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We consider a FRW universe filled by a dark energy candidate together with other possible sources which may include the baryonic and non-baryonic matters. Thereinafter, we consider a situation in which the cosmos sectors do not interact…

General Relativity and Quantum Cosmology · Physics 2015-08-24 H. Ebadi , H. Moradpour

In this paper, at first, we focus on a FRW universe in which the dark energy candidate satisfies the Polytropic equation of state and study thermodynamics of dark energy. Bearing the thermal fluctuation theorem in mind, we establish a…

General Relativity and Quantum Cosmology · Physics 2016-06-07 H. Moradpour , M. T. Mohammadi Sabet

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

A new cosmic scenario with gravitationally induced particle creation is proposed. In this model the Universe evolves from an early to a late time de Sitter era, with the recent accelerating phase driven only by the negative creation…

General Relativity and Quantum Cosmology · Physics 2015-06-22 J. A. S. Lima , L. L. Graef , D. Pavón , S. Basilakos

Our Universe is expected to finally approach a de Sitter universe whose horizon is considered to be in thermal equilibrium. In the present article, both the energy stored on the horizon and its thermodynamic fluctuations are examined…

General Relativity and Quantum Cosmology · Physics 2022-02-25 Nobuyoshi Komatsu

Using Relativistic Quantum Geometry we study back-reaction effects of space-time inside the causal horizon of a static de Sitter metric, in order to make a quantum thermodynamical description of space-time. We found a finite number of…

General Relativity and Quantum Cosmology · Physics 2020-01-08 Juan Ignacio Musmarra , Mauricio Bellini

We have investigated the thermodynamical properties of the Universe with dark energy. Adopting the usual assumption in deriving the constant co-moving entropy density that the physical volume and the temperature are independent, we observed…

General Relativity and Quantum Cosmology · Physics 2010-10-27 Yungui Gong , Bin Wang , Anzhong Wang

By applying the unified first law of thermodynamics on the apparent horizon of FRW universe, we get the entropy relation for the apparent horizon in quasi-topological gravity theory. Throughout the paper, the results of considering the…

General Relativity and Quantum Cosmology · Physics 2016-05-17 H. Moradpour , R. Dehghani

In this paper, we point out thermodynamical description of ghost dark energy and its generalization to the early universe. Thereinafter, we find expressions for the entropy changes of these dark energy candidates. In addition, considering…

General Relativity and Quantum Cosmology · Physics 2015-05-06 M. Honarvaryan , A. Sheykhi , H. Moradpour

The thermodynamical properties of dark energy are usually investigated with the equation of state $\omega =\omega_{0}+\omega_{1}z$. Recent observations show that our universe is accelerating, and the apparent horizon and the event horizon…

Astrophysics · Physics 2008-11-26 Yongping Zhang , Ze-Long Yi , Tong-Jie Zhang , Wenbiao Liu

The de Sitter thermodynamics of cosmological models with a modified Friedmann equation is considered, with particular reference to high-energy Randall-Sundrum and Gauss-Bonnet braneworlds. The Friedmann equation can be regarded as the first…

High Energy Physics - Theory · Physics 2009-11-11 Gianluca Calcagni

This work continues the investigation in two recent papers on the quantum thermodynamics of spacetimes, 1) placing what was studied in [1] for thermal quantum fields in the context of early universe cosmology, and 2) extending the…

High Energy Physics - Theory · Physics 2024-11-26 Jen-Tsung Hsiang , Yu-Cun Xie , Bei-Lok Hu

We study evolution and thermodynamics of a slow-roll transition between early and late time de Sitter phases, both in the homogeneous case and in the presence of a black hole, in a scalar field model with a generic potential having both a…

High Energy Physics - Theory · Physics 2017-11-22 Ruth Gregory , David Kastor , Jennie Traschen

This thesis explores the thermodynamics of the cosmological horizon, aiming to make progress towards a better understanding of the microscopic nature of its entropy. We utilise the constrained nature of low-dimensional gravity to do so and…

High Energy Physics - Theory · Physics 2023-10-09 Eleanor Harris

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

A so-called "entropy-corrected holographic dark energy" (ECHDE), was recently proposed to explain the dark energy-dominated universe with the help of quantum corrections to the entropy-area relation in the setup of loop quantum cosmology.…

General Physics · Physics 2014-11-20 Mubasher Jamil , Ahmad Sheykhi , M. Umar Farooq

The thermodynamics of the Universe is restudied by requiring its compatibility with the holographic-style gravitational equations which govern the dynamics of both the cosmological apparent horizon and the entire Universe, and possible…

General Relativity and Quantum Cosmology · Physics 2015-07-29 David Wenjie Tian , Ivan Booth

The thermodynamic behavior of a decaying vacuum cosmology describing the entire cosmological history evolving between two extreme (early and late time) de Sitter eras is investigated. The thermal evolution from the early de Sitter to the…

General Relativity and Quantum Cosmology · Physics 2015-06-23 J. A. S. Lima , S. Basilakos , Joan Solà

In this note, we explore the thermodynamic properties of the universe in the background of the generalized energy-momentum-squared gravity. We derive the energy density of matter from the non-standard continuity equation and use it in our…

General Relativity and Quantum Cosmology · Physics 2021-06-23 Prabir Rudra , Behnam Pourhassan

We discuss the consequences of unique symmetry of de Sitter spacetime, which is invariant under the modified translations, ${\bf r}\rightarrow {\bf r} -e^{Ht}{\bf a}$, where $H$ is the Hubble parameter. Due to this symmetry, all the…

General Relativity and Quantum Cosmology · Physics 2024-06-25 G. E. Volovik
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