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While most of the singularities of General Relativity are expected to be safely hidden behind event horizons by the cosmic censorship conjecture, we happen to live in the causal future of the classical big bang singularity, whose resolution…

High Energy Physics - Theory · Physics 2015-06-17 Razieh Pourhasan , Niayesh Afshordi , Robert B. Mann

We consider brane-world models embedded in a five-dimensional bulk spacetime with a large extra dimension and a cosmological constant. The cosmology in $5D$ possesses "wave-like" character in the sense that the metric coefficients in the…

General Relativity and Quantum Cosmology · Physics 2010-01-27 J. Ponce de Leon

We consider the possibility of getting accelerated expansion and w=-1 crossing in the context of a braneworld cosmological setup, endowed with a bulk energy-momentum tensor. For a given ansatz of the bulk content, we demonstrate that the…

High Energy Physics - Theory · Physics 2008-11-26 C. Bogdanos , A. Dimitriadis , K. Tamvakis

In a thermodynamical model of cosmological FLRW event horizons for the dark energy (DE), we consider a logarithmic corrective term in the entropy to which corresponds a new term in the DE density. This model of $\Lambda (t)$ in an…

Astrophysics · Physics 2016-08-15 Cécile Barbachoux , Jérome Gariel , Gérard Le Denmat

Much work has been devoted to the phenomenology and cosmology of the so-called braneworld universe, where our (3+1)-dimensional universe lies on a brane surrounded by a (4+1)-dimensional bulk spacetime that is essentially empty except for a…

High Energy Physics - Theory · Physics 2009-11-07 Martin Bucher

Modifications to the Friedmann equation in brane cosmology can have important implications for early universe phenomena such as inflation and the generation of the baryon asymmetry. In the framework of braneworld cosmology, we discuss a…

High Energy Physics - Phenomenology · Physics 2017-08-23 N. M. C. Santos , M. C. Bento , R. González Felipe

We discuss how Starobinsky-like inflation may emerge from dilaton dynamics in brane cosmology scenarios based on string theory, in which our universe is represented as a three-brane. The effective potential may acquire a constant term from…

High Energy Physics - Theory · Physics 2015-06-18 John Ellis , Nick E. Mavromatos , Dimitri V. Nanopoulos

Exact global solutions of five-dimensional cosmological models compactified on a $S_1/Z_2$ orbifold with two 3-branes are presented, and evolution of a simple model is studied. It is found that on all 4D spacetime hypersurfaces, except a…

High Energy Physics - Theory · Physics 2014-11-18 Hongya Liu

In the context of brane cosmology, a scenario where our universe is a 3+1-dimensional surface (the ``brane'') embedded in a five-dimensional spacetime (the ``bulk''), we study geometries for which the brane is anisotropic - more…

High Energy Physics - Theory · Physics 2010-02-03 A. Fabbri , D. Langlois , D. A. Steer , R. Zegers

We present the four-dimensional equations on a brane with a scalar field non-minimally coupled to the induced Ricci curvature, embedded in a five-dimensional bulk with a cosmological constant. This is a natural extension to a brane-world…

High Energy Physics - Theory · Physics 2009-11-10 Mariam Bouhmadi-Lopez , David Wands

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

Loop quantum cosmology homogeneous models with a massless scalar field show that the big-bang singularity can be replaced by a big quantum bounce. To gain further insight on the nature of this bounce, we study the semi-discrete loop quantum…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Pablo Laguna

We review a recent proposal towards a microscopic understanding of the entropy of non-supersymmetric spacetimes -- with emphasis on the Schwarzschild black hole. The approach is based at an intermediate step on the description of the…

High Energy Physics - Theory · Physics 2007-05-23 Axel Krause

We canonically quantize the dynamics of the brane universe embedded into the five-dimensional Schwarzschild-anti-deSitter bulk space-time. We show that in the brane-world settings the formulation of the quantum cosmology, including the…

General Relativity and Quantum Cosmology · Physics 2009-11-10 A. Boyarsky , A. Neronov , I. Tkachev

In the derivation of holographic dark energy density, the area law of the black hole entropy plays a crucial role. However, the entropy-area relation can be modified from the inclusion of quantum effects, motivated from the loop quantum…

General Physics · Physics 2012-03-12 Ahmad Sheykhi , Kayoomars Karami , Mubasher Jamil , E. Kazemi , M. Haddad

We consider the simplest scenario when black strings / cigars penetrate the cosmological brane. As a result, the brane has a Swiss-cheese structure, with Schwarzschild black holes immersed in a Friedmann-Lema\^{\i}tre-Robertson-Walker…

High Energy Physics - Theory · Physics 2009-11-11 László Á. Gergely

The observed late-time acceleration of the Universe may be the result of unknown physical processes involving either modifications of gravitation theory or the existence of new fields in high energy physics. In the former case, such…

Astrophysics · Physics 2008-11-26 N. Pires , Zong-Hong Zhu , J. S. Alcaniz

The present day accelerated expansion of the universe is naturally addressed within the Brans-Dicke theory just by using holographic dark energy model with inverse of Hubble scale as IR cutoff. It is also concluded that if the universe…

General Relativity and Quantum Cosmology · Physics 2015-05-13 Bibekananda Nayak , Lambodar Prasad Singh

Inspired by the Covid-$19$ virus structure, Barrow argued that quantum-gravitational effects may introduce intricate, fractal features on the black hole horizon [Phys. Lett. B {\bf808} (2020) 135643]. In this viewpoint, black hole entropy…

General Relativity and Quantum Cosmology · Physics 2021-06-09 Ahmad Sheykhi

We discuss the cosmological evolution of a 3-brane Universe in the presence of energy influx from the bulk. We show that this influx can lead to accelerated expansion on the brane, depending on the equations of state of the bulk and brane…

High Energy Physics - Theory · Physics 2009-11-07 N. Tetradis
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