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Finite tight frames are interesting in various topics including questions of quantum information. Each complex tight frame leads to a resolution of the identity in the Hilbert space. Symmetric informationally complete measurements are a…

Quantum Physics · Physics 2023-08-21 Alexey E. Rastegin

Measurement uncertainty relations are lower bounds on the errors of any approximate joint measurement of two or more quantum observables. The aim of this paper is to provide methods to compute optimal bounds of this type. The basic method…

Quantum Physics · Physics 2016-06-08 René Schwonnek , David Reeb , Reinhard F. Werner

Measurement outcomes of a quantum state can be genuinely random (unpredictable) according to the basic laws of quantum mechanics. The Heisenberg-Robertson uncertainty relation puts constrains on the accuracy of two noncommuting observables.…

Quantum Physics · Physics 2017-09-13 Xiao Yuan , Ge Bai , Tianyi Peng , Xiongfeng Ma

The uncertainty principle is one of the fundamental features of quantum mechanics and plays an essential role in quantum information theory. We study uncertainty relations based on variance for arbitrary finite $N$ quantum observables. We…

Quantum Physics · Physics 2023-03-30 Jing-Feng Wu , Qing-Hua Zhang , Shao-Ming Fei

Quantum physics constrains the accuracy of joint measurements of incompatible observables. Here we test tight measurement-uncertainty relations using single photons. We implement two independent, idealized uncertainty-estimation methods,…

By invoking quantum estimation theory we formulate bounds of errors in quantum measurement for arbitrary quantum states and observables in a finite-dimensional Hilbert space. We prove that the measurement errors of two observables satisfy…

Quantum Physics · Physics 2013-05-29 Yu Watanabe , Takahiro Sagawa , Masahito Ueda

In [Berta 2014 Entanglement], uncertainty relations in the presence of quantum memory was formulated for mutually unbiased bases using conditional collision entropy. In this paper, we generalize their results to the mutually unbiased…

Quantum Physics · Physics 2018-10-03 Kun Wang , Nan Wu , Fangmin Song

We formulate some properties of a set of several mutually unbiased measurements. These properties are used for deriving entropic uncertainty relations. Applications of mutually unbiased measurements in entanglement detection are also…

Quantum Physics · Physics 2015-05-07 Alexey E. Rastegin

The well-known Robertson-Schr\"odinger uncertainty relations have state-dependent lower bounds which are trivial for certain states. We present a general approach to deriving tight state-independent uncertainty relations for qubit…

Quantum Physics · Physics 2016-02-26 Alastair A. Abbott , Pierre-Louis Alzieu , Michael J. W. Hall , Cyril Branciard

We analyze the weak and critical points of various uncertainty relations that follow from the inequalities for the norms of vectors in the Hilbert space of states of a quantum system. There are studied uncertainty relations for sums of…

Quantum Physics · Physics 2025-08-13 Krzysztof Urbanowski

We derive uncertainty relation inequalities according to the mutually unbiased measurements. Based on the calculation of the index of coincidence of probability distribution given by $d+1$ MUMs on any density operator $\rho$ in…

Quantum Physics · Physics 2015-06-09 Bin Chen , Shao-Ming Fei

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

The uncertainty relation is a distinguishing feature of quantum theory, characterizing the incompatibility of noncommuting observables in the preparation of quantum states. Recently, many uncertainty relations were proposed with improved…

Quantum Physics · Physics 2017-12-25 Zhi-Xin Chen , Jun-Li Li , Qiu-Cheng Song , Hui Wang , S. M. Zangi , Cong-Feng Qiao

In standard formulations of the uncertainty principle, two fundamental features are typically cast as impossibility statements: two noncommuting observables cannot in general both be sharply defined (for the same state), nor can they be…

Quantum Physics · Physics 2018-06-08 Tom Bullock , Paul Busch

Majorization uncertainty relations are generalized for an arbitrary mixed quantum state $\rho$ of a finite size $N$. In particular, a lower bound for the sum of two entropies characterizing probability distributions corresponding to…

Quantum Physics · Physics 2018-04-17 Zbigniew Puchała , Łukasz Rudnicki , Aleksandra Krawiec , Karol Życzkowski

We study entropic uncertainty relations by using stepwise linear functions and quadratic functions. Two kinds of improved uncertainty lower bounds are constructed: the state-independent one based on the lower bound of Shannon entropy and…

Quantum Physics · Physics 2018-11-14 Zhihua Chen , Zhihao Ma , Yunlong Xiao , Shao-Ming Fei

The notion of mutual unbiasedness for coarse-grained measurements of quantum continuous variable systems is considered. It is shown that while the procedure of "standard" coarse graining breaks the mutual unbiasedness between conjugate…

Quantum Physics · Physics 2018-01-25 Daniel S. Tasca , Piero Sánchez , Stephen P. Walborn , Łukasz Rudnicki

The upper bound of the fine-grained uncertainty relation is different for classical physics, quantum physics and no-signaling theories with maximal nonlocality (supper quantum correlation), as was shown in the case of bipartite systems [J.…

Quantum Physics · Physics 2013-05-30 T. Pramanik , A. S. Majumdar

We analyze entropic uncertainty relations in a finite dimensional Hilbert space and derive several strong bounds for the sum of two entropies obtained in projective measurements with respect to any two orthogonal bases. We improve the…

Quantum Physics · Physics 2015-06-30 Łukasz Rudnicki , Zbigniew Puchała , Karol Życzkowski

In presence of quantum memory [M. Berta, M. Christandl, R. Colbeck, J.M. Renes, and R. Renner, Nature Phys. 6, 659 (2010)] the lower bound of entropic uncertainty relation depends on amount of entanglement between the particle (on which two…

Quantum Physics · Physics 2012-04-23 T. Pramanik , P. Chowdhury