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In this work, we compute the universe temperature for the cosmological horizon for the FLRW metric. For this purpose, we consider a scalar field on the cosmological horizon. This scalar field satisfies the Klein-Gordon equation in a curved…

General Relativity and Quantum Cosmology · Physics 2024-05-15 Armando Meza Gaxiola , Pablo Padilla Longoria

In the current framework of Einstein's equations in general relativity (GR), gravity is described by the spacetime curvature. However, there are other descriptions where the origin of gravity can be understood through torsion and…

General Relativity and Quantum Cosmology · Physics 2022-12-02 Nakul Aggarwal , Ali Pourmand , Fatimah Shojai , Harish Parthasarathy

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

In the paper, we have presented a higher-dimensional cosmological model with a generalized Chaplygin-type gas to explain the recent acceleration of the universe. Dimensional reduction is feasible in this model, and our solutions are…

General Relativity and Quantum Cosmology · Physics 2025-07-01 D. Panigrahi , B. C. Paul , S. Chatterjee

In this paper we investigate the role played by dark energy in the form of Generalized cosmic Chaplygin gas in an accelerating universe described by FRW cosmology. We have tried to describe the model from the theoretical point of view of a…

General Relativity and Quantum Cosmology · Physics 2013-07-11 Prabir Rudra

We explore the late time cosmological dynamics of the Universe within the framework of $f(Q,\mathcal{L}_{m})$ gravity by considering the specific form $f(Q, \mathcal{L}_m)=-Q+2\mathcal{L}_m+\gamma$. To describe the cosmic pressure…

General Relativity and Quantum Cosmology · Physics 2025-08-08 Amit Samaddar , S. Surendra Singh

The Murchison Widefield Array (MWA) team has derived new upper limits on the spherically averaged power spectrum of the 21-cm signal at six redshifts in the range $z \approx 6.5-8.7$. We use these upper limits and a Bayesian inference…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-24 Raghunath Ghara , Sambit K. Giri , Benedetta Ciardi , Garrelt Mellema , Saleem Zaroubi

In this Letter, a modified Chaplygin gas (MCG) model of unifying dark energy and dark matter with the exotic equation of state $p_{MCG}=B\rho_{MCG} -\frac A{\rho_{MCG}^\alpha}$ is constrained from recently observed data: the 182 Gold SNe…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-07 Jianbo Lu , Lixin Xu , Jiechao Li , Baorong Chang , Yuanxing Gui , Hongya Liu

Redshift drift is the phenomenon whereby the observed redshift between an emitter and observer comoving with the Hubble flow in an expanding FLRW universe will slowly evolve -- on a timescale comparable to the Hubble time. In a previous…

General Relativity and Quantum Cosmology · Physics 2024-04-03 Francisco S. N. Lobo , José Pedro Mimoso , Jessica Santiago , Matt Visser

Observations of gamma-ray bursts up to $z\sim 9$ are best suited to study the possible evolution of the Universe equation of state at intermediate redshifts. We apply the Combo-relation to a sample of 174 gamma ray bursts to investigate…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-03 M. Muccino , L. Izzo , O. Luongo , K. Boshkayev , L. Amati , M. Della Valle , G. B. Pisani , E. Zaninoni

The idea of Verlinde that gravity is an entropic force caused by information changes associated with the positions of material bodies, is used in the present work for the FRW model of the Universe. Using modified Hawking temperature, the…

General Relativity and Quantum Cosmology · Physics 2016-10-31 Saugata Mitra , Subhajit Saha , Subenoy Chakraborty

Modified Chaplygin Gas has been successful in describing the cosmic history of the universe from radiation to $\Lambda$CDM in standard cosmology, while particle creation mechanism in nonlinear thermodynamics can be used to explain inflation…

General Relativity and Quantum Cosmology · Physics 2018-01-17 Subhra Bhattacharya , Shibaji Halder , Subenoy Chakraborty

The Cosmic Microwave Background radiation is a fundamental prediction of Hot Big Bang cosmology. The temperature of its black-body spectrum has been measured at the present time, $T_{\rm CMBR,0}$ = 2.726$\pm$ 0.010 K, and is predicted to…

Astrophysics · Physics 2016-03-23 R. Srianand , Patrick Petitjean , Cedric Ledoux

We study the cosmological scenario arising from the dynamics of a generalized Chaplygin gas. The equation of state of the system is given in terms of the energy density, $\rho$, and pressure, $p$, by the relationship $p = -…

Astrophysics · Physics 2007-05-23 M. C. Bento , O. Bertolami , A. A. Sen

We present a systematic characterization of the radio frequency (RF) spectra of homogeneous, paired atomic Fermi gases at finite temperatures, $T$, in the presence of final state interactions. The spectra, consisting of possible bound…

Superconductivity · Physics 2011-09-13 Yan He , Chih-Chun Chien , Qijin Chen , K. Levin

In the present work, we have made an attempt to investigate the dark energy possibility from the thermodynamical point of view. For this purpose, we have studied thermodynamic stability of three popular dark energy models in the framework…

General Relativity and Quantum Cosmology · Physics 2021-01-18 Abdulla Al Mamon , Pritikana Bhandari , Subenoy Chakraborty

We consider a model of the Universe with variable G and {\Lambda}. Subject of our interest is a phenomenological model for {\Lambda} proposed and considered in this article first time (up to our knowledge). Modification based on an…

General Relativity and Quantum Cosmology · Physics 2015-01-13 M. Khurshudyan , J. Sadeghi , E. Chubaryan , H. Farahani

In the present paper, we have investigated the Friedmann Robertson Walker (FRW) model in viable $f(R,T)$ gravity with $f(R,T)$ function proposed as $f(R,T)=R +\xi T^{1/2}$, where $\xi$ is an arbitrary constant, $R$ is the scalar curvature…

General Physics · Physics 2020-08-26 Nisha Godani , Gauranga C. Samanta

With considerations of the recently released WMAP year three and supernova legacy survey (SNLS) data set analysis that favors models similar to the $% \Lambda CDM$ model by possibly mild fluctuations around the vacuum energy or the…

Astrophysics · Physics 2007-05-23 Xin He Meng , Ming Guang Hu , Jie Ren

Constraining the dark energy deceleration parameter is one of the fascinating topics in the recent cosmological paradigm. This work aims to reconstruct the dark energy using parametrization of the deceleration parameter in a flat FRW…

General Relativity and Quantum Cosmology · Physics 2023-09-26 Amine Bouali , Himanshu Chaudhary , Ujjal Debnath , Alok Sardar , G. Mustafa