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Thermodynamics of extended gravity static spherically symmetric black hole solutions is investigated. The energy issue is discussed making use of the derivation of Clausius relation from equations of motion, evaluating the black hole…

General Relativity and Quantum Cosmology · Physics 2013-01-15 Guido Cognola , Lorenzo Sebastiani , Sergio Zerbini

Dealing with a generic time-local non-Markovian master equation, we define current and power to be process-dependent as in classical thermodynamics. Each process is characterized by a symmetry transformation, a gauge of the master equation,…

Quantum Physics · Physics 2023-08-01 Fernando Nicacio , Raphael N. P. Maia

We discuss black hole solutions of Einstein gravity in presence of nonlinear electrodynamics in dS spacetime. Considering prescribed entropy, thermodynamic volume of dS spacetime, We investigate properties of the effective thermodynamic…

High Energy Physics - Theory · Physics 2017-08-22 Hui-Hua Zhao , Li-Chun Zhang , Fang Liu , Ren Zhao

In this second part of our series of two papers, where spacetime is modelled by a graph, where Planck size quantum black holes lie on the vertices, we consider the thermodynamics of spacetime. We formulate an equation which tells in which…

General Relativity and Quantum Cosmology · Physics 2009-10-21 J. Makela

Scale-dependent gravity is an extension of general relativity in which the Newton and cosmological constants may vary slightly with the energy scale due to remnant low-energy quantum effects. A fundamental feature of this approach is the…

General Relativity and Quantum Cosmology · Physics 2026-02-03 Nicolas R. Bertini , Marcos H. Novaes

In this paper we continue the study of the physical consequences of our modified black hole entropy formula in expanding spacetimes. In particular, we apply the new formula to apparent horizons of Friedmann expanding universes with zero,…

High Energy Physics - Theory · Physics 2016-03-08 Stefano Viaggiu

We investigate an asymptotically spatially flat Robertson-Walker spacetime from two different perspectives. First, using von Neumann entropy, we evaluate the entanglement generation due to the encoded information in spacetime. Then, we work…

Quantum Physics · Physics 2017-06-21 Mehrnoosh Farahmand , Hosein Mohammadzadeh , Hossein Mehri-Dehnavi

A non-equilibrium picture of thermodynamics is discussed at the apparent horizon of FRW universe in $f(R,T)$ gravity, where $R$ is the Ricci scalar and $T$ is the trace of the energy-momentum tensor. We take two forms of the energy-momentum…

General Relativity and Quantum Cosmology · Physics 2015-06-04 M. Sharif , M. Zubair

There are problems with defining the thermodynamic limit of systems with long-range interactions; as a result, the thermodynamic behavior of these types of systems is anomalous. In the present work, we review some concepts from both…

Statistical Mechanics · Physics 2009-11-13 L. A. del Pino , P. Troncoso , S. Curilef

A celebrated result by Jacobson is the derivation of Einstein's equations from Unruh's temperature, the Bekenstein-Hawking entropy and the Clausius relation. This has been repeatedly taken as evidence for an interpretation of Einstein's…

General Relativity and Quantum Cosmology · Physics 2014-08-20 Goffredo Chirco , Hal M. Haggard , Aldo Riello , Carlo Rovelli

We study the thermodynamics and dynamics of high-dimensional Einstein-power-Yang-Mills black holes in conformal gravity. Specifically, we investigate a class of conformally related black holes whose metrics differ by a scale factor. We show…

General Relativity and Quantum Cosmology · Physics 2021-07-07 Yang Li , Yan-Gang Miao

The Friedmann equations of general relativity can be derived from the first law of thermodynamics when the entropy of the apparent horizon of a spatially isotropic universe is given by the Bekenstein-Hawking entropy. We point out that if…

General Relativity and Quantum Cosmology · Physics 2009-11-19 James E. Lidsey

We discuss the energy density,temperature and entropy of dark matter (DM) and dark energy (DE) as functions of the scale factor $a$ in an expanding universe. In a model of non-interacting dark components we repeat a derivation from…

General Relativity and Quantum Cosmology · Physics 2017-03-27 Z. Haba

Previously, the Einstein equation has been described as an equation of state, general relativity as the equilibrium state of gravity, and $f({\cal R})$ gravity as a non-equilibrium one. We apply Eckart's first order thermodynamics to the…

General Relativity and Quantum Cosmology · Physics 2021-06-09 Valerio Faraoni , Andrea Giusti

Inspired by the entropy-area relation of black hole thermodynamics, we study the thermodynamics of cosmological apparent horizon in a spatially flat Friedmann-Robertson-Walker (FRW) universe in the framework of an Extended Uncertainty…

General Relativity and Quantum Cosmology · Physics 2024-08-29 Maryam Roushan , Narges Rashidi , Kourosh Nozari

The linear response to temperature changes is derived for systems with overdamped stochastic dynamics. Holding both in transient and steady state conditions, the results allow to compute nonequilibrium thermal susceptibilities from…

Statistical Mechanics · Physics 2016-04-11 Gianmaria Falasco , Marco Baiesi

Viewing the cosmological constant $\Lambda<0$ as an independent variable, we consider the thermodynamics of the Schwarzschild black hole in an anti-de Sitter (AdS) background. For this system, there is one approach which regards the…

High Energy Physics - Theory · Physics 2018-10-17 José P. S. Lemos , Oleg B. Zaslavskii

At the level of the Planck scale, the spacetime metric has to be considered a quantum variable. Conformal quantum fluctuations of the metric tensor are studied here. They lead to an extra term in the Einstein equations which can be…

Astrophysics · Physics 2007-05-23 Alex H. Blin

The balance equations for thermodynamic quantities are derived from the nonlocal quantum kinetic equation. The nonlocal collisions lead to molecular contributions to the observables and currents. The corresponding correlated part of the…

Statistical Mechanics · Physics 2018-06-19 Klaus Morawetz

Based on the Newtonian mechanics, in this article, we present a heuristic derivation of the Friedmann equations, providing an intuitive foundation for these fundamental relations in cosmology. Additionally, using the first law of…

General Relativity and Quantum Cosmology · Physics 2024-12-31 Jaume de Haro , Emilio Elizalde , Supriya Pan