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It has been claimed that the Lemaitre-Tolman-Bondi-de Sitter solution always admits future-pointing radial time-like geodesics emerging from the shell-focussing singularity, regardless of the nature of the (regular) initial data. This is…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Brien C. Nolan , Filipe C. Mena , Sergio M. C. V. Goncalves

We study finite-time future singularities in $\mathcal{F}(R,G)$-gravity, where $R$ and $G$ are the Ricci scalar and the Gauss-Bonnet invariant, respectively. In particular, we reconstruct the $F(G)$-gravity and $\mathcal{F}(R,G)$-gravity…

General Relativity and Quantum Cosmology · Physics 2015-05-19 Lorenzo Sebastiani

Previous papers dealt with the quantization of the Lemaitre-Tolman-Bondi (LTB) model for vanishing cosmological constant $\Lambda$. Here we extend the analysis to the case $\Lambda >0$. Our main goal is to present solutions of the…

General Relativity and Quantum Cosmology · Physics 2010-01-06 Anne Franzen , Sashideep Gutti , Claus Kiefer

Lemaitre-Tolman-Bondi models as specific spherically symmetric solutions of general relativity simplify in their reduced form some of the mathematical ingredients of black hole or cosmological applications. The conditions imposed in…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald , Tomohiro Harada , Rakesh Tibrewala

We study here the structure of singularity forming in gravitational collapse of spherically symmetric inhomogeneous dust. Such a collapse is described by the Tolman-Bondi-Lema{\^i}tre metric, which is a two-parameter family of solutions to…

General Relativity and Quantum Cosmology · Physics 2007-05-23 S. Jhingan , P. S. Joshi

We analyse here the gravitational collapse of directed null radiation in a background with a constant potential such as one produced by a star system like galaxy in which the collapsing object is immersed. Both naked singularities and black…

General Relativity and Quantum Cosmology · Physics 2009-10-31 S. Jhingan , N. Dadhich , P. S. Joshi

The properties of future singularities are investigated in the universe dominated by dark energy including the phantom-type fluid. We classify the finite-time singularities into four classes and explicitly present the models which give rise…

High Energy Physics - Theory · Physics 2009-09-17 Shin'ichi Nojiri , Sergei D. Odintsov , Shinji Tsujikawa

LeMa\^\i tre-Tolman-Bondi models of spherical dust collapse have been used and continue to be used extensively to study various stellar collapse scenarios. It is by now well-known that these models lead to the formation of black holes and…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Cenalo Vaz , Louis Witten , T. P. Singh

The existence of spacetime singularities is one of the biggest problems of nowadays physics. According to Penrose, each physical singularity should be covered by a "cosmic censor" which prevents any external observer from perceiving their…

General Relativity and Quantum Cosmology · Physics 2018-08-15 Alfio Bonanno , Benjamin Koch , Alessia Platania

We consider a "Scalar-Einstein-Gauss-Bonnet" theory in four dimension, where the scalar field couples non minimally with the Gauss-Bonnet (GB) term. This coupling with the scalar field ensures the non topological character of the GB term.…

High Energy Physics - Theory · Physics 2018-04-04 Narayan Banerjee , Tanmoy Paul

In this work we study the dynamics of gravitational collapse of a homogeneous dust sphere in a model exhibiting a linear non-minimal coupling between matter and curvature. The evolution of the scale factor and the matter density is obtained…

General Relativity and Quantum Cosmology · Physics 2012-12-12 J. Páramos , C. Bastos

The dynamics of collapsing and expanding cylindrically symmetric gravitational and matter fields with lightlike wave-fronts is studied in General Relativity, using the Barrabes-Israel method. As an application of the general formulae…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Paulo R. C. T. Pereira , A. Z. Wang

We consider general relativistic homogeneous gravitational collapses for dust and radiation. We show that replacing the density profile with an effective density justified by some quantum gravity framework leads to the avoidance of the…

General Relativity and Quantum Cosmology · Physics 2013-08-07 Cosimo Bambi , Daniele Malafarina , Leonardo Modesto

Quantum gravity effects are likely to play a crucial role in determining the outcome of gravitational collapse during its final stages. In this contribution we will outline a canonical quantization of the LeMaitre-Tolman-Bondi models, which…

General Relativity and Quantum Cosmology · Physics 2011-12-01 Cenalo Vaz , Louis Witten

We use the conformal approach to numerical relativity to evolve hyperboloidal gravitational wave data without any symmetry assumptions. Although our grid is finite in space and time, we cover the whole future of the initial data in our…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Peter Huebner

We consider here the effects of a non-vanishing cosmological term on the final fate of a spherical inhomogeneous collapsing dust cloud. It is shown that depending on the nature of the initial data from which the collapse evolves, and for a…

General Relativity and Quantum Cosmology · Physics 2009-10-31 S. S. Deshingkar , S. Jhingan , A. Chamorro , P. S. Joshi

We study the gravitational collapse of a dust dark matter star in a $\Lambda$-background. We consider two distinct cases: First we do not have a dark matter and dark energy coupling; second, we consider that $\Lambda $ decay in dark…

General Relativity and Quantum Cosmology · Physics 2007-05-23 M. de Campos

It was long believed that the singularity inside a realistic, rotating black hole must be spacelike. However, studies of the internal geometry of black holes indicate a more complicated structure is typical. While it seems likely that an…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Patrick R Brady , Serge Droz , Sharon M Morsink

We derive some more results on the nature of the singularities arising in the collapse of inhomogeneous dust spheres. (i) It is shown that there are future-pointing radial and non-radial time-like geodesics emerging from the singularity if…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Brien C. Nolan , Filipe C. Mena

In [1] a new cosmological model is proposed with no big bang singularity in the past, though past geodesically incomplete. This model starts with an inflationary era, follows with a stiff matter dominated period and evolves to accelerated…

General Relativity and Quantum Cosmology · Physics 2016-08-09 L. Fernandez-Jambrina
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