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Various schemes have been proposed to overcome the drawback of the decoherence on quantum-enhanced parameter estimation. Here we suggest an alternative method, quantum feedback, to enhance the parameter precision of optimal quantum…

Quantum Physics · Physics 2015-06-24 Qiang Zheng , Li Ge , Yao Yao , Qi-jun Zhi

The Fisher information of a quantum observable is shown to be proportional to both (i) the difference of a quantum and a classical variance, thus providing a measure of nonclassicality; and (ii) the rate of entropy increase under Gaussian…

Quantum Physics · Physics 2009-10-31 Michael J. W. Hall

We formulate entropic measurements uncertainty relations (MURs) for a spin-1/2 system. When incompatible observables are approximatively jointly measured, we use relative entropy to quantify the information lost in approximation and we…

Quantum Physics · Physics 2018-05-11 Alberto Barchielli , Matteo Gregoratti

We present a framework for the detection and estimation of deformations applied to a grid of sources. Our formalism uses the Hamiltonian formulation of the quantum Fisher information matrix (\textsc{qfim}) as the figure of merit to quantify…

Quantum Physics · Physics 2018-02-07 Jasminder S. Sidhu , Pieter Kok

We discuss some applications of various versions of uncertainty relations for both discrete and continuous variables in the context of quantum information theory. The Heisenberg uncertainty relation enables demonstration of the EPR paradox.…

Quantum Physics · Physics 2014-10-23 Archan S. Majumdar , Tanumoy Pramanik

Information-theoretic definitions for noise and disturbance in quantum measurements were given in Phys. Rev. Lett. 112, 050401 (2014) and a state-independent noise-disturbance uncertainty relation was obtained. Here, we derive a tight…

We introduce spatial deformations to an array of light sources and study how the estimation precision of the interspacing distance, d, changes with the sources of light used. The quantum Fisher information (QFI) is used as the figure of…

Quantum Physics · Physics 2017-06-28 Jasminder S. Sidhu , Pieter Kok

Entropic uncertainty relations provide an information-theoretic framework for quantifying the fundamental indeterminacy inherent in quantum mechanics. We propose more stringent quantum-memory-assisted entropic uncertainty relations for…

Quantum Physics · Physics 2026-04-07 Qing-Hua Zhang , Cong Xu , Jing-Feng Wu , Shao-Ming Fei

Constructive techniques to establish state-independent uncertainty relations for the sum of variances of arbitrary two observables are presented. We investigate the range of simultaneously attainable pairs of variances, which can be applied…

Quantum Physics · Physics 2019-04-26 Konrad Szymański , Karol Życzkowski

We consider the problem of determining the weights of a quantum ensemble. That is to say, given a quantum system that is in a set of possible known states according to an unknown probability law, we give strategies to estimate the…

Quantum Physics · Physics 2010-02-01 J. I. de Vicente , J. Calsamiglia , R. Munoz-Tapia , E. Bagan

We prove a new sum uncertainty relation in quantum theory which states that the uncertainty in the sum of two or more observables is always less than or equal to the sum of the uncertainties in corresponding observables. This shows that the…

Quantum Physics · Physics 2009-11-13 A. K. Pati , P. K. Sahu

In this paper alternative formulations of the conventional uncertainty relation are studied in the context of decoherent histories. The results are given in terms of Shannon information. A variety of methods are developed to evaluate the…

High Energy Physics - Theory · Physics 2007-05-23 Bernhard Meister

Quantum mechanics gives a new breakthrough to the field of parameter estimation. In the realm of quantum metrology, the precision of parameter estimation is limited by the quantum Fisher information. We introduce the measures of partial…

Quantum Physics · Physics 2024-11-14 Dong-Ping Xuan , Zhong-Xi Shen , Wen Zhou , Hua Nan , Shao-Ming Fei , Zhi-Xi Wang

The uncertainty principle sets a bound on our ability to predict the measurement outcomes of two incompatible observables which are measured on a quantum particle simultaneously. In quantum information theory, the uncertainty principle can…

Quantum Physics · Physics 2019-12-03 H. Dolatkhah , S. Haseli , S. Salimi , A. s. Khorashad

A scheme is proposed to estimate the system and environmental parameter, the detuning, temperature and the squeezing strength with a high precision by the two-level atom system. It hasn't been reported that the squeezing strength estimation…

Quantum Physics · Physics 2021-05-07 Mengmeng Luo , Wenxiao Liu , Yuetao Chen , Shaoyan Gao

We identify the optimal measurement for obtaining information about the original quantum state after the state to be measured has undergone partial decoherence due to noise. We quantify the information that can be obtained by the…

Quantum Physics · Physics 2010-01-15 Yu Watanabe , Takahiro Sagawa , Masahito Ueda

Uncertainty relations give upper bounds on the accuracy by which the outcomes of two incompatible measurements can be predicted. While established uncertainty relations apply to cases where the predictions are based on purely classical data…

Quantum Physics · Physics 2012-10-18 Marco Tomamichel , Renato Renner

We show how to verify the metrological usefulness of quantum states based on the expectation values of an arbitrarily chosen set of observables. In particular, we estimate the quantum Fisher information as a figure of merit of metrological…

Quantum Physics · Physics 2017-04-25 Iagoba Apellaniz , Matthias Kleinmann , Otfried Gühne , Geza Toth

We highlight the advantages of using simultaneously the Shannon and Fisher information measures in providing a useful form of the uncertainty relation for the position-momentum case. It does not require any Fourier transformation. The…

Chemical Physics · Physics 2019-11-14 Kamal Bhattacharyya , Karabi Halder

The uncertainty principle can be understood as constraining the probability of winning a game in which Alice measures one of two conjugate observables, such as position or momentum, on a system provided by Bob, and he is to guess the…

Quantum Physics · Physics 2017-07-06 Joseph M. Renes