{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,8]],"date-time":"2025-10-08T11:13:17Z","timestamp":1759921997874,"version":"build-2065373602"},"reference-count":74,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2025,1,16]],"date-time":"2025-01-16T00:00:00Z","timestamp":1736985600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"INFN via the Iniziativa Specifica GAST"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Universe"],"abstract":"<jats:p>This note aims to offer a non-technical and self-contained introduction to gravitational algebras and their applications in the nonequilibrium physics of gravitational systems. We begin by presenting foundational concepts from operator algebra theory and exploring their relevance to perturbative quantum gravity. Additionally, we provide a brief overview of the theory of nonequilibrium dynamical systems in finite dimensions and discuss its generalization to gravitational algebras. Specifically, we focus on entropy production in black hole backgrounds and fluctuation theorems in de Sitter spacetime.<\/jats:p>","DOI":"10.3390\/universe11010024","type":"journal-article","created":{"date-parts":[[2025,1,16]],"date-time":"2025-01-16T04:55:19Z","timestamp":1737003319000},"page":"24","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Gravitational Algebras and Applications to Nonequilibrium Physics"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9940-3250","authenticated-orcid":false,"given":"Michele","family":"Cirafici","sequence":"first","affiliation":[{"name":"Dipartimento di Matematica, Informatica e Geoscienze, Universit\u00e0 di Trieste, Via A. Valerio 12\/1, I-34127 Trieste, Italy"},{"name":"Institute for Geometry and Physics & INFN, Sezione di Trieste, 34136 Trieste, Italy"}]}],"member":"1968","published-online":{"date-parts":[[2025,1,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1007\/JHEP12(2019)063","article-title":"The entropy of bulk quantum fields and the entanglement wedge of an evaporating black hole","volume":"12","author":"Almheiri","year":"2019","journal-title":"J. High Energy Phys."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1007\/JHEP09(2020)002","article-title":"Entanglement Wedge Reconstruction and the Information Paradox","volume":"9","author":"Penington","year":"2020","journal-title":"J. High Energy Phys."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1007\/JHEP03(2022)205","article-title":"Replica wormholes and the black hole interior","volume":"3","author":"Penington","year":"2022","journal-title":"J. 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