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Related papers: Basics of observational entropy

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Entanglement entropy, which is a measure of quantum correlations between separate parts of a many-body system, has emerged recently as a fundamental quantity in broad areas of theoretical physics, from cosmology and field theory to…

Quantum Physics · Physics 2009-03-09 Israel Klich , Leonid Levitov

Statistical formulations of thermodynamic entropy, such as those by Boltzmann and Gibbs, were originally developed for classical systems and are well understood in that context. However, the foundational aspects of quantum statistical…

Quantum Physics · Physics 2025-10-08 Smitarani Mishra , Shaon Sahoo

Few parameters dependent generalised entropy includes Tsallis entropy, R{\'e}nyi entropy, Sharma-Mittal entropy, Barrow entropy, Kaniadakis entropy, etc as particular representatives. Its relation to physical systems is not always clear. In…

General Relativity and Quantum Cosmology · Physics 2023-08-16 Shin'ichi Nojiri , Sergei D. Odintsov

We review the plethora of uncertainty relations that appear in quantum mechanics and their nuances. We present both foundational applications, e.g. in understanding and defining complementarity, and practical applications, e.g. in quantum…

Quantum Physics · Physics 2026-04-13 Giovanni Chesi , Lorenzo Maccone

I give an informal overview of the decoherent histories approach to quantum mechanics, due to Griffiths, to Omn\`es, and to Gell-Mann and Hartle is given. Results on the connections between decoherence, records, correlation and entropy are…

General Relativity and Quantum Cosmology · Physics 2007-05-23 J. J. Halliwell

Quantum reference frames provide a relational description of multipartite quantum systems in which physical states and observables are defined relative to quantum observers. Yet different observers can assign different entropies to the same…

Quantum Physics · Physics 2026-03-26 Anne-Catherine de la Hamette

Why do we need quantization to describe vision? What are the quadrature operators of the electromagnetic field? Is it possible to measure them? What are the characteristic functions useful for? In this brief tutorial we provide the…

Quantum Physics · Physics 2021-10-08 Stefano Olivares

Projective measurement can increase the entropy of a state $\rho$, the increased entropy is not only up to the basis of projective measurement, but also has something to do with the properties of the state itself. In this paper we define…

Quantum Physics · Physics 2016-10-03 Xing Chen

We propose a formal framework for understanding and unifying the concept of observers across physics, computer science, philosophy, and related fields. Building on cybernetic feedback models, we introduce an operational definition of…

Quantum Physics · Physics 2026-01-08 Hatem Elshatlawy , Dean Rickles , Xerxes D. Arsiwalla

The principles of microscopic foundation of thermodynamics within the framework of relativistic quantum theory have been formulated

Statistical Mechanics · Physics 2025-09-30 A. Yu. Zakharov

We observe entropy decrease towards the past. Does this imply that in the past the world was in a non-generic microstate? I point out an alternative. The subsystem to which we belong interacts with the universe via a relatively small number…

History and Philosophy of Physics · Physics 2016-01-21 Carlo Rovelli

We improve the entropic uncertainty relations for position and momentum coarse-grained measurements. We derive the continuous, coarse-grained counterparts of the discrete uncertainty relations based on the concept of majorization. The…

Quantum Physics · Physics 2015-06-30 Łukasz Rudnicki

A colloquial interpretation of entropy is that it is the knowledge gained upon learning the outcome of a random experiment. Conditional entropy is then interpreted as the knowledge gained upon learning the outcome of one random experiment…

Quantum Physics · Physics 2024-11-20 Gilad Gour , Mark M. Wilde , Sarah Brandsen , Isabelle Jianing Geng

Multiscale systems are ubiquitous in science and technology, but are notoriously challenging to simulate as short spatiotemporal scales must be appropriately linked to emergent bulk physics. When expensive high-dimensional dynamical systems…

Machine Learning · Computer Science 2025-12-30 Quercus Hernandez , Max Win , Thomas C. O'Connor , Paulo E. Arratia , Nathaniel Trask

A microscopic understanding of the thermodynamic entropy in quantum systems has been a mystery ever since the invention of quantum mechanics. In classical physics, this entropy is believed to be the logarithm of the volume of phase space…

Quantum Physics · Physics 2013-05-08 J. M. Deutsch , Haibin Li , Auditya Sharma

Entropy is a fundamental concept in quantum information theory that allows to quantify entanglement and investigate its properties, for example its monogamy over multipartite systems. Here, we derive variational formulas for relative…

Quantum Physics · Physics 2024-05-21 Mario Berta , Marco Tomamichel

Recent advances in cooling, control, and measurement of mechanical systems in the quantum regime have opened the possibility of the first direct observation of quantum gravity, at scales achievable in experiments. This paper gives a broad…

Quantum Physics · Physics 2019-01-23 Daniel Carney , Philip C. E. Stamp , Jacob M. Taylor

Entropy is one of the key thermodynamic variables reflecting changes in the state of matter. Unlike other thermodynamic variables, it is well-defined also for nonequilibrium steady states through its relation to information. Applying this…

Statistical Mechanics · Physics 2026-04-15 Haim Diamant , Gil Ariel

Two very basic constructions involving experimental procedures are the formation of coarse-grained versions of experiments, and the formation of branching sequential experiments. The latter allow for the conditioning of states on the…

Quantum Physics · Physics 2024-10-14 Alex Wilce

The information on a quantum process acquired through measurements plays a crucial role in the determination of its non-equilibrium thermodynamic properties. We report on the experimental inference of the stochastic entropy production rate…