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Quantum detection and estimation theory
TLDR
In this article, the optimum procedure for choosing between two hypotheses, and an approximate procedure valid at small signal-to-noise ratios and called threshold detection, are presented, and a quantum counterpart of the Cramer-Rao inequality of conventional statistics sets a lower bound to the mean-square errors of such estimates.Abstract:
A review. Quantum detection theory is a reformulation, in quantum-mechanical terms, of statistical decision theory as applied to the detection of signals in random noise. Density operators take the place of the probability density functions of conventional statistics. The optimum procedure for choosing between two hypotheses, and an approximate procedure valid at small signal-to-noise ratios and called threshold detection, are presented. Quantum estimation theory seeks best estimators of parameters of a density operator. A quantum counterpart of the Cramer-Rao inequality of conventional statistics sets a lower bound to the mean-square errors of such estimates. Applications at present are primarily to the detection and estimation of signals of optical frequencies in the presence of thermal radiation.read more
Citations
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Journal ArticleDOI
Optical hybrid approaches to quantum information
TL;DR: This article reviews recent hybrid approaches to optical quantum information processing, in which both discrete and continuous degrees of freedom are exploited, potentially adding weak or measurement-induced nonlinearities to the toolbox.
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On quantumness in multi-parameter quantum estimation
TL;DR: In this paper, the authors derived a measure of quantumness in quantum multi-parameter estimation problems, and showed that the ratio between the mean Uhlmann Curvature and the Fisher Information provides a figure of merit which estimates the amount of incompatibility arising from the quantum nature of the underlying physical system.
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Measurement of the internal state of a single atom without energy exchange
TL;DR: In this paper, the authors demonstrate optical detection of an atomic qubit with significantly less than one spontaneous scattering event and quantitatively measure how much spontaneous scattering has occurred, and obtain a detection error below 10 per cent while scattering less than 0.2 photons on average.
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Risk Analysis of Trojan-Horse Attacks on Practical Quantum Key Distribution Systems
TL;DR: This work presents a risk analysis of Trojan-horse attacks on quantum key distribution systems based on extensive spectral measurements, and indicates the existence of wavelength regimes, where the attacker gains considerable advantage as compared to launching an attack at 1550 nm.
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Quantum stream cipher by the Yuen 2000 protocol: Design and experiment by an intensity-modulation scheme
TL;DR: This paper presents a simple cryptanalysis based on an attacker's heterodyne measurement and a quantum unambiguous measurement to make clear the strength of the Y-00 protocol in real communication.
References
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Coherent and incoherent states of the radiation field
TL;DR: In this article, the photon statistics of arbitrary fields in fully quantum-mechanical terms are discussed, and a general method of representing the density operator for the field is discussed as well as a simple formulation of a superposition law for photon fields.
Book
Detection, Estimation, And Modulation Theory
TL;DR: Detection, estimation, and modulation theory, Detection, estimation and modulation theorists, اطلاعات رسانی کشاورزی .
Journal ArticleDOI
Description of States in Quantum Mechanics by Density Matrix and Operator Techniques
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On the problems of the most efficient tests of statistical hypotheses.
J. Neyman,E. S. Pearson +1 more
TL;DR: The problem of testing statistical hypotheses is an old one as discussed by the authors, and its origin is usually connected with the name of Thomas Bayes, who gave the well-known theorem on the probabilities a posteriori of the possible causes of a given event.