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We apply the first law of thermodynamics to the apparent horizon of the universe with the power-law corrected and non-extensive Tsallis entropies rather than the Bekenstein-Hawking one. We examine the cosmological properties in the two…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-14 Chao-Qiang Geng , Yan-Ting Hsu , Jhih-Rong Lu , Lu Yin

In this paper we have given a generalisation of the earlier work by Prigogine et al. who have constructed a phenomenological model of entropy production via particle creation in the very early universe generated out of the vacuum rather…

General Relativity and Quantum Cosmology · Physics 2015-06-05 G. K. Goswami , Mandwi Trivedi

The conception of gravity as an emergent phenomenon, rooted in the thermodynamics of spacetime, offers a radical departure from its geometric description. This paper investigates the emergence of cosmic space by synthesizing two key…

General Relativity and Quantum Cosmology · Physics 2026-01-05 Ahmad Sheykhi

Applying Clausius relation with energy-supply defined by the unified first law of thermodynamics formalism to the apparent horizon of a massive cosmological model proposed lately, the corrected entropic formula of the apparent horizon is…

General Relativity and Quantum Cosmology · Physics 2013-04-19 Hui Li , Yi Zhang

Cosmology is living through fascinating times, where new observations from ground and space telescopes are questioning the established paradigm, the so-called Lambda Cold Dark Matter model. The particle nature of Dark Matter is severely…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-15 Juan Garcia-Bellido

For two decades the hot big-bang model as been referred to as the standard cosmology -- and for good reason. For just as long cosmologists have known that there are fundamental questions that are not answered by the standard cosmology and…

Astrophysics · Physics 2009-10-31 Michael S. Turner

We apply the gravity-thermodynamics conjecture, namely the first law of thermodynamics on the Universe horizon, but using the generalized Kaniadakis entropy instead of the standard Bekenstein-Hawking one. The former is a one-parameter…

General Relativity and Quantum Cosmology · Physics 2021-12-07 Andreas Lymperis , Spyros Basilakos , Emmanuel N. Saridakis

Based on the conjecture that rather than the second law of thermodynamics inevitably be breached as matter approaches a big crunch or a black hole singularity, the order of events should reverse, a model of the universe that resolves a…

General Physics · Physics 2007-05-23 Peter Lynds

The notion of inflation (past or present) in standard cosmological models is shown to be a consequence of a sufficiently high second law entropy production from the internal heating of the universal expansion. The longitudinal viscous…

General Relativity and Quantum Cosmology · Physics 2007-05-23 T. Sakai , A. Widom , Y. N. Srivastava

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

In the Cadassian universe, one can explain the acceleration of the universe without introducing dark energy component. However, the dynamical equations of this model can not be directly obtained from the action principle. Recently, works on…

High Energy Physics - Theory · Physics 2011-07-08 Chao-Jun Feng , Xin-Zhou Li , Xian-Yong Shen

In a previous work (M. Campisi. Stud. Hist. Phil. M. P. 36 (2005) 275-290) we have addressed the mechanical foundations of equilibrium thermodynamics on the basis of the Generalized Helmholtz Theorem. It was found that the volume entropy…

Statistical Mechanics · Physics 2008-03-09 Michele Campisi

It is argued that the spatial homogeneity of the early universe need not be explained as having evolved from a previous inhomogeneous state. Rather, a homogeneous cosmic initial condition follows from the Second Law of Thermodynamics…

General Relativity and Quantum Cosmology · Physics 2018-06-21 Lucas Lolli Savi

In a quantum universe with a strong arrow of time, we postulate a low-entropy boundary condition (the Past Hypothesis) to account for the temporal asymmetry. In this paper, I show that the Past Hypothesis also contains enough information to…

Quantum Physics · Physics 2022-03-08 Eddy Keming Chen

Assuming that the background geometry is filled with free gas consisting of matter and radiation and no phase transitions being occurred in the early Universe, we discuss the thermodynamics of this {\it closed} system using classical…

General Relativity and Quantum Cosmology · Physics 2015-05-30 A. Tawfik , H. Magdy

In this letter we explore the foundations of entropic cosmology and highlight some important flaws which have emerged and adopted in the recent literature. We argue that, when applying entropy and temperature on the cosmological horizon by…

General Relativity and Quantum Cosmology · Physics 2024-03-25 Hussain Gohar , Vincenzo Salzano

Cosmology is nowadays going through a true revolution in the quantity and quality of observations that are capable of providing crucial information about the origin and evolution of the universe. In the first years of the next millenium we…

Astrophysics · Physics 2015-06-24 Juan Garcia-Bellido

This is a short summary of a project to construct a first principles cosmology of the Standard Model epoch, the period starting shortly before the electro-weak transition. The cosmology is derived from a simple initial state entirely within…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-14 Daniel Friedan

The standard model of cosmology is investigated using time dependent cosmological constant $\Lambda$ and Newton's gravitational constant $G$. The total energy content is described by the modified Chaplygin gas equation of state. It is found…

General Relativity and Quantum Cosmology · Physics 2009-03-12 Mubasher Jamil , Farook Rahaman , Mehedi Kalam

This article is a short version of a longer article to appear in Physics Reports (cond-mat/9708200). The essential postulates of classical thermodynamics are formulated, from which the second law is deduced as the principle of increase of…

Mathematical Physics · Physics 2007-05-23 Elliott H. Lieb , Jakob Yngvason