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Related papers: Variable $G$ Correction for Dark Energy Model in H…

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We study the consequences due to time varying $G$ and $\Lambda$ in scalar-tensor theories of gravity for cosmology, inspired by the modifications introduced by the Renormalization Group (RG) equations in the Quantum Einstein Gravity. We…

Astrophysics · Physics 2009-11-10 Claudio Rubano , Paolo Scudellaro

We review various modified gravities considered as gravitational alternative for dark energy. Specifically, we consider the versions of $f(R)$, $f(G)$ or $f(R,G)$ gravity, model with non-linear gravitational coupling or string-inspired…

High Energy Physics - Theory · Physics 2009-09-17 S. Nojiri , S. D. Odintsov

We review recent progress in the study of varying constants and attempts to explain the observed values of the fundamental physical constants. We describe the variation of $G$ in Newtonian and relativistic scalar-tensor gravity theories. We…

General Relativity and Quantum Cosmology · Physics 2009-09-25 John D. Barrow

The generalized Chaplygin gas (GCG) model allows for an unified description of the cosmologically recent accelerated expansion of the Universe and of the evolution of energy density perturbations. This dark energy - dark matter unification…

Astrophysics · Physics 2007-05-23 O. Bertolami

Statefinder diagnostic is a convenient method that can differentiate between the various dark energy models. In this article, we analyze the statefinder parameters in symmetric teleparallel cosmology. The $f(Q)$ gravity theory is an…

General Relativity and Quantum Cosmology · Physics 2022-06-27 Raja Solanki , P. K. Sahoo

In this work, we explore the impact of higher dimensional spacetime on the stellar structure and thermodynamic properties of neutron stars. Utilizing the density-dependent relativistic hadron field theory, we introduce modifications to…

General Relativity and Quantum Cosmology · Physics 2024-03-13 Debabrata Deb , Manjari Bagchi , Sarmistha Banik

We present a comprehensive investigation of cosmological constraints on the class of vector field formulations of modified gravity called Generalized Einstein-Aether models. Using linear perturbation theory we generate cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-25 J. Zuntz , T. G. Zlosnik , F. Bourliot , P. G. Ferreira , G. D. Starkman

We review the evidence for recently accelerating cosmological expansion or "dark energy", either a negative pressure constituent in General Relativity (Dark Energy) or modified gravity (Dark Gravity), without any Dark Energy constituent. If…

Astrophysics · Physics 2007-05-23 Sidney Bludman

In this paper, we intend to evaluate and analyze the statefinder parameters in $f(T)$ cosmology. Friedmann equation in $f(T)$ model is taken, and the statefinder parameters ${r,s}$ are calculated. We consider a model of $f(T)$ which…

General Physics · Physics 2012-11-13 Mubasher Jamil , Davood Momeni , Ratbay Myrzakulov , Prabir Rudra

In this paper, we study in Friedmann-Robertson-Walker universe the interaction between the viscous generalized Chaplygin gas with $f(R,T)$ gravity, which is an arbitrary function of the Ricci scalar $R$ and the trace $T$ of the…

General Relativity and Quantum Cosmology · Physics 2017-05-11 E. H. Baffou , I. G. Salako , M. J. S. Houndjo

We revisit the Kodama state by quantizing the theory of General Relativity (GR) with dynamical Chern-Simons (dCS) gravity. We find a new exact solution to the Wheeler-DeWitt equation where the Pontryagin term induces a modification in the…

High Energy Physics - Theory · Physics 2024-04-02 Stephon Alexander , Tatsuya Daniel , Joao Magueijo

Recently developed Generalized Cosmic Chaplygin gas (GCCG) is studied as an unified model of dark matter and dark energy. To explain the recent accelerating phase, the Universe is assumed to have a mixture of radiation and GCCG. The mixture…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Writambhara Chakraborty , Ujjal Debnath , Subenoy Chakraborty

We model the cosmic medium as the mixture of a generalized Chaplygin gas and a pressureless matter component. Within a neo-Newtonian approach we compute the matter power spectrum. The 2dFGRS data are used to discriminate between unified…

Astrophysics · Physics 2015-05-13 J. C. Fabris , S. V. B. Goncalves , H. E. S. Velten , W. Zimdahl

In this paper, after reconstructing the redshift evolution of the Hubble function by adopting Gaussian process techniques, we estimate the best-fit parameters for some flat Friedmann cosmological models based on a Modified Chaplygin Gas…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-28 Muhsin Aljaf , Daniele Gregoris , Martiros Khurshudyan

We investigate the generalized Quantum Chromodynamics (QCD) ghost model of dark energy in the framework of Einstein gravity. First, we study the non-interacting generalized ghost dark energy in a flat Friedmann-Robertson-Walker (FRW)…

General Relativity and Quantum Cosmology · Physics 2015-06-11 Esmaeil Ebrahimi , Ahmad Sheykhi , Hamzeh Alavirad

In this paper, we have studied $F(R,T)$ gravity as an arbitrary function of curvature and torsion scalars in Friedmann--Lema\^{\i}tre--Robertson--Walker (FLRW) background. Then, we have considered interacting model between $F(R,T)$ gravity…

General Relativity and Quantum Cosmology · Physics 2023-07-19 Ali R. Amani , S. L. Dehneshin

In this paper, we investigate the statefinder, the deceleration and equation of state parameters when universe is composed of generalized holographic dark energy or generalized Ricci dark energy for Bianchi I universe model. These…

General Relativity and Quantum Cosmology · Physics 2015-06-17 M. Sharif , Rabia Saleem

In this paper, we use Statefinder hierarchy method to distinguish between bimetric theory of massive gravity, galileon modified gravity and DGP models applied to late time expansion of the universe. We also carry out comparison between…

General Relativity and Quantum Cosmology · Physics 2013-10-28 R. Myrzakulov , M. Shahalam

I consider a scenario proposed by Fardon, Nelson and Weiner where dark energy and neutrinos are connected. As a result, neutrino masses are not constant but depend on the neutrino number density. By examining the full equation of state for…

High Energy Physics - Phenomenology · Physics 2009-11-10 R. D. Peccei

One of the central challenges in modern cosmology is understanding the nature of dark energy and its evolution throughout the history of the Universe. Dark energy is commonly modeled as a perfect fluid with a time-varying equation-of-state…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-26 Samsuzzaman Afroz , Suvodip Mukherjee
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