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Modern cosmology rests on the working assumption that the Universe is isotropic and homogeneous at large scales. Here, we document a number of anomalous observations pointing to an anisotropic Universe in a direction consistent with the CMB…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-22 Eoin Ó Colgáin

A cosmological scenario with two branes (A and B) moving in a 5-dimensional bulk is considered. As in the case of ecpyrotic and born-again braneworld models it is possible that the branes collide. The energy-momentum tensor is taken to…

General Relativity and Quantum Cosmology · Physics 2009-11-10 P. Kuusk , M. Saal

The singularity structure and the corresponding asymptotic behavior of a 3-brane coupled to a scalar field in a five dimensional bulk is analyzed in full generality, using the method of asymptotic splittings. It is shown that the collapse…

General Relativity and Quantum Cosmology · Physics 2010-04-21 Ignatios Antoniadis , Spiros Cotsakis , Ifigeneia Klaoudatou

In this work, the cosmological implications of brane world scenario are investigated when the gravitational coupling $G$ and the cosmological term $\Lambda$ are not constant but rather there are time variation of them. From observational…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Soma Nath , Subenoy Chakraborty , Ujjal Debnath

A brane universe moving in a curved higher dimensional bulk space is considered. The motion induces a cosmological evolution on the universe brane that is indistiguishable from a similar one induced by matter density on the brane. The…

High Energy Physics - Theory · Physics 2009-10-31 A. Kehagias , E. Kiritsis

I present the main features of the brane cosmology scenario, according to which our universe is a self-gravitating brane embedded in a five-dimensional spacetime.

Astrophysics · Physics 2007-05-23 David Langlois

We present a class of graviton-dilaton models in which a homogeneous isotropic universe, such as our observed one, evolves with no singularity at any time. Such models may stand on their own as interesting models for singularity free…

High Energy Physics - Theory · Physics 2009-10-30 S. Kalyana Rama

Usually, we assume that there is no inhomogeneity isotropic in terms of our location in our uni- verse. This assumption has not been observationally confirmed yet in sufficient accuracy, and we need to consider the possibility that there…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-06 Hiroyuki Negishi , Ken-ichi Nakao

In this work we would like to address the problem of the effect of bulk matter on the brane cosmological evolution in a general way. We assume that the spatial part of the brane metric is not maximally symmetric, therefore spatially…

General Relativity and Quantum Cosmology · Physics 2023-03-17 Pantelis S. Apostolopoulos

In brane-world cosmologies of Randall-Sundrum type, we show that evolution of large-scale curvature perturbations may be determined on the brane, without solving the bulk perturbation equations. The influence of the bulk gravitational field…

High Energy Physics - Theory · Physics 2009-10-09 David Langlois , Roy Maartens , Misao Sasaki , David Wands

The spatially homogeneous, isotropic Standard Cosmological Model appears to describe our Universe reasonably well. However, Einstein's equations allow a much larger class of cosmological solutions. Theorems originally due to Penrose and…

General Relativity and Quantum Cosmology · Physics 2007-05-23 B. K. Berger , D. Garfinkle , V. Moncrief

We consider ``cosmologically symmetric'' (i.e. solutions with homogeneity and isotropy along three spatial dimensions) five-dimensional spacetimes with a scalar field and a three-brane representing our universe. We write Einstein's…

High Energy Physics - Theory · Physics 2009-11-07 David Langlois , Maria Rodriguez-Martinez

A black universe is a nonsingular black hole where, beyond the horizon, there is an expanding, asymptotically isotropic universe. Such spherically symmetric configurations have been recently found as solutions to the Einstein equations with…

General Relativity and Quantum Cosmology · Physics 2010-03-19 K. A. Bronnikov , E. V. Donskoy

We consider the dynamics of a viscous cosmological fluid in the generalized Randall-Sundrum model for an anisotropic, Bianchi type I brane. To describe the dissipative effects we use the Israel-Hiscock-Stewart full causal thermodynamic…

General Relativity and Quantum Cosmology · Physics 2008-11-26 T. Harko , M. K. Mak

We obtain the entropy of a homogeneous anisotropic universe applicable, by assumption, to the fractional branes in the universe in the model of Chowdhury and Mathur. The entropy for the 3 or 4 charge fractional branes thus obtained is not…

High Energy Physics - Theory · Physics 2008-11-26 S. Kalyana Rama

We present a comprehensive study of the cosmological solutions of 6D braneworld models with azimuthal symmetry in the extra dimensions, moduli stabilization by flux or a bulk scalar field, and which contain at least one 3-brane that could…

High Energy Physics - Theory · Physics 2009-11-10 James M. Cline , Julie Descheneau , Massimo Giovannini , Jérémie Vinet

We point out several subtleties arising in brane-world scenarios of cosmological constant cancellation. We show that solutions with curvature singularities are inconsistent, unless the contribution to the effective four-dimentional…

High Energy Physics - Theory · Physics 2009-10-31 Stefan Forste , Zygmunt Lalak , Stéphane Lavignac , Hans Peter Nilles

We show that globally and regularly hyperbolic future geodesically incomplete isotropic universes, except for the standard all-encompassing `big crunch', can accommodate singularities of only one kind, namely, those having a non-integrable…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Spiros Cotsakis , Ifigeneia Klaoudatou

The global geometries of bulk vacuum space-times in the brane-universe models are investigated and classified in terms of geometrical invariants. The corresponding Carter-Penrose diagrams and embedding diagrams are constructed. It is shown…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Victor Berezin

We investigate cosmological consequences arising from the interaction between a homogeneous and isotropic brane-universe and the bulk. A Friedmann equation is derived which incorporates both the brane and bulk matter contributions, which…

High Energy Physics - Theory · Physics 2009-10-31 C. van de Bruck , M. Dorca , C. J. A. P. Martins , M. Parry