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We describe a non-perturbative approach to studying the gravitational collapse of a scalar field in spherical symmetry with quantum gravity corrections. Quantum effects are described by a phase space function that modifies the constraints…

General Relativity and Quantum Cosmology · Physics 2011-09-15 Andreas Kreienbuehl , Viqar Husain , Sanjeev S. Seahra

We will make a comparison between the dynamics of spherical gravitational collapse for a perturbed FLRW universe to first order in the context of general relativity, with the corresponding results obtained for the gravitational collapse…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-12 César Peralta , Leonardo Castañeda

The gravitational collapse of a spherical distribution, in a class of f(R) theories of gravity, where f(R) is power function of R, is discussed. The spacetime is assumed to admit a homothetic Killing vector. In the collapsing modes, some of…

General Relativity and Quantum Cosmology · Physics 2016-07-28 Soumya Chakrabarti , Narayan Banerjee

We study the gravitational collapse of a massless scalar field within the effective scenario of loop quantum gravity. Classical singularity is avoided and replaced by a quantum bounce in this model. It is shown that, quantum gravity effects…

General Relativity and Quantum Cosmology · Physics 2014-05-02 Yaser Tavakoli , Joao Marto , Andrea Dapor

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

Numerical simulations are performed of a test scalar field in a spacetime undergoing gravitational collapse. The behavior of the scalar field near the singularity is examined and implications for generic singularities are discussed. In…

General Relativity and Quantum Cosmology · Physics 2011-09-12 Ryo Saotome , Ratindranath Akhoury , David Garfinkle

Several examples are known where quantum gravity effects resolve the classical big bang singularity by a bounce. The most detailed analysis has probably occurred for loop quantum cosmology of isotropic models sourced by a free, massless…

General Relativity and Quantum Cosmology · Physics 2008-12-18 Martin Bojowald

In this paper we study the flat (k=0) cosmological FRW model with holonomy corrections of Loop Quantum Gravity. The considered universe contains a massless scalar field and the cosmological constant Lambda. We find analytical solutions for…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Jakub Mielczarek , Tomasz Stachowiak , Marek Szydlowski

We describe a class of exactly soluble models for gravitational collapse in spherical symmetry obtained by patching dynamical spherically symmetric exterior spacetimes with cosmological interior spacetimes. These are generalizations of the…

General Relativity and Quantum Cosmology · Physics 2013-05-29 Benjamin K. Tippett , Viqar Husain

We investigate the bounce cosmology induced by inhomogeneous viscous fluids in FRW space-time (non necessarly flat), taking into account the early-time acceleration after the bounce. Different forms for the scale factor and several examples…

General Relativity and Quantum Cosmology · Physics 2015-09-21 Ratbay Myrzakulov , Lorenzo Sebastiani

The gravitational collapse of spherical, barotropic perfect fluids is analyzed here. For the first time, the final state of these systems is studied without resorting to simplifying assumptions - such as self-similarity - using a new…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Roberto Giambo' , Fabio Giannoni , Giulio Magli , Paolo Piccione

We study the collapse of spherical cold clouds beyond black hole formation to investigate the possibility of a bounce in the in-falling matter when a critical density or pressure is reached. As a first step, we analyse the pressureless…

General Relativity and Quantum Cosmology · Physics 2025-01-24 Swaraj Pradhan , Michael Gabler , Enrique Gaztañaga

We study the spatially homogeneous relativistic Boltzmann equation for massless particles in an FLRW background with scattering kernels in a certain range of soft and hard potentials. We obtain the future global existence of small solutions…

Analysis of PDEs · Mathematics 2021-03-17 Ho Lee

We consider the gravitational collapse of a spherically symmetric homogeneous matter distribution consisting of a Weyssenhoff fluid in the presence of a negative cosmological constant. Our aim is to investigate the effects of torsion and…

General Relativity and Quantum Cosmology · Physics 2017-04-19 Amir Hadi Ziaie , Paulo Vargas Moniz , Arash Ranjbar , Hamid Reza Sepangi

Quantum effects are expected to modify the cosmological dynamics of the early universe while maintaining some (potentially discrete) notion of space-time structure. In one approach, loop quantum cosmology, current models are shown here to…

General Relativity and Quantum Cosmology · Physics 2026-04-29 Martin Bojowald , Manuel Diaz , Erick I. Duque

We model the gravitational collapse of heavy massive shells including its main quantum corrections. Among these corrections, quantum improvements coming from Quantum Einstein Gravity are taken into account, which provides us with an…

General Relativity and Quantum Cosmology · Physics 2015-06-19 R. Torres , F. Fayos

Examining the relativistic collapse of a spherical spacetime where gravity is coupled with a scalar field, this review provides a thorough analysis of some of the most relevant studies from both analytical and numerical perspectives. The…

General Relativity and Quantum Cosmology · Physics 2024-05-09 Roberto Giambò

In this paper we present the techniques for computing cosmological bounces in polynomial $f(R)$ theories, whose order is more than two, for spatially flat FLRW spacetime. In these cases the conformally connected Einstein frame shows up…

General Relativity and Quantum Cosmology · Physics 2016-02-17 Kaushik Bhattacharya , Saikat Chakrabarty

Models of gravitational collapse provide important means to test whether non-classical space-time effects motivated for instance by quantum gravity can be realized in generic ways in physically relevant situations. Here, a detailed analysis…

General Relativity and Quantum Cosmology · Physics 2025-02-19 Martin Bojowald , Erick I. Duque , Dennis Hartmann

In recent years, Loop Quantum Gravity has emerged as a solid candidate for a nonperturbative quantum theory of General Relativity. It is a background independent theory based on a description of the gravitational field in terms of…

General Relativity and Quantum Cosmology · Physics 2009-10-16 Guillermo A. Mena Marugan
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