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Related papers: Variable Equation of State for Generalized Dark En…

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In this paper, we have presented an accelerating cosmological model of the Universe in an extended symmetric teleparallel gravity or $f(Q,T)$ gravity. The parametric form of the Hubble parameter is, $H\left(z\right) =H_{0}\left[ \alpha…

General Relativity and Quantum Cosmology · Physics 2023-05-16 S. A. Narawade , M. Koussour , B. Mishra

The understanding of the accelerated expansion of the Universe poses one of the most fundamental questions in physics and cosmology today. Whether or not the acceleration is driven by some form of dark energy, and in the absence of a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 E. Piedipalumbo , E. Della Moglie , M. De Laurentis , P. Scudellaro

This research investigates the impact of modified gravity on cosmic scales, focusing on $f(Q)$ cosmology. By applying energy conditions, the study reconstructs various $f(Q)$ models, considering an accelerating Universe, quintessence, and a…

General Relativity and Quantum Cosmology · Physics 2025-04-14 Irfan Mahmood , Hira Sohail , Allah Ditta , S. H. Shekh , Anil Kumar Yadav

We Consider a cosmological model based on a generalization of the equation of state proposed by Nojiri and Odintsov [46] and \v{S}tefan\v{c}i'c [47], [48]. We argue that this model works as a dark fluid model which can interpolate between…

General Relativity and Quantum Cosmology · Physics 2023-02-17 Esraa Elkhateeb

Supernovae searches have shown that a simple matter-dominated and decelerating universe should be ruled out. However a determination of the present deceleration parameter $q_0$ through a simple kinematical description is not exempt of…

Astrophysics · Physics 2009-11-10 J. -M. Virey , P. Taxil , A. Tilquin , A. Ealet , C. Tao , D. Fouchez

We study non-viscous and viscous holographic dark energy models for a homogeneous and isotropic flat Friedmann-Robertson-Walker Universe in $f(R,T)$ gravity. We find that the Hubble horizon as an IR cut-off is suitable for both the models…

General Relativity and Quantum Cosmology · Physics 2015-10-15 C. P. Singh , Pankaj Kumar

The recent observations of type Ia supernovae suggest that the universe is accelerating now and decelerated in the recent past. This may be the evidence of the breakdown of the standard Friedmann equation. The Friedmann equation $H^2\sim…

Astrophysics · Physics 2009-09-29 Yungui Gong , Chang-Kui Duan

This work is motivated by the work of Kim et al (2008), which considered the equation of state parameter for the new agegraphic dark energy based on generalized uncertainty principle coexisting with dark matter without interaction. In this…

General Relativity and Quantum Cosmology · Physics 2012-02-21 Rahul Ghosh , Surajit Chattopadhyay , Ujjal Debnath

In this paper we present a generic form of the cosmological Equation of State derived from the formalism of Statistical Mechanics, assuming that a cosmic acceleration scenario can be interpreted as a system of quasi-particles. By…

General Relativity and Quantum Cosmology · Physics 2020-12-14 Elías Castellanos , Celia Escamilla-Rivera

We study the holographic dark energy model in a generalized scalar tensor theory. In a universe filled with cold dark matter and dark energy, the effect of potential of the scalar field is investigated in the equation of state parameter. We…

General Relativity and Quantum Cosmology · Physics 2009-02-18 Yousef Bisabr

The cosmological constant, which was introduced by Einstein a century ago to allow for a static universe, experienced a revival two decades ago under the label dark energy as a parameter to model the observed accelerated expansion of the…

General Physics · Physics 2019-01-08 Jan O. Stenflo

We investigate late time acceleration of the universe in higher dimensional cosmology. The content in the universe is assumed to exert pressure which is different in the normal and extra dimensions. Cosmologically viable solutions are found…

General Relativity and Quantum Cosmology · Physics 2011-09-29 Isha Pahwa , Debajyoti Choudhury , T. R. Seshadri

New dark energy models in anisotropic Bianchi type-I (B-I) space-time with variable EoS parameter and constant deceleration parameter have been investigated in the present paper. The Einstein's field equations have been solved by applying a…

General Physics · Physics 2011-07-15 Anirudh Pradhan , H. Amirhashchi , Bijan Saha

A generalized dynamical equation for the scale factor of the universe is proposed to describe the cosmological evolution, of which the $\Lambda$CDM model is a special case. It also provides a general example to show the equivalence of the…

Astrophysics · Physics 2009-11-11 J. Ren , X. H. Meng

The stable critical points and their corresponding cosmology are derived in the teleparallel gravity with an added Gauss-Bonnet topological invariant term. We have analyzed the dynamics of the Universe by presenting two cosmological viable…

General Relativity and Quantum Cosmology · Physics 2023-12-12 S. A. Kadam , Santosh V Lohakare , B. Mishra

We propose a parameterized equation of state for dark energy and perform observational tests with the Hubble parameter measurements, the Pantheon supernova sample, baryon acoustic oscillations, and DESI DR2 data. We obtain the best-fit…

General Relativity and Quantum Cosmology · Physics 2025-12-16 Jing-Ya Zhao , Tong-Yu He , Jia-Jun Yin , Zhan-Wen Han , Rong-Jia Yang

We present a dark fluid model which contains the general linear equation of state including the gravitation term. The obtained spherical symmetric Euler equation and the continuity equation was investigated with the Sedov-type…

General Relativity and Quantum Cosmology · Physics 2022-09-08 Imre F. Barna , Mihály A. Pocsai , Gergely Gábor Barnaföldi

We propose a novel parameterization of the dark energy density. It is particularly well suited to describe a non-negligible contribution of dark energy at early times and contains only three parameters, which are all physically meaningful:…

Astrophysics · Physics 2007-05-23 Michael Doran , Georg Robbers

The cosmological constant $\Lambda$ is a free parameter in Einstein's equations of gravity. We propose to fix its value with a boundary condition: test particles should be free when outside causal contact, e.g. at infinity. Under this…

General Physics · Physics 2019-05-24 Enrique Gaztanaga

In the present analysis, we explore a new version of dark energy called Barrow holographic dark energy within the framework modified gravity called $f(Q,T)$ gravity by adopting the simple homogeneous, isotropic, and spatially flat…

General Relativity and Quantum Cosmology · Physics 2024-08-09 N. Myrzakulov , S. H. Shekh , Anirudh Pradhan , K Ghaderi