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The horizon of a flat Friedmann--Robertson--Walker (FRW) universe is considered to be dynamic when the Hubble parameter $H$ and the Hubble radius $r_{H}$ vary with time, unlike for de Sitter universes. To clarify the thermodynamics on a…

General Relativity and Quantum Cosmology · Physics 2023-10-17 Nobuyoshi Komatsu

The research work in the thesis is focused on the thermodynamic analysis of cosmological models, especially the models that explain late-time cosmic acceleration. According to the cosmological principle, the universe is spatially…

General Relativity and Quantum Cosmology · Physics 2024-06-05 Tanima Duary

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

A cosmological model based on holographic scenarios is formulated in a flat Friedmann-Robertson-Walker universe. To formulate this model, the cosmological horizon is assumed to have a general entropy and a general temperature (including…

General Relativity and Quantum Cosmology · Physics 2024-01-09 Nobuyoshi Komatsu

We assume the non-flat Friedmann-Robertson-Walker (FRW) Universe as a thermodynamical system. We assume the cosmological horizon as a inner trapping horizon which is treated as dynamical apparent horizon of FRW Universe. We write the…

General Relativity and Quantum Cosmology · Physics 2020-10-06 Ujjal Debnath

This work considers how exponential corrections to the Bekenstein-Hawking entropy formula affect the thermodynamic behavior of the FLRW cosmological model. These corrections drastically change the form of the Friedman field equations…

High Energy Physics - Theory · Physics 2025-11-25 Rodrigo Rivadeneira-Caro , Joel F. Saavedra , Francisco Tello-Ortiz

The first and second laws of thermodynamics should lead to a consistent scenario for discussing the cosmological constant problem. In the present study, to establish such a thermodynamic scenario, cosmological equations in a flat…

General Relativity and Quantum Cosmology · Physics 2025-06-05 Nobuyoshi Komatsu

Entropic-force cosmology provides, in contrast with dark energy descriptions, a concrete physical understanding of the accelerated expansion of the universe. The acceleration appears to be a consequence of the entropy associated with the…

General Relativity and Quantum Cosmology · Physics 2022-08-15 D. J. Zamora , C. Tsallis

The thermodynamic properties of loop quantum cosmology (LQC) without considering the Lorentz term were established in \cite{Zhu09}. In this paper, we extend this result to the recent proposed new model of LQC with the Lorentz term. We…

General Relativity and Quantum Cosmology · Physics 2021-11-11 Xiangdong Zhang

In this work, we study some thermodynamical aspects associated with torsion in a flat FLRW spacetime cosmic evolution. By implementing two Ansatze for the torsion term, we find that the model admits a phantom regime or a quintessence…

General Relativity and Quantum Cosmology · Physics 2020-06-26 Miguel Cruz , Fernando Izaurieta , Samuel Lepe

We derive non-flat cosmological models for two cases (i.e., dust and radiation) in the context of M{\o}ller's tetradic theory (MTT) of gravitation using the tetrad that creates the non-flat Friedmann-Robertson-Walker (FRW) metric. These two…

General Relativity and Quantum Cosmology · Physics 2022-04-21 G. G. L. Nashed , A. T. Shafeek

In `entropic cosmology', instead of a cosmological constant $\Lambda$, an extra driving term is added to the Friedmann equation and the acceleration equation, taking into account the entropy and the temperature on the horizon of the…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-14 Nobuyoshi Komatsu , Shigeo Kimura

We establish a general thermodynamic scheme for cosmic fluids with internal self-interactions and discuss equilibrium and non-equilibrium aspects of such systems in connection with (generalized) symmetry properties of the cosmological…

Astrophysics · Physics 2009-10-31 Winfried Zimdahl , Alexander B. Balakin

The thermal history of a large class of running vacuum models in which the effective cosmological term is described by a truncated power series of the Hubble rate, whose dominant term is $\Lambda (H) \propto H^{n+2}$, is discussed in…

General Relativity and Quantum Cosmology · Physics 2016-04-29 J. A. S. Lima , Spyros Basilakos , Joan Solà

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

This paper deals with gravitational thermodynamics on the dynamical apparent horizon of an FLRW universe with dissipation. The dissipation is assumed to arise due to adiabatic gravitational particle creation. For the thermodynamic study, we…

General Relativity and Quantum Cosmology · Physics 2025-02-24 Somnath Saha , Subhajit Saha , Nilanjana Mahata

This work investigates the dynamical evolution of the universe within the framework of symmetric teleparallel $f(Q,\mathcal{T})$ gravity, where $Q$ is the non-metricity scalar and $\mathcal{T}$ is the trace of the energy-momentum tensor. We…

General Relativity and Quantum Cosmology · Physics 2026-05-19 S. H. Shekh , S. B. Thool , Pankaj Kumar , P. C. Kalan , R. M. Dhaigude

In the context of thermodynamics applied to our cosmological apparent horizon, we explicit in greater details our previous work which established the Friedmann Equations from projection of Hayward's Unified First Law. In particular, we show…

General Relativity and Quantum Cosmology · Physics 2015-02-17 Alexis Helou

To investigate the relationship between gravity and thermodynamics in the case of dynamic systems, we interpret the apparent horizon of the Friedmann-Lema\^itre-Robertson-Walker (FLRW) spacetime as a thermodynamic system. We derive the…

General Relativity and Quantum Cosmology · Physics 2023-03-22 Luis M. Sanchez , Hernando Quevedo

In this paper, a general entropy-corrected FRW cosmological model has been presented in which a deceleration-to-acceleration transition occurs according to recent observations. We found that the case for the flat universe ($k=0$), supported…

General Relativity and Quantum Cosmology · Physics 2019-10-23 Nasr Ahmed , Sultan Z. Alamri
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