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Related papers: Sequential measurements and entropy

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We derive a universal inequality that provides a lower bound on the ensemble-averaged von Neumann entropy change in a quantum system subject to continuous measurement and dissipation. Our result clarifies how entropy production is…

Quantum Physics · Physics 2025-06-17 Kohei Kobayashi

Classical and quantum information theory are simply explained. To be more specific it is clarified why Shannon entropy is used as measure of classical information and after a brief review of quantum mechanics it is possible to demonstrate…

Quantum Physics · Physics 2007-05-23 Nikolaos P. Papadakos

A general method for proving continuity of the von Neumann entropy on subsets of positive trace-class operators is considered. This makes it possible to re-derive the known conditions for continuity of the entropy in more general forms and…

Mathematical Physics · Physics 2015-05-13 M. E. Shirokov

We present a diffeomorphism-invariant formulation of differential entropy for Riemannian spaces, providing a fine-grained, coordinate-independent notion of quantum information for continuous variables in physical space. To this end, we…

Quantum Physics · Physics 2025-05-16 Pablo G. Camara

Jarzynski equality and related fluctuation theorems can be formulated for various setups. Such an equality was recently derived for nonunitary quantum evolutions described by unital quantum operations, i.e., for completely positive,…

Quantum Physics · Physics 2014-01-24 Alexey E. Rastegin , Karol Życzkowski

We derive a general information-theoretic equality for a system undergoing two projective measurements separated by a general temporal evolution. The equality implies the non-negativity of the mutual information between the measurement…

Quantum Physics · Physics 2015-06-04 Vlatko Vedral

Regarding the strange properties of quantum entropy and entanglement, e.g., the negative quantum conditional entropy, we revisited the foundations of quantum entropy, namely, von Neumann entropy, and raised the new method of quantum…

Quantum Physics · Physics 2012-05-08 Dong-Sheng Wang

We perform an information-theoretical analysis of quantum measurement processes and obtain the global information balance in quantum measurements, in the form of a closed chain equation for quantum mutual entropies. Our balance provides a…

Quantum Physics · Physics 2008-06-10 Francesco Buscemi , Masahito Hayashi , Michal Horodecki

The problem of estimating a parameter of a quantum system through a series of measurements performed sequentially on a quantum probe is analyzed in the general setting where the underlying statistics is explicitly non-i.i.d. We present a…

Quantum Physics · Physics 2015-12-01 Daniel Burgarth , Vittorio Giovannetti , Airi N. Kato , Kazuya Yuasa

A model of a quantum information source is proposed, based on the Gibbs ensemble of ideal (free) particles (bosons or fermions). We identify the (thermodynamic) von Neumann entropy as the information rate and establish the classical…

Mathematical Physics · Physics 2011-11-10 Oliver Johnson , Yuri Suhov

Historically, the element of uncertainty in quantum mechanics has been expressed through mathematical identities called uncertainty relations, a great many of which continue to be discovered. These relations use diverse measures to quantify…

Quantum Physics · Physics 2016-03-16 Varun Narasimhachar , Alireza Poostindouz , Gilad Gour

Some bounds on the entropic informational quantities related to a quantum continual measurement are obtained and the time dependencies of these quantities are studied.

Quantum Physics · Physics 2009-10-09 Alberto Barchielli , Giancarlo Lupieri

By considering the "kinetic-energy" term of the minimum principle for the Schr\"{o}dinger equation as a measure of information, that minimum principle is viewed as a statistical estimation procedure, analogous to the manner in which Jaynes…

Mathematical Physics · Physics 2007-05-23 John H. Van Drie

Quantum coherence and quantum correlations lie in the center of quantum information science, since they both are considered as fundamental reasons for significant features of quantum mechanics different from classical mechanics. We present…

Quantum Physics · Physics 2023-02-14 Zeyang Fan , Yi Peng , Yu-Ran Zhang , Shang Liu , Liang-Zhu Mu , Heng Fan

Projective measurement is a commonly used assumption in quantum mechanics. However, advances in quantum measurement techniques allow for partial measurements, which accurately estimate state information while keeping the wavefunction…

Quantum Physics · Physics 2021-08-24 Jonathan Monroe

Inspired by works on information transmission through quantum channels, we propose the use of a couple of mutual entropies to quantify the efficiency of continual measurement schemes in extracting information on the measured quantum system.…

Quantum Physics · Physics 2009-10-09 Albert Barchielli , Giancarlo Lupieri

Various measures have been suggested recently for quantifying the coherence of a quantum state with respect to a given basis. We first use two of these, the l_1-norm and relative entropy measures, to investigate tradeoffs between the…

Quantum Physics · Physics 2015-10-08 Shuming Cheng , Michael J. W. Hall

Phase-space features of the Wigner flow are examined so to provide a set of continuity equations that describe the flux of quantum information in the phase-space. The reported results suggest that the non-classicality profile of anharmonic…

Quantum Physics · Physics 2019-09-24 Alex E. Bernardini , Orfeu Bertolami

During a continuous measurement, quantum systems can be described by a stochastic Schr\"odinger equation which, in the appropriate limit, reproduces the von Neumann wave-function collapse. The average behavior on the ensemble of all…

Condensed Matter · Physics 2009-10-30 Carlo Presilla , Ubaldo Tanbini

We provide an introduction to the theory of quantum measurements that is centered on the pivotal role played by John von Neumann's model. This introduction is accessible to students and researchers from outside the field of foundations of…