physics 2017-06-26 Jonathan F. Schonfeld

By coupling a harmonic oscillator to a quantum system it is possible to perform a dispersive measurement that is quantum non-demolition (QND), with minimal backaction. A non-linear oscillator has the advantage of measurement gain, but what…

Mesoscale and Nanoscale Physics · Physics 2008-09-12 O. Naaman , J. Aumentado , L. Friedland , J. S. Wurtele , I. Siddiqi

We present finite bias measurements on a quantum dot coupled capacitively to a quantum point contact used as a charge detector. The transconductance signal measured in the quantum point contact at finite dot bias shows structure which…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 R. Schleser , E. Ruh , T. Ihn , K. Ensslin , D. C. Driscoll , A. C. Gossard

The protection of quantum states is challenging for non-orthogonal states especially in the presence of noises. The recent research breakthrough shows that this difficulty can be overcome by feedback control with weak measurements. However,…

Quantum Physics · Physics 2015-06-16 Y. Yang , X. Y. Zhang , J. Ma , X. X. Yi

A quantum system (quanton) traverses an interferometer with $N$ equally probable paths and interacts with another quantum system (detector) that stores path information in a set of symmetric states. In this interferometric framework, we…

Quantum Physics · Physics 2026-01-21 L. F. Melo , O. Jiménez , L. Neves

We present an efficient and robust protocol for quantum-enhanced sensing using a single qubit in the topological waveguide system. Our method relies on the topological-paired bound states, which are localized near the qubit and can be…

Quantum Physics · Physics 2025-08-08 Tao Zhang , Peng Xu , Jiazhong Hu , Xingze Qiu

Quantum measurements disturb the quantum system being measured, and this is known as measurement-induced backaction. In this work, we consider a double quantum dot monitored by a nearby quantum point contact where the measurement-induced…

Quantum Physics · Physics 2018-12-14 Wei Cui , Daoyi Dong

In this work we analyze how coherent transport through a Quantum Dot (QD) in the Kondo regime is affected by the weak capacitive interaction with a nearby biased Quantum Point Contact (QPC). We find that when the QD-QPC interaction is weak…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Alessandro Silva , Shimon Levit