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We investigate here quantum effects in gravitational collapse of a scalar field model which classically leads to a naked singularity. We show that non-perturbative semi-classical modifications near the singularity, based on loop quantum…

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

Various types of inhomogeneous collapse models in general relativity (GR) lead to the formation of spacetime singularities either visible or hidden by a spacetime horizon. Our aim in the present work is to search for nonsingular models in…

General Relativity and Quantum Cosmology · Physics 2025-07-04 Akbar Jahan , Halime Miraghaei , Shayesteh Ghaffari , Amir Hadi Ziaie

A self-similar formalism for the study of the gravitational collapse of molecular gas provides an important theoretical framework from which to explore the dynamics of star formation. Motivated by the presence of elongated and filamentary…

Solar and Stellar Astrophysics · Physics 2015-05-13 Lisa Holden , Kevin Hoppins , Benjamin Baxter , Marco Fatuzzo

This paper considers the quantum collapse of infinitesimally thin dust shells in 2+1 gravity. In 2+1 gravity a shell is no longer a sphere but a ring of matter. The classical equation of motion has been considered by Peleg and Steif and…

General Relativity and Quantum Cosmology · Physics 2008-11-26 L. Ortíz , M. P. Ryan

We study the occurrence of shell crossing in spherical weakly charged dust collapse in the presence of a non-vanishing cosmological constant. We find that shell crossing always occurs from generic time-symmetric regular initial data, near…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Sergio M. C. V. Goncalves

The general formulas of a non-rotating dynamic thin shell that connects two arbitrary cylindrical regions are given using Israel's method. As an application of them, the dynamics of a thin shell made of counter-rotating dust particles,…

General Relativity and Quantum Cosmology · Physics 2014-11-17 P. R. C. T. Pereira , Anzhong Wang

We give a review of recent work aimed at understanding the dynamics of gravitational collapse in quantum gravity. Its goal is to provide a non-perturbative computational framework for understanding the emergence of the semi-classical…

General Relativity and Quantum Cosmology · Physics 2008-01-09 Viqar Husain

We present an idealised model of gravitational collapse, describing a collapsing rotating cylindrical shell of null dust in flat space, with the metric of a spinning cosmic string as the exterior. We find that the shell bounces before…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Filipe C. Mena , Jose Natario , Paul Tod

We analyze the evolution of a homogenous and pressureless ball of dust (or "star") in ghost-free massive gravity on de Sitter spacetime. We find that gravitational collapse does not take place for all parameters of the massive gravity…

High Energy Physics - Theory · Physics 2021-09-23 Roman Berens , Luke Krauth , Rachel A. Rosen

We study gravitational collapse in effective loop quantum gravity, focusing on non-marginally bound configurations in Lema\^itre-Tolman-Bondi spacetimes. In the homogeneous limit we recover the effective dynamics of loop quantum cosmology…

General Relativity and Quantum Cosmology · Physics 2024-09-06 Lorenzo Cipriani , Francesco Fazzini , Edward Wilson-Ewing

I present the first analytical study of gravitational collapse in a compact CMC foliation with $S^3$ spatial topology. The solutions I find, in this context, will be both solutions of Shape Dynamics and General Relativity. The aim is to…

General Relativity and Quantum Cosmology · Physics 2017-04-14 Flavio Mercati

To study the interaction of star-formation and turbulent molecular cloud structuring, we analyse numerical models and observations of self-gravitating clouds using the Delta-variance as statistical measure for structural characteristics. In…

Astrophysics · Physics 2009-11-07 Volker Ossenkopf , Ralf Klessen , Fabian Heitsch

Inhomogeneous cosmological models have recently become a very interesting alternative to standard cosmology. This is because these models are able to fit cosmological observations without the need for dark energy. However, due to…

Astrophysics · Physics 2009-11-13 Krzysztof Bolejko , Paul Lasky

We study the end stages of gravitational collapse of the thin shell of matter in ingoing Eddington-Finkelstein coordinates. We use the functional Schrodinger formalism to capture quantum effects in the near singularity limit. We find that…

General Relativity and Quantum Cosmology · Physics 2015-06-18 Anshul Saini , Dejan Stojkovic

Assuming the weak energy condition, we study the nature of the non-central shell-focussing singularity which can form in the gravitational collapse of a spherical compact object in classical general relativity. We show that if the radial…

General Relativity and Quantum Cosmology · Physics 2009-10-28 F. I. Cooperstock , S. Jhingan , P. S. Joshi , T. P. Singh

We investigate spherically symmetric gravitational collapse of thick matter shell without radiation in the Einstein gravity with cosmological constant. The orbit of the infalling thick matter is determined by imposing an equation of state…

General Relativity and Quantum Cosmology · Physics 2023-01-10 Shuichi Yokoyama

We numerically study the dynamics of an imploding hollow cylinder composed of dust. Since there is no cylindrical black hole in 4-dimensional spacetime with physically reasonable energy conditions, a collapsed dust cylinder involves a naked…

General Relativity and Quantum Cosmology · Physics 2009-11-19 Ken-ichi Nakao , Tomohiro Harada , Yasunari Kurita , Yoshiyuki Morisawa

In the case of the energy-momentum tensor related to "ordinary" matter (perfect fluid representing spin 1/2 and 1 fields), the equations of general relativity result in cosmological and gravitational collapse singularities--due to the…

General Physics · Physics 2009-11-19 Vladimir Mashkevich

There is a viable vector-tensor gravity (VTG) theory, whose vector field produces repulsive forces leading to important effects. In the background universe, the effect of these forces is an accelerated expansion identical to that produced…

General Relativity and Quantum Cosmology · Physics 2020-12-01 R. Dale , D. Sáez

Quantum-mechanical model of self-gravitating dust shell is considered. To clarify the relation between classical and quantum spacetime which the shell collapse form, we consider various time slicing on which quantum mechanics is developed.…

General Relativity and Quantum Cosmology · Physics 2011-09-09 K. Nakamura , Y. Oshiro , A. Tomimatsu