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Related papers: Uhlmann's theorem for measured divergences

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Quantum correlations are the singular, defining resource of quantum information science and metrology, forming the basis of every operational advantage that quantum systems hold over classical ones. Yet exact bounds on these…

Quantum Physics · Physics 2025-12-22 Samuel Alperin

We study the quantum fidelity (groundstate overlap) near quantum phase transitions of the Ising universality class in one dimensional (1D) systems of finite size L. Prominent examples occur in magnetic systems (e.g. spin-Peierls, the…

Mesoscale and Nanoscale Physics · Physics 2016-06-30 E. J. König , A. Levchenko , N. Sedlmayr

We provide a natural generalization of a Riemannian structure, i.e., a metric, recently introduced by Sj\"{o}qvist for the space of non degenerate density matrices, to the degenerate case, i.e., the case in which the eigenspaces have…

Quantum Physics · Physics 2021-02-22 Hector Silva , Bruno Mera , Nikola Paunković

Bregman divergences are a class of distance-like comparison functions which play fundamental roles in optimization, statistics, and information theory. One important property of Bregman divergences is that they cause two useful formulations…

Information Theory · Computer Science 2025-01-07 Philip S. Chodrow

Given an arbitrary quantum state ($\sigma$), we obtain an explicit construction of a state $\rho^*_\varepsilon(\sigma)$ (resp. $\rho_{*,\varepsilon}(\sigma)$) which has the maximum (resp. minimum) entropy among all states which lie in a…

Quantum Physics · Physics 2018-11-02 Eric P. Hanson , Nilanjana Datta

The existence of a unique Augustin mean and its invariance under the Augustin operator are established for arbitrary input distributions with finite Augustin information for channels with countably generated output $\sigma$-algebras. The…

Information Theory · Computer Science 2021-11-25 Hao-Chung Cheng , Baris Nakiboglu

We study fidelity susceptibility in one-dimensional asymmetric Hubbard model, and show that the fidelity susceptibility can be used to identify the universality class of the quantum phase transitions in this model. The critical exponents…

Quantum Physics · Physics 2009-11-13 Shi-Jian Gu , Ho-Man Kwok , Wen-Qiang Ning , Hai-Qing Lin

As a measure of the 'closeness' of two quantum states, fidelity plays a fundamental role in quantum information theory. Fidelity estimation protocols try to strike a balance between information gleaned from an experiment, and the efficiency…

In the problem of quantum state discrimination, one has to determine by measurements the state of a quantum system, based on the a priori side information that the true state is one of two given and completely known states, rho or sigma. In…

Quantum Physics · Physics 2012-12-11 Koenraad M. R. Audenaert , Milan Mosonyi , Frank Verstraete

We consider a fixed quantum measurement performed over $n$ identical copies of quantum states. Using a rigorous notion of distinguishability We consider a fixed quantum measurement performed over $n$ identical copies of quantum states.…

Quantum Physics · Physics 2007-05-23 Lev B. Levitin , Tommaso Toffoli , Zac D. Walton

Given two density matrices $\rho$ and $\sigma$, there are a number of different expressions that reduce to the $\alpha$-R\'enyi relative entropy of $\rho$ with respect to $\sigma$ in the classical case; i.e., when $\rho$ and $\sigma$…

Mathematical Physics · Physics 2018-11-14 Eric A. Carlen , Rupert L. Frank , Elliott H. Lieb

We study the convergence properties of state estimates of an oscillating qubit being monitored by a sequence of \textit{discrete}, unsharp measurements. Our method derives a differential equation determining the evolution of the estimation…

Quantum Physics · Physics 2017-05-31 Humairah Bassa , Lajos Diósi , Thomas Konrad , Hermann Uys

In this article, we study an opposite problem of universal quantum state comparison, that is unambiguous determining whether multiple unknown quantum states from a Hilbert space are orthogonal or not. We show that no unambiguous quantum…

Quantum Physics · Physics 2015-06-05 Shengshi Pang , Shengjun Wu

Fidelity plays an important role in quantum information theory. In this letter, we introduce new metric of quantum states induced by fidelity, and connect it with the well-known trace metric, Sine metric and Bures metric for the qubit case.…

Quantum Physics · Physics 2015-05-13 Zhihao Ma , Fu-Lin Zhang , Jing-Ling Chen

Various quantum analogues of the central limit theorem, which is one of the cornerstones of probability theory, are known in the literature. One such analogue, due to Cushen and Hudson, is of particular relevance for quantum optics. It…

Quantum Physics · Physics 2021-04-05 Simon Becker , Nilanjana Datta , Ludovico Lami , Cambyse Rouzé

A universal formulation of the quantum uncertainty regarding quantum indeterminacy, quantum measurement, and its inevitable observer effect is presented with additional focus on the representability of quantum observables over a given…

Quantum Physics · Physics 2022-04-27 Jaeha Lee

As an analogy of fully entangled fraction in the framework of entanglement theory, we have introduced the notion of quantum coherence fraction $C_{\mathcal{F}}$, which quantifies the closeness between a given state and the set of maximally…

Quantum Physics · Physics 2019-09-25 Yao Yao , Dong Li , C. P. Sun

R\'enyi divergence is related to R\'enyi entropy much like Kullback-Leibler divergence is related to Shannon's entropy, and comes up in many settings. It was introduced by R\'enyi as a measure of information that satisfies almost the same…

Information Theory · Computer Science 2014-04-25 Tim van Erven , Peter Harremoës

Robin's theorem is one of the ingenious reformulation of the Riemann hypothesis (RH). It states that the RH is true if and only if $\sigma(n)<e^\gamma n\log\log n$ for all $n>5040$ where $\sigma(n)$ is the sum of divisors of $n$ and…

Number Theory · Mathematics 2013-06-18 Sadegh Nazardonyavi , Semyon Yakubovich

Quantum Information Theory, the standard formalism used to represent information contained in quantum systems, is based on complex Hilbert spaces (CQT). It was recently shown that it predicts correlations in quantum networks which cannot be…

Quantum Physics · Physics 2025-03-14 Shubhayan Sarkar , David Trillo , Marc Olivier Renou , Remigiusz Augusiak