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We study the gravitational collapse of a homogeneous time-dependent scalar field that, besides its coupling to curvature, it is also kinematically coupled to the Einstein tensor. This coupling is a part of the Horndeski theory and we…

General Relativity and Quantum Cosmology · Physics 2017-04-19 George Koutsoumbas , Konstantinos Ntrekis , Eleftherios Papantonopoulos , Minas Tsoukalas

We investigate here spherically symmetric gravitational collapse in a spacetime with an arbitrary number of dimensions and with a general {\it type I} matter field, which is a broad class that includes most of the physically reasonable…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Rituparno Goswami , Pankaj S Joshi

We present results from a numerical study of spherical gravitational collapse in shift symmetric Einstein dilaton Gauss-Bonnet (EdGB) gravity. This modified gravity theory has a single coupling parameter that when zero reduces to general…

General Relativity and Quantum Cosmology · Physics 2019-10-16 Justin L Ripley , Frans Pretorius

The present work investigates the gravitational collapse of a perfect fluid in $f(R)$ gravity models. For a general $f(R)$ theory, it is shown analytically that a collapse is quite possible. The singularity formed as a result of the…

General Relativity and Quantum Cosmology · Physics 2016-03-30 Soumya Chakrabarti , Narayan Banerjee

We compare the gravitational collapse of homogeneous perfect fluid with various equations of state in the framework of General Relativity and in $R^2$ gravity. We make our calculations using dimensionless time with characteristic timescale…

General Relativity and Quantum Cosmology · Physics 2019-03-27 Artyom V. Astashenok , Karim Mosani , Sergey D. Odintsov , Gauranga C. Samanta

A new solution for the endpoint of gravitational collapse is proposed. By extending the concept of Bose-Einstein condensation to gravitational systems, a cold, compact object with an interior de Sitter condensate phase and an exterior…

General Relativity and Quantum Cosmology · Physics 2023-02-16 Pawel O. Mazur , Emil Mottola

We study the process of gravitational collapse in pure Gauss-Bonnet gravity. In the homogeneous dust collapse, we show that the $D=7$ pure Gauss-Bonnet theory has gravitational dynamics indistinguishable from Einstein's theory in $D=4$,…

General Relativity and Quantum Cosmology · Physics 2023-06-21 Konstantinos F. Dialektopoulos , Daniele Malafarina , Naresh Dadhich

We investigate here the gravitational collapse end states for a spherically symmetric perfect fluid with an equation of state $p=k\rho$. It is shown that given a regular initial data in terms of the density and pressure profiles at the…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Rituparno Goswami , Pankaj S Joshi

The present work deals with dynamics of gravitational collapse with cylindrical symmetry as developed by Misner and Sharp. The interior collapsing anisotropic cylindrical perfect fluid is matched to an exterior vacuum cylindrically…

General Relativity and Quantum Cosmology · Physics 2016-03-08 Sanjukta Chakraborty , Subenoy Chakraborty

A new final state of gravitational collapse is proposed. By extending the concept of Bose-Einstein condensation to gravitational systems, a cold, dark, compact object with an interior de Sitter condensate $p_{_V} = -\rho_{_V}$ and an…

General Relativity and Quantum Cosmology · Physics 2009-10-19 Pawel O. Mazur , Emil Mottola

We point out that although the pioneering work of Oppenheimer and Snyder (OS), technically, indicated the formation of an event horizon for a collapsing homogeneous dust ball of mass $M_b$ and radius $R_b$, the Eqs. (32) and (36) of their…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Abhas Mitra

We consider gravitational collapse in the recently proposed 4D limit of Einstein-Gauss-Bonnet gravity. We show that for collapse of a sphere made of homogeneous dust the process is qualitatively similar to the case of pure Einstein's…

General Relativity and Quantum Cosmology · Physics 2020-06-04 Daniele Malafarina , Bobir Toshmatov , Naresh Dadhich

We investigate here gravitational collapse of a perfect fluid with a linear isentropic equation of state $p = k \rho$. A class of collapse models is given which is a family of solutions to Einstein equations and the final fate of collapse…

General Relativity and Quantum Cosmology · Physics 2015-02-24 Sanjay Sarwe , R. V. Saraykar , Pankaj S. Joshi

Emergent modified gravity is a canonical theory based on general covariance where the spacetime is not fundamental, but rather an emergent object. This feature allows for modifications of the classical theory and can be used to model new…

General Relativity and Quantum Cosmology · Physics 2024-02-06 Erick I. Duque

The dynamics of the gravitational collapse is examined in the realm of string based formalism of D-branes that encompass General Relativity as a low energy limit. A complete analytical solution is given to the spherically symmetric collapse…

General Relativity and Quantum Cosmology · Physics 2009-08-04 R. Maier , I. Damião Soares

Motivated by the geometrical interpretation of Brans-Dicke (BD) scalar field which may also act as a torsion potential in Lyra geometry, we study the effects of spacetime torsion on the dynamics of a collapsing massive star. Taking the…

General Relativity and Quantum Cosmology · Physics 2015-01-13 Amir Hadi Ziaie , Arash Ranjbar , Hamid Reza Sepangi

The spherical gravitational collapse of a compact packet consisting of perfect fluid is studied. The spacetime outside the fluid packet is described by the out-going Vaidya radiation fluid. It is found that when the collapse has continuous…

General Relativity and Quantum Cosmology · Physics 2009-10-31 J. F. Villas da Rocha , Anzhong Wang , N. O. Santos

In general, to avoid a singularity in cosmological models involves the introduction of exotic kind of matter fields, for example, a scalar field with negative energy density. In order to have a bouncing solution in classical General…

General Relativity and Quantum Cosmology · Physics 2019-10-23 O. Galkina , J. C. Fabris , F. T. Falciano , N. Pinto-Neto

A combined BCDE (Brans-Dicke and Einstein-Cartan) theory with lambda-term is developed through Raychaudhuri's equation, for inflationary scenario. It involves a variable cosmological constant, which decreases with time, jointly with energy…

General Physics · Physics 2008-11-26 Marcelo Samuel Berman

In singularity generating spacetimes both the out-going and in-going expansions of null geodesic congruences $\theta ^{+}$ and $\theta ^{-}$ should become increasingly negative without bound, inside the horizon. This behavior leads to…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Manasse R. Mbonye , Demosthenes Kazanas