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We present a model for an inhomogeneous and anisotropic early universe filled with a nonlinear electromagnetic field of Born-Infeld (BI) type. The effects of the BI field are compared with the linear case (Maxwell). Since the curvature…

General Relativity and Quantum Cosmology · Physics 2016-12-21 Ricardo Garcia-Salcedo , Nora Breton

We consider a magnetic Bianchi I braneworld, embedded in between two Schwarzschild-AdS spacetimes, boosted equal amounts in opposite directions and compare them to the analagous solution in four-dimensional General Relativity. The efficient…

High Energy Physics - Theory · Physics 2014-11-18 Gustavo Niz , Antonio Padilla , Hari K. Kunduri

For a cosmological Randall-Sundrum braneworld with anisotropy, i.e., of Bianchi type, the modified Einstein equations on the brane include components of the five-dimensional Weyl tensor for which there are no evolution equations on the…

High Energy Physics - Theory · Physics 2009-11-10 Antonio Campos , Roy Maartens , David Matravers , Carlos F. Sopuerta

The isotropy and homogeneity of our Universe are the cardinal principles of modern cosmology built on the definition of metric through the prescription by Friedmann-Lema$\hat{i}$tre-Robertson-Walker (FLRW). From the aspects of geometry, the…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-03 Jiwon Park , Sourav Mridha , Dukjae Jang , Mayukh R. Gangopadhyay , Myung-Ki Cheoun

The possible anisotropic nature in the early phases of the Universe is one of the interesting aspects of study in cosmology. We investigate the evolution of the Universe in terms of few cosmological parameters considering an anisotropic…

General Relativity and Quantum Cosmology · Physics 2023-04-03 Pranjal Sarmah , Avik De , Umananda Dev Goswami

The braneworld model of Dvali-Gabadadze-Porrati (DGP) provides an interesting alternative to a positive cosmological constant by modifying gravity at large distances. We investigate the asymptotic behavior of homogeneous and anisotropic…

General Relativity and Quantum Cosmology · Physics 2010-11-05 Tsutomu Kobayashi

We investigate brane-worlds with a pure magnetic field and a perfect fluid. We extend earlier work to brane-worlds, and find new properties of the Bianchi type I brane-world. We find new asymptotic behaviours on approach to the singularity…

General Relativity and Quantum Cosmology · Physics 2009-11-07 John D. Barrow , Sigbjorn Hervik

The observable universe is fundamentally inhomogeneous and anisotropic. Quantum description of the generation of these inhomogeneities and anisotropies is ill-understood and unsatisfactory. After providing a brief account of the standard…

General Relativity and Quantum Cosmology · Physics 2024-04-05 Sujoy K. Modak

The existence of stars and galaxies reqires cosmological models with an inhomogeneous matter and radiation distribution. But in these models the initial singularity surface t_0(r) is in general homogeneous (independent of r). In this second…

Astrophysics · Physics 2011-05-23 J. Schneider , M. N. Celerier

We study the behavior of spatially homogeneous brane-worlds close to the initial singularity in the presence of both local and nonlocal stresses. It is found that the singularity in these brane-worlds can be locally either isotropic or…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Alan A. Coley , Sigbjorn Hervik

We consider the cosmological evolution of a bulk scalar field and ordinary matter living on the brane world in the light of the constraints imposed by the matter dominated cosmological evolution and a small cosmological constant now. We…

High Energy Physics - Theory · Physics 2016-09-06 Ph. Brax , A. C. Davis

We reexamine Wald's no-hair theorem for global anisotropy in the brane world scenarios. We derive a set of sufficient conditions which must be satisfied by the brane matter and bulk metric so that a homogeneous and anisotropic brane…

High Energy Physics - Phenomenology · Physics 2009-11-07 M. G. Santos , F. Vernizzi , P. G. Ferreira

We consider the dynamics of a barotropic cosmological fluid in an anisotropic, Bianchi type I space-time in Eddington-inspired Born-Infeld (EiBI) gravity. By assuming an isotropic pressure distribution, we obtain the general solution of the…

General Relativity and Quantum Cosmology · Physics 2014-10-30 Tiberiu Harko , Francisco S. N. Lobo , M. K. Mak

Brane Gas Cosmology (BGC) is an approach to unifying string theory and cosmology in which matter is described by a gas of strings and branes in a dilaton gravity background. The Universe is assumed to start out with all spatial dimensions…

High Energy Physics - Theory · Physics 2009-11-07 Scott Watson , Robert H. Brandenberger

The standard cosmological model, based on general relativity with an inflationary era, is very effective in accounting for a broad range of observed features of the universe. However, the ongoing puzzles about the nature of dark matter and…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Roy Maartens

Homogeneous, nearly-isotropic Bianchi cosmological models are considered. Their time evolution is expressed as a complete set of non-interacting linear modes on top of a Friedmann-Robertson-Walker background model. This connects the…

General Relativity and Quantum Cosmology · Physics 2011-09-08 Andrew Pontzen , Anthony Challinor

A six dimensional standing-wave braneworld model has been constructed. It consists in an anisotropic 4-brane generated by standing gravitational waves whose source is normal matter. In this model the compact (on-brane) dimension is assumed…

High Energy Physics - Theory · Physics 2014-03-10 L. J. S. Sousa , W. T. Cruz , C. A. S. Almeida

It was found recently that the anisotropies in the homogeneous Bianchi I cosmology considered within the context of a specific Horndeski theory are damped near the initial singularity instead of being amplified. In this work we extend the…

General Relativity and Quantum Cosmology · Physics 2021-05-19 Rafkat Galeev , Ruslan Muharlyamov , Alexei A. Starobinsky , Sergey V. Sushkov , Mikhail S. Volkov

We discuss the problem of the stability of the isotropy of the universe in the space of ever-expanding spatially homogeneous universes with a compact spatial topology. The anisotropic modes which prevent isotropy being asymptotically stable…

General Relativity and Quantum Cosmology · Physics 2008-11-26 John D. Barrow , Hideo Kodama

We propose a cosmological model that describes isotropic expansion of inhomogeneous universe. The energy-momentum tensor that creates the spatial inhomogeneity may not affect the uniform expansion scaling factor $a(t)$ in the FLRW-like…

High Energy Physics - Theory · Physics 2014-10-15 Wei-Jian Geng , H. Lu