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The quantum properties of quantum measurements are indispensable resources in quantum information processing and have drawn extensive research interest. The conventional approach to reveal the quantum properties relies on the reconstruction…

Quantum Physics · Physics 2021-12-01 Liang Xu , Huichao Xu , Jie Xie , Hui Li , Lin Zhou , Feixiang Xu , Lijian Zhang

The measurement precision of modern quantum simulators is intrinsically constrained by the limited set of measurements that can be efficiently implemented on hardware. This fundamental limitation is particularly severe for quantum…

Quantum Physics · Physics 2020-07-01 Giacomo Torlai , Guglielmo Mazzola , Giuseppe Carleo , Antonio Mezzacapo

During a continuous measurement, quantum systems can be described by a stochastic Schr\"odinger equation which, in the appropriate limit, reproduces the von Neumann wave-function collapse. The average behavior on the ensemble of all…

Condensed Matter · Physics 2009-10-30 Carlo Presilla , Ubaldo Tanbini

We present an inference method utilizing artificial neural networks for parameter estimation of a quantum probe monitored through a single continuous measurement. Unlike existing approaches focusing on the diffusive signals generated by…

We review a recently developed theoretical approach to the experimental detection and quantification of bipartite quantum correlations between a qubit and a d dimensional system. Specifically, introducing a properly designed measure Q, the…

Quantum Physics · Physics 2012-12-06 Davide Girolami , Ruggero Vasile , Gerardo Adesso

This dissertation studies the statistics and modeling of a quantum system probed by a coherent laser field. We focus on an ensemble of qubits dispersively coupled to a traveling wave light field. The first research topic explores the…

Quantum Physics · Physics 2013-01-29 Robert L. Cook

Performance of quantum process estimation is naturally limited to fundamental, random, and systematic imperfections in preparations and measurements. These imperfections may lead to considerable errors in the process reconstruction due to…

Quantum Physics · Physics 2010-03-16 M. Mohseni , A. T. Rezakhani , J. T. Barreiro , P. G. Kwiat , A. Aspuru-Guzik

In quantum physics, measurements give random results and yield a corresponding random back action on the state of the system subject to measurement. If a quantum system is probed continuously over time, its state evolves along a stochastic…

Quantum Physics · Physics 2016-03-28 N. Foroozani , M. Naghiloo , D. Tan , K. Mølmer , K. W. Murch

In this paper we present a method for representing continuous signals with high precision by interpolating quantum state amplitudes. The method is inspired by the Nyquist-Shannon sampling theorem, which links continuous and discrete time…

Quantum Physics · Physics 2022-03-17 Charlee Stefanski , Vanio Markov , Constantin Gonciulea

One of the most important quantities characterizing the microscopic properties of quantum systems are dynamical correlation functions. These correlations are obtained by time-evolving a perturbation of an eigenstate of the system, typically…

Quantum Physics · Physics 2025-02-26 Reinis Irmejs , Raul A. Santos

Quantum measurements of physical quantities are usually described as ideal measurements. However, only a few measurements fulfil the conditions of ideal measurements. The aim of the present work is to describe real position measurements…

Quantum Physics · Physics 2019-01-17 Klaus Wick

In this work we introduce a general scheme for measurement based quantum computation in continuous variables. Our approach does not necessarily rely on the use of ancillary cluster states to achieve its aim, but rather on the detection of a…

Quantum Physics · Physics 2017-02-01 Giulia Ferrini , Jonathan Roslund , Francesco Arzani , Claude Fabre , Nicolas Treps

We consider the simultaneous and continuous measurement of qubit observables $\sigma_z$ and $\sigma_z\cos\varphi + \sigma_x\sin\varphi$, focusing on the temporal correlations of the two output signals. Using quantum Bayesian theory, we…

The Gaussian state description of continuous variables is adapted to describe the quantum interaction between macroscopic atomic samples and continuous-wave light beams. The formalism is very efficient: a non-linear differential equation…

Quantum Physics · Physics 2007-05-23 L. B. Madsen , K. Mølmer

We investigate the advantages of using two independent, linear detectors for continuous quantum measurement. For single-shot quantum measurement, the measurement is maximally efficient if the detectors are twins. For weak continuous…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Andrew N. Jordan , Markus Buttiker

We show that, for any n, there are m-outcome quantum correlations, with m>n, which are stronger than any nonsignaling correlation produced from selecting among n-outcome measurements. As a consequence, for any n, there are m-outcome quantum…

Quantum Physics · Physics 2016-10-17 Matthias Kleinmann , Adan Cabello

Measurements in the quantum domain can exceed classical notions. This concerns fundamental questions about the nature of the measurement process itself, as well as applications, such as their function as building blocks of quantum…

Quantum Physics · Physics 2023-02-02 Jan Sperling , Ilaria Gianani , Marco Barbieri , Elizabeth Agudelo

Measurements provide a novel mechanism for generating the entanglement resource necessary for performing scalable quantum computation. Recently, we proposed a method for performing parity measurements in a coupled quantum dot system. In…

Quantum Physics · Physics 2009-11-13 Avinash Kolli , Simon C. Benjamin , Brendon W. Lovett , Thomas M. Stace

The correlation function in quantum systems plays a vital role in decoding their properties and gaining insights into physical phenomena. Its interpretation corresponds to the propagation of particle excitations between space-time, similar…

Quantum Physics · Physics 2024-05-14 Yuan Feng , Xi Chen , Yongcheng Ding

Entanglement plays a fundamental role in quantum physics and information processing. Here, we develop an unbiased estimator for mixed-state entanglement in the few-shot scenario and directly estimate it using random unitary evolution in a…

Quantum Physics · Physics 2024-07-09 Gong-Chu Li , Lei Chen , Si-Qi Zhang , Xu-Song Hong , You Zhou , Geng Chen , Chuan-Feng Li , Guang-Can Guo