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Related papers: Saturating the quantum Cram\'er-Rao bound using LO…

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One key aspect of quantum metrology, measurement incompatibility, is evident only through the simultaneous estimation of multiple parameters. The symmetric logarithmic derivative Cram\'er-Rao bound (SLDCRB), gives the attainable precision,…

Quantum Physics · Physics 2024-09-26 Lorcán O. Conlon , Jun Suzuki , Ping Koy Lam , Syed M. Assad

The widely used quantum Cramer-Rao bound (QCRB) sets a lower bound for the mean square error of unbiased estimators in quantum parameter estimation, however, in general QCRB is only tight in the asymptotical limit. With a limited number of…

Quantum Physics · Physics 2016-09-07 Jing Liu , Haidong Yuan

Measurements that can be implemented via local operations and classical communication (LOCC) constitute a class of operations that is available in future quantum networks in which parties share entangled resource states. We characterise the…

Quantum Physics · Physics 2026-03-31 Arthur C. R. Dutra , Ties-A. Ohst , Hai-Chau Nguyen , Otfried Gühne

Generalized quantum measurements (also known as POVMs) are of great importance in quantum information and quantum foundations, but often difficult to perform. We present an experimental approach which can in principle be used to perform…

We experimentally demonstrate optomechanical motion and force measurements near the quantum precision limits set by the quantum Cram\'er-Rao bounds (QCRBs). Optical beams in coherent and phase-squeezed states are used to measure the motion…

We consider estimation of a single unknown parameter embedded in a quantum state. Quantum Cram\'er-Rao bound (QCRB) is the ultimate limit of the mean squared error for any unbiased estimator. While it can be achieved asymptotically for a…

Quantum Physics · Physics 2026-05-06 Zihao Gong , Boulat A. Bash

We consider an infinite class of unambiguous quantum state discrimination problems on multipartite systems, described by Hilbert space $\cal{H}$, of any number of parties. Restricting consideration to measurements that act only on…

Quantum Physics · Physics 2015-06-22 Scott M. Cohen

We explore the intersection of studies in quantum error correction and quantum local operations and classical communication (LOCC). We consider one-way LOCC measurement protocols as quantum channels and investigate their error correction…

Quantum Physics · Physics 2019-05-01 David Kribs , Comfort Mintah , Michael Nathanson , Rajesh Pereira

We provide rigorous, efficiently computable and tight bounds on the average error probability of multiple-copy discrimination between qubit mixed states by Local Operations assisted with Classical Communication (LOCC). In contrast to the…

Quantum Physics · Physics 2010-09-13 J. Calsamiglia , J. I. de Vicente , R. Munoz-Tapia , E. Bagan

We investigate strategies for reaching the ultimate limit on the precision of frequency estimation when the number of probes used in each run of the experiment is fixed. That limit is set by the quantum Cram\'er-Rao bound (QCRB), which…

Evaluating the amount of information obtained from non-orthogonal quantum states is an important topic in the field of quantum information. The commonly used evaluation method is Holevo bound, which only provides a loose upper bound for…

Quantum Physics · Physics 2021-09-27 Wei Li , Shengmei Zhao

Estimating correctly the quantum phase of a physical system is a central problem in quantum parameter estimation theory due to its wide range of applications from quantum metrology to cryptography. Ideally, the optimal quantum estimator is…

Quantum Physics · Physics 2021-06-09 Marco A. Rodríguez-García , Isaac Pérez Castillo , P. Barberis-Blostein

Estimation of parameters is a pivotal task throughout science and technology. Quantum Cram\'{e}r-Rao bound provides a fundamental limit of precision allowed to achieve under quantum theory. For closed quantum systems, it has been shown how…

Quantum Physics · Physics 2014-04-01 S. Alipour , M. Mehboudi , A. T. Rezakhani

Only with the simultaneous estimation of multiple parameters are the quantum aspects of metrology fully revealed. This is due to the incompatibility of observables. The fundamental bound for multi-parameter quantum estimation is the Holevo…

Quantum Physics · Physics 2019-11-20 Francesco Albarelli , Jamie F. Friel , Animesh Datta

It is a well-known fact that the optimal POVM for quantum state tomography is the symmetric, informationally complete, positive operator valued measure (SIC-POVM). We investigate the same problem only in the case when there are some a…

Quantum Physics · Physics 2015-11-23 Dénes Petz , László Ruppert

We consider the problem of estimating the state of a large but finite number $N$ of identical quantum systems. In the limit of large $N$ the problem simplifies. In particular the only relevant measure of the quality of the estimation is the…

Quantum Physics · Physics 2008-12-18 R. D. Gill , S. Massar

Randomness is a central feature of quantum mechanics and an invaluable resource for both classical and quantum technologies. Commonly, in Device-Independent and Semi-Device-Independent scenarios, randomness is certified using projective…

Quantum Physics · Physics 2022-11-08 Marco Avesani , Hamid Tebyanian , Paolo Villoresi , Giuseppe Vallone

Optimal measurements for quantum multiparameter estimation are complicated by the uncertainty principle. Generally, there is a trade-off between the precision with which different parameters can be simultaneously estimated. The task of…

Quantum Physics · Physics 2025-11-20 Simon K. Yung , C. M. Yung , Lorcán O. Conlon , Syed M. Assad

Measurement incompatibility is a cornerstone of quantum mechanics. In the context of estimating multiple parameters of a quantum system, this manifests as a fundamental trade-off between the precisions with which different parameters can be…

Quantum Physics · Physics 2025-11-11 Simon K. Yung , Aritra Das , Jun Suzuki , Ping Koy Lam , Jie Zhao , Lorcán O. Conlon , Syed M. Assad

Quantum state estimation is a fundamental task in quantum information theory, where one estimates real parameters continuously embedded in a family of quantum states. In the theory of quantum state estimation, the widely used Cram\'er Rao…

Quantum Physics · Physics 2025-07-23 Masahito Hayashi , Yingkai Ouyang