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Within the framework of FRW cosmology, we study the QCD modified ghost scalar field models of dark energy in the presence of both interaction and viscosity. For a spatially non-flat FRW universe containing modified ghost dark energy (MGDE)…

General Physics · Physics 2013-04-30 K. Karami , S. Asadzadeh , M. Mousivand , Z. Safari

The effective field theory (EFT) of dark energy relies on three functions of time to describe the background dynamics. The viability of these functions is investigated here by means of a thorough dynamical analysis. While the system is…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Noemi Frusciante , Marco Raveri , Alessandra Silvestri

In this paper, we consider a recently proposed model of Dark Energy (DE) know as Modified Holographic Ricci DE (MHRDE) (which is function of the Hubble parameter and its first derivative with respect to the cosmic time $t$) in the light of…

General Physics · Physics 2017-05-31 Antonio Pasqua , Surajit Chattopadhyay , Iuliia Khomenko

We develop an efficient, non-parametric Bayesian method for reconstructing the time evolution of the dark energy equation of state w(z) from observational data. Of particular importance is the choice of prior, which must be chosen carefully…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Robert G. Crittenden , Gong-Bo Zhao , Levon Pogosian , Lado Samushia , Xinmin Zhang

Here, creation of the universe is obtained only from gravity sector. The dynamical universe begins with two basic ingredients (i) vacuum energy, also called dark energy (as vacuum energy is not observed) and (ii) background radiation. These…

High Energy Physics - Theory · Physics 2007-05-23 S. K. Srivastava

We present a geometrical approach that provides a non-perturbative technique, allowing the standard FLRW observer to evaluate a measurable, scale-dependent distance functional between her idealized FLRW past light cone and the actual…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-09 Mauro Carfora , Francesca Familiari

The effective evolution of an inhomogeneous universe model in any theory of gravitation may be described in terms of spatially averaged variables. In Einstein's theory, restricting attention to scalar variables, this evolution can be…

General Relativity and Quantum Cosmology · Physics 2010-04-06 Thomas Buchert

In the present research article, we have studied the flat FRW space time with domain wall and holographic dark energy in the context of $f(Q)$ theory of gravity. The exact solutions of the field equations are obtained using two different…

General Relativity and Quantum Cosmology · Physics 2024-10-11 S. P. Hatkar , D. P. Tadas , S. D. Katore

Using the first law of thermodynamics, we propose a relation between the system entropy ($S$) and its IR ($L$) and UV ($\Lambda$) cutoffs. In addition, applying this relation to the apparent horizon of flat FRW universe, whose entropy meets…

General Physics · Physics 2018-10-18 H. Moradpour , S. A. Moosavi , I. P. Lobo , J. P. Morais Graça , A. Jawad , I. G. Salako

We develop the reconstruction program for the number of modified gravities: scalar-tensor theory, $f(R)$, $F(G)$ and string-inspired, scalar-Gauss-Bonnet gravity. The known (classical) universe expansion history is used for the explicit and…

High Energy Physics - Theory · Physics 2010-04-06 Shin'ichi Nojiri , Sergei D. Odintsov

Recent data advances offer the exciting prospect of a first look at whether dark energy has a dynamical equation of state or not. While formally theories exist with a constant equation of state, they are nongeneric -- Einstein's…

Astrophysics · Physics 2009-11-10 Eric V. Linder , Ramon Miquel

We have studied the effect of dynamical radiation in the interacting barrow holographic dark energy model for a non-flat universe. For both open and closed universes, we have obtained the evolution equation for the energy density parameters…

General Relativity and Quantum Cosmology · Physics 2026-05-08 Gopinath Guin , Souvik Paul , Sunandan Gangopadhyay

Among different candidates to play the role of Dark Energy (DE), modified gravity has emerged as offering a possible unification of Dark Matter (DM) and DE. The purpose of this work is to develop a reconstruction scheme for the modified…

General Physics · Physics 2013-11-22 Surajit Chattopadhyay , Antonio Pasqua

We examine the dark energy and matter densities allowed by precision measurements of distances out to various redshifts, in the presence of spatial curvature and (near) arbitrary behavior of the dark energy equation of state. Degeneracies…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-22 Arman Shafieloo , Eric V. Linder

A system of effective Einstein equations for spatially averaged scalar variables of inhomogeneous cosmological models can be solved by providing a `cosmic equation of state'. Recent efforts to explain Dark Energy focus on `backreaction…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Thomas Buchert

In this paper, a general FRW cosmological model has been constructed in $f(R,T)$ gravity reconstruction with variable cosmological constant. A number of solutions to the field equations has been generated by utilizing a form for the Hubble…

General Relativity and Quantum Cosmology · Physics 2018-10-17 Nasr Ahmed , Sultan Z. Alamri

In this paper we undertake the modified theory of gravity f(R,T) where R and T are the Ricci scalar and the trace of the energy momentum tensor, respectively. Imposing the conservation of the energy momentum tensor, we obtain a model about…

General Relativity and Quantum Cosmology · Physics 2015-06-30 E. H. Baffou , A. V. Kpadonou , M. E. Rodrigues , M. J. S. Houndjo , J. Tossa

We apply a parametric reconstruction method to a homogeneous, isotropic and spatially flat Friedmann-Robertson-Walker (FRW) cosmological model filled of a fluid of dark energy (DE) with constant equation of state (EOS) parameter interacting…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Freddy Cueva Solano , Ulises Nucamendi

In this paper we study the impact of the fractional matter density uncertainty in the reconstruction of the equation of state of dark energy. We consider both standard reconstruction methods, based on the dynamical effect that dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-06 P. P. Avelino

We investigate the corresponding relation between $f(R)$ gravity and an interacting holographic dark energy. By obtaining conditions needed for some observational evidence such as, positive acceleration expansion of universe, crossing the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Kh. Saaidi , A. Aghamohammadi
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