English
Related papers

Related papers: Phenomenological modification of horizon temperatu…

200 papers

Thermodynamics on the horizon of a flat universe at late times is studied in holographic cosmological models that assume an associated entropy on the horizon. In such models, a $\Lambda(t)$ model similar to a time-varying $\Lambda(t)$…

General Relativity and Quantum Cosmology · Physics 2020-01-01 Nobuyoshi Komatsu

The Friedmann equation in the Friedmann-Robertson-Walker(FRW) universe with any spatial curvature is derived from the first law of thermodynamics on the event horizon. The key idea is to redefine a Hawking temperature on the event horizon.…

High Energy Physics - Theory · Physics 2016-03-08 Fei-Quan Tu , Yi-Xin Chen

The paper deals with universal thermodynamics for FRW model of the universe bounded by apparent (or event) horizon. Assuming Hawking temperature on the horizon, the unified first law is examined on the horizon for different gravity…

General Relativity and Quantum Cosmology · Physics 2016-05-17 Saugata Mitra , Subhajit Saha , Subenoy Chakraborty

A phenomenological approach is proposed to the problem of universe accelerated expansion and of the dark energy nature. A general class of models is introduced whose energy density depends on the redshift $z$ in such a way that a smooth…

Astrophysics · Physics 2009-11-10 V. F. Cardone , A. Troisi , S. Capozziello

Starting from the first law of thermodynamics, $dE=T_hdS_h+WdV$, at apparent horizon of a FRW universe, and assuming that the associated entropy with apparent horizon has a quantum corrected relation, $S=\frac{A}{4G}-\alpha \ln…

High Energy Physics - Theory · Physics 2011-02-09 Ahmad Sheykhi

We study the effects of quantum fluctuations on the event horizon area and their implications for corrections to the Bekenstein-Hawking entropy. These quantum corrections are incorporated into the framework of large-scale gravitational…

High Energy Physics - Theory · Physics 2025-01-08 Alireza Maleki , Ahmad Sheykhi

Starting from the Modified Newtonian Dynamics (MOND) theory and using an inverse approach, we construct a general form of the entropy expression associated with the horizon based on the entropic nature of gravity. Using the…

General Physics · Physics 2025-10-17 Ahamd Sheykhi , Leila Liravi

We point out that, due to the nonlinearity of the Einstein equations, a homogeneous approximation in cosmology leads to the appearance of an additional term in the Friedmann equation. This new term is associated with the spatial…

Astrophysics · Physics 2015-06-24 Gyula Bene , Viktor Czinner , Matyas Vasuth

In this work, we explore the effect at cosmological level of the extra contribution arising from the Geodetic Brane Gravity model within a thermodynamical perspective. As already known, the universe seen as an extended object embedded…

High Energy Physics - Theory · Physics 2026-01-27 Gilberto Aguilar-Pérez , Giovany Cruz , Miguel Cruz , Efraín Rojas

We investigate the laws of thermodynamics in an accelerating universe driven by dark energy with a time-dependent equation of state. In the case we consider that the physically relevant part of the Universe is that envelopped by the…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Bin Wang , Yungui Gong , Elcio Abdalla

In this paper, we study thermodynamical properties of the apparent horizon in a universe governed by quasi-topological gravity. Our aim is twofold. First, by using the variational method we derive the general form of Friedmann equation in…

High Energy Physics - Theory · Physics 2015-06-16 M. H. Dehghani , A. Sheykhi , R. Dehghani

This paper is the second of two papers devoted to the study of the evolution of the cosmological horizons (particle and event horizons). Specifically, in this paper we consider the extremely general case of an accelerated universe with…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-28 Berta Margalef-Bentabol , Juan Margalef-Bentabol , Jordi Cepa

We use numerical relativity to study the violent preheating era at the end of inflation. This epoch can result in highly nonlinear fluctuations in density and gravitational potential which feed back onto the averaged expansion rate -- an…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-15 Ryn Grutkoski , Hayley J. Macpherson , John T. Giblin , Joshua Frieman

A common feature in the thermodynamic analysis of homogeneous and isotropic world models is the assumption that the temperature of the fluids inside the cosmic horizon (including dark energy) coincides with the temperature of the latter,…

General Relativity and Quantum Cosmology · Physics 2016-11-18 José Pedro Mimoso , Diego Pavón

In a recent article we have introduced Friedmann thermodynamics, where certain geometric parameters in Friedmann models are treated like their thermodynamic counterparts (temperature, entropy, Gibbs potential etc.). This model has the…

General Relativity and Quantum Cosmology · Physics 2008-04-02 Selcuk S. Bayin

In this work, we derive a generalized modified Friedmann equation based on an entropy-area relation that incorporates established modifications, such as volumetric, linear, and logarithmic terms, in addition to novel entropic modifications…

General Relativity and Quantum Cosmology · Physics 2024-12-17 Javier Chagoya , I. Díaz-Saldaña , Mario H. Amante , J. C. López-Domínguez , M. Sabido

In this work we apply the gravity-thermodynamics approach for the case of generalized mass-to-horizon entropy, which is a two-parameter extension of Bekenstein-Hawking entropy that arises from the extended mass-to-horizon relation, that is…

General Relativity and Quantum Cosmology · Physics 2025-04-01 Spyros Basilakos , Andreas Lymperis , Maria Petronikolou , Emmanuel N. Saridakis

We investigate the thermodynamic and phenomenological implications of a cosmological model governed by fractional entropy applied to the apparent horizon of a flat Friedmann-Lema\^{i}tre-Robertson-Walker (FLRW) universe. By utilizing the…

General Relativity and Quantum Cosmology · Physics 2026-04-21 Miguel Cruz , Diego da Silva , Simón González , Samuel Lepe , Joel Saavedra , Manuel Gonzalez-Espinoza

An alternative to dark energy as an explanation for the present phase of accelerated expansion of the Universe is that the Friedmann equation is modified, e.g. by extra dimensional gravity, on large scales. We explore a natural…

Astrophysics · Physics 2009-11-10 Oystein Elgaroy , Tuomas Multamaki

Assuming that an accelerated observer with four-velocity ${\bf u}_{\rm R}$ in a curved spacetime attributes the standard Bekenstein-Hawking entropy and Unruh temperature to his "local Rindler horizon", we show that the $\rm \it change$ in…

General Relativity and Quantum Cosmology · Physics 2016-06-21 Dawood Kothawala