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Starting from a simple estimation problem, here we propose a general approach for decoding quantum measurements from the perspective of information extraction. By virtue of the estimation fidelity only, we provide surprisingly simple…

Quantum Physics · Physics 2022-10-04 Huangjun Zhu

Quantum optics bridges esoteric notions of entanglement and superposition with practical applications like metrology and communication. Throughout, there is an interplay between information theoretic concepts such as entropy and physical…

Quantum Physics · Physics 2025-01-07 Anaelle Hertz , Noah Lupu-Gladstein , Khabat Heshami , Aaron Z. Goldberg

A definition of quantum correlation is presented for an arbitrary bipartite quantum state based on the skew information. This definition not only inherits the good properties of skew information such as the contractivity and so on, but also…

Quantum Physics · Physics 2015-06-17 Chang-shui Yu , Shao-xiong Wu , Xiao-guang Wang , X. X. Yi , He-shan Song

Uncertainty relations and quantum entanglement are pivotal concepts in quantum theory. Beyond their fundamental significance in shaping our understanding of the quantum world, they also underpin crucial applications in quantum information…

Quantum Physics · Physics 2023-12-18 Yundu Zhao , Shan Huang , Shengjun Wu

We present an alternative definition of quantum entanglement for bipartite system based on Bell inequality and operators' noncommutativity. A state is said to be entangled, if the maximum of CHSH expectation value $F_{\max}$ is obtain by…

Quantum Physics · Physics 2007-05-23 Li-Bin Fu , Jing-Ling Chen , Xian-Geng Zhao , Shi-Gang Chen

We investigate how much information about a quantum system can be simultaneously communicated to independent observers, by establishing quantitative limits to bipartite quantum correlations in many-body systems. As recently reported in…

Quantum Physics · Physics 2024-02-09 Davide Girolami , Michele Minervini

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

The Measurement Based Quantum Computation (MBQC) model achieves universal quantum computation by employing projective single qubit measurements with classical feedforward on a highly entangled multipartite cluster state. Rapid advances in…

Quantum Physics · Physics 2021-12-23 Swapnil Nitin Shah

We prove three main conjectures of Berkovich and Uncu (Ann. Comb. 23 (2019) 263--284) on the inequalities between the numbers of partitions of $n$ with bounded gap between largest and smallest parts for sufficiently large $n$. Actually our…

Combinatorics · Mathematics 2020-04-29 Wenston J. T. Zang , Jiang Zeng

We settle the so-called degree conjecture for the separability of multipartite quantum states, which are normalized graph Laplacians, first given by Braunstein {\it et al.} [Phys. Rev. A \textbf{73}, 012320 (2006)]. The conjecture states…

Quantum Physics · Physics 2009-11-13 Ali Saif M. Hassan , Pramod Joag

An efficient method for assessing the quality of quantum state tomography is developed. Special attention is paid to the tomography of multipartite systems in terms of unbiased measurements. Although the overall reconstruction errors of…

Quantum Physics · Physics 2013-11-19 J. Rehacek , Z. Hradil , A. B. Klimov , G. Leuchs , L. L. Sanchez-Soto

We consider fundamental limits on the detectable size of macroscopic quantum superpositions. We argue that a full quantum mechanical treatment of system plus measurement device is required, and that a (classical) reference frame for phase…

Quantum Physics · Physics 2017-11-27 M. Skotiniotis , W. Dür , P. Sekatski

In his Comment [1], Philip Strasberg (PS) argues from the analysis of different examples that the framework we have presented in [2] does not recover known results of macroscopic textbook thermodynamics. Here, we show that such apparent…

Quantum Physics · Physics 2023-09-18 Cyril Elouard , Camille Lombard Latune

The notion of a macroscopic quantum state must be pinned down in order to assess how well experiments probe the large-scale limits of quantum mechanics. However, the issue of quantifying so-called quantum macroscopicity is fraught with…

Quantum Physics · Physics 2025-03-12 Benjamin Yadin , Matteo Fadel

We analyse two possible definitions of the squashed entanglement in an infinite-dimensional bipartite system: direct translation of the finite-dimensional definition and its universal extension. It is shown that the both definitions produce…

Quantum Physics · Physics 2016-10-07 M. E. Shirokov

We study the correlations of classical and quantum systems from the information theoretical points of view. We analyze a simple measure of correlations based on entropy (such measure was already investigated as the degree of entanglement by…

Quantum Physics · Physics 2012-09-13 Yuji Hirota , Dariusz Chruściński , Takashi Matsuoka , Masanori Ohya

We introduce a contextual quantum system comprising mutually complementary observables organized into two or more collections of pseudocontexts with the same probability sums of outcomes. These pseudocontexts constitute non-orthogonal bases…

Quantum Physics · Physics 2024-04-05 Mirko Navara , Karl Svozil

We investigate a two-qubit system to understand the relationship between concurrence and mutual information, where the former determines the amount of quantum entanglement, whereas the latter is its classical residue after performing local…

Quantum Physics · Physics 2022-10-05 Yong Kwon , Seung Ki Baek , Jaegon Um

The cross--product conjecture (CPC) of Brightwell, Felsner and Trotter (1995) is a two-parameter quadratic inequality for the number of linear extensions of a poset $P= (X, \prec)$ with given value differences on three distinct elements in…

Combinatorics · Mathematics 2022-12-05 Swee Hong Chan , Igor Pak , Greta Panova

General wisdom tells us that if two quantum states are ``macroscopically distinguishable'' then their superposition should be hard to observe. We make this intuition precise and general by quantifying the difficulty to observe the quantum…

Quantum Physics · Physics 2014-09-05 Pavel Sekatski , Nicolas Gisin , Nicolas Sangouard