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The uncertainty principle restricts potential information one gains about physical properties of the measured particle. However, if the particle is prepared in entanglement with a quantum memory, the corresponding entropic uncertainty…

Quantum Physics · Physics 2017-03-10 Yunlong Xiao , Naihuan Jing , Xianqing Li-Jost

Uncertainty lower bounds for parameter estimations associated with a unitary family of mixed-state density matrices are obtained by embedding the space of density matrices in the Hilbert space of square-root density matrices. In the…

Quantum Physics · Physics 2021-10-20 Alex J. Belfield , Dorje C. Brody

Dynamics of coded information over Bloch channels is investigated for different values of the channel's parameters. We show that, the suppressing of the travelling coded information over Bloch channel can be increased by decreasing the…

Quantum Physics · Physics 2015-05-19 Nasser Metwally

Unambiguous unitary maps and unambiguous unitary quantum channels are introduced and some of their properties are derived. These properties ensure certain simple form for the measurements involved in realizing an unambiguous unitary quantum…

Quantum Physics · Physics 2008-11-14 Shengjun Wu , Xuemei Chen

This note explores uncertainty inequalities for quantum analogues of the Fisher information including the Wigner-Yanase skew information, and their connection to the quantum Sobolev inequalities proved by the author in [Journal of…

Mathematical Physics · Physics 2025-08-22 Laurent Lafleche

A concise review of various mathematical formulations of the uncertainty relations in quantum mechanics discovered since 1927 is given. Besides the traditional Heisenberg inequality, the modifications made by Schr\"odinger and Robertson, as…

Quantum Physics · Physics 2026-03-10 V. V. Dodonov

We show how the Schroedinger Uncertainty Relation for a pair of observables can be deduced using the Cauchy-Schwarz inequality plus successive applications of the commutation relation involving the two observables. Our derivation differs…

Physics Education · Physics 2015-08-26 Gustavo Rigolin

By preparing an input state and measuring an observable for the output state, we can measure a quantum channel. Following the formulation given by Xiao et al., we study an uncertainty relation for ancilla-free measurements of random unitary…

Quantum Physics · Physics 2023-03-22 Taihei Kimoto , Takayuki Miyadera

The sum of entropic uncertainties for the measurement of two non-commuting observables is not always reduced by the amount of entanglement (quantum memory) between two parties, and in certain cases may be impacted by quantum correlations…

Quantum Physics · Physics 2016-07-13 T. Pramanik , S. Mal , A. S. Majumdar

With the aid of a quantum memory, the uncertainty about the measurement outcomes of two incompatible observables of a quantum system can be reduced. We investigate this measurement uncertainty bound by considering an additional quantum…

Quantum Physics · Physics 2013-02-15 Ming-Liang Hu , Heng Fan

The measurement range problem, where one cannot determine the data outside the range of the detector, limits the characterization of entanglement in high-dimensional quantum systems when employing, among other tools from information theory,…

Quantum Physics · Physics 2019-02-01 J. Eli Bourassa , Hoi-Kwong Lo

This paper defines the squashed entanglement of a quantum channel as the maximum squashed entanglement that can be registered by a sender and receiver at the input and output of a quantum channel, respectively. A new subadditivity…

Quantum Physics · Physics 2014-07-16 Masahiro Takeoka , Saikat Guha , Mark M. Wilde

We study quantum information inequalities and show that the basic inequality between the quantum variance and the metric adjusted skew information generates all the multi-operator matrix inequalities or Robertson type determinant…

Mathematical Physics · Physics 2008-10-29 Koenraad Audenaert , Liang Cai , Frank Hansen

Uncertainty relations lie at the very core of quantum mechanics, and form the cornerstone of essentially all quantum cryptographic applications. In particular, they play an important role in cryptographic protocols in the…

Quantum Physics · Physics 2008-08-27 Stephanie Wehner , Andreas Winter

Entropic uncertainty relations play a fundamental role in quantum information theory. However, determining optimal (tight) entropic uncertainty relations for general observables remains a formidable challenge and has so far been achieved…

Quantum Physics · Physics 2026-02-03 Ma-Cheng Yang , Cong-Feng Qiao

It has been shown recently that the framework of quantum sampling, as introduced by Bouman and Fehr, can lead to new entropic uncertainty relations highly applicable to finite-key cryptographic analyses. Here we revisit these so-called…

Quantum Physics · Physics 2020-12-09 Keegan Yao , Walter O. Krawec , Jiadong Zhu

In the history of quantum mechanics, various types of uncertainty relationships have been introduced to accommodate different operational meanings of Heisenberg uncertainty principle. We derive an optimized entropic uncertainty relation…

Quantum Physics · Physics 2014-03-11 Kyunghyun Baek , Tristan Farrow , Wonmin Son

Uncertainty relations are fundamental in quantum mechanics. Here I propose state-independent variance-based uncertainty relations for two or more arbitrary observables in finite dimensional spaces. The uncertainty relations provide…

Quantum Physics · Physics 2021-07-28 Yichen Huang

We present a general refinement of the Cauchy-Schwarz inequality over complete inner product spaces and show that it can be of interest for some statistical applications. This generalizes and simplifies previous results on the same subject.

Statistics Theory · Mathematics 2024-04-10 Sergio Scarlatti

In this paper, we give a Schr\"odinger-type uncertainty relation using the Wigner-Yanase-Dyson skew information. In addition, we give Schr\"odinger-type uncertainty relation by use of a two-parameter extended correlation measure. Moreover,…

Quantum Physics · Physics 2012-01-17 Shigeru Furuichi , Kenjiro Yanagi