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We consider the gravitational model with additional spatial dimensions and anisotropic pressure which is nonzero only in these dimensions. Cosmological solutions in this model include accelerated expansion of the Universe at late age of its…

General Relativity and Quantum Cosmology · Physics 2014-02-19 O. A. Grigorieva , G. S. Sharov

Recent studies of Type Ia Supernovae with redshifts up to about $z~\laq~1$ reveal evidence for a cosmic acceleration in the expansion of the Universe. The most straightforward explanation to account for this acceleration is a cosmological…

General Relativity and Quantum Cosmology · Physics 2009-10-31 O. Bertolami , P. J. Martins

In this work we have investigated the possibility of having a late time accelerated phase of the universe, suggested by recent supernova observation, in the context of Brans Dicke (BD) theory with a symmetry breaking potential and a matter…

General Relativity and Quantum Cosmology · Physics 2009-10-31 S. Sen , A. A. Sen

Solutions to flat space Friedmann-Robertson-Walker cosmologies in Brans-Dicke theory with a cosmological constant are investigated. The matter is modelled as a $\gamma$-law perfect fluid. The field equations are reduced from fourth order to…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Shawn J. Kolitch

Analysing the Brans-Dicke solutions for the dust phase, we show that, for negative values of $\omega$, they contain scenarios that display an initial subluminal expansion followed by an inflationary phase. We discuss these solutions with…

General Relativity and Quantum Cosmology · Physics 2015-06-25 A. B. Batista , J. C. Fabris , R. de Sá Ribeiro

In this paper, spatially homogeneous and anisotropic Bianchi type-I cosmological models of Brans-Dicke theory of gravitation are investigated. The model represents accelerating universe at present and is considered to be dominated by dark…

General Physics · Physics 2021-08-02 Umesh Kumar Sharma , Gopi Kant Goswami , Anirudh Pradhan

We have investigated the possibility of having a late time accelerated expansion phase for the universe. We have used a dissipative fluid in Brans-Dicke(BD) theory for this purpose. The model does not involve any potential for the BD scalar…

General Relativity and Quantum Cosmology · Physics 2009-10-31 A. A. Sen , S. Sen , S. Sethi

We find a solution for exponential inflation in a Brans-Dicke generalized model, where the coupling "constant " is variable. While in General Relativity the equation of state is p is equal to minus rho, here we find p proportional to rho,…

General Relativity and Quantum Cosmology · Physics 2010-12-14 Marcelo S. Berman , Luis A. Trevisan

Nonlocal massive gravity can provide an interesting explanation for the late-time cosmic acceleration, with a dark energy equation of state $w_{\rm DE}$ smaller than $-1$ in the past. We derive the equations of linear cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-11 Savvas Nesseris , Shinji Tsujikawa

We analyze Brans-Dicke gravity with a cosmological constant, $\Lambda$, and cold dark matter (BD-$\Lambda$CDM for short) in the light of the latest cosmological observations on distant supernovae, Hubble rate measurements at different…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-25 Joan Sola , Adria Gomez-Valent , Javier de Cruz Perez , Cristian Moreno-Pulido

Three solutions of the Brans-Dicke theory with a self-interacting quartic potential and perfect fluid distribution are presented for a spatially flat geometry. The physical behavior is consistent with the recent cosmological scenario…

General Relativity and Quantum Cosmology · Physics 2009-11-07 M. K. Mak , T. Harko

In this paper, we study Friedmann cosmology with time-varying vacuum energy density in the context of Brans-Dicke theory. We consider an isotropic and homogeneous flat space, filled with a matter-dominated perfect fluid and a dynamical…

General Relativity and Quantum Cosmology · Physics 2024-01-09 C. P. Singh , Joan Sola Peracaula

The fact that the LambdaCDM model fits the observations does not necessarily imply the physical existence of `dark energy'. Dropping the assumption that cold dark matter (CDM) is a perfect fluid opens the possibility to fit the data without…

Astrophysics · Physics 2007-05-23 Dominik J. Schwarz

In this work we focus on a novel completion of the well-known Brans-Dicke theory that introduces an interaction between the dark energy and dark matter sectors, known as complete Brans-Dicke (CBD) theory. We obtain viable cosmological…

General Relativity and Quantum Cosmology · Physics 2017-10-10 Georgios Kofinas , Nelson A. Lima

The Brans-Dicke model with a variable cosmological term ($BD\Lambda$) has been investigated with use of the coupling constant of $\omega=10^4$. Parameters inherent in this model are constrained from comparison between Big Bang…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 E. P. B. A. Thushari , R. Nakamura , M. Hashimoto , K. Arai

The LCDM model has been presented with a number of cosmic tensions in the face of precision cosmological data, suggesting the presence of a dynamical dark energy component. In this context, we investigate the cosmology arising from a…

General Relativity and Quantum Cosmology · Physics 2026-05-08 Matthew Debono , Jackson Levi Said , Gabriel Farrugia

We revisit a model-independent estimator for cosmic acceleration based on type Ia supernovae distance measurements. This approach does not rely on any specific theory for gravity, energy content or parameterization for the scale factor or…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-02 Hermano Velten , Syrios Gomes , Vinicius C. Busti

Recently, few cosmological models with additional non-Riemannian volume form(s) have been proposed. In this article we use Supernovae type Ia experimental data to test one of these models which provides a unified description of both dark…

General Relativity and Quantum Cosmology · Physics 2018-10-05 Denitsa Staicova , Michail Stoilov

Brans-Dicke (BD) cosmology is reconsidered from an approach in which the model can be formulated in $\Lambda$CDM form, but at the expense of replacing the rigid cosmological constant $\Lambda$ with a dynamical quasivacuum component which…

General Relativity and Quantum Cosmology · Physics 2018-11-29 Javier de Cruz Perez , Joan Sola

We investigate to which extent a time variation of the gravitational constant or other fundamental constants affects the best fit of the Hubble diagram of type Ia supernovae. In particular, we show that a slow increase of $G$ in the past,…

Astrophysics · Physics 2007-05-23 Luca Amendola , Stefano Corasaniti , Franco Occhionero
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