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We show that the quantum dynamics of a thin spherical shell in general relativity is equivalent to the Coulomb-Dirac equation on the half line. The Hamiltonian has a one-parameter family of self-adjoint extensions with a discrete energy…

General Relativity and Quantum Cosmology · Physics 2018-07-05 Syed Moeez Hassan , Viqar Husain , Jonathan Ziprick

The effective description of loop quantum cosmology (LQC) has proved to be a convenient platform to study phenomenological implications of the quantum bounce that resolves the classical big-bang singularity. Originally, this description was…

General Relativity and Quantum Cosmology · Physics 2015-11-04 Abhay Ashtekar , Brajesh Gupt

The issue of the local visibility of the shell-focussing singularity in marginally bound spherical dust collapse is considered from the point of view of the existence of future-directed null geodesics with angular momentum which emanate…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Filipe C Mena , Brien C Nolan

We analyze the stability of the Cauchy horizon associated with a globally naked, shell-focussing singularity arising from the complete gravitational collapse of a spherical dust cloud. In previous work, we have studied the dynamics of…

General Relativity and Quantum Cosmology · Physics 2018-01-09 Néstor Ortiz , Olivier Sarbach

We investigate the fully relativistic spherical collapse model of a uniform distribution of mass $M$ with initial comoving radius $\chi_*$ and spatial curvature $k \equiv 1/\chi_k^2 \le 1/\chi_*^2$ representing an over-density or bounded…

General Relativity and Quantum Cosmology · Physics 2025-06-02 Enrique Gaztanaga , K. Sravan Kumar , Swaraj Pradhan , Michael Gabler

In this paper we study the gravitational collapse in loop quantum gravity. We consider the space-time region inside the Schwarzschild black hole event horizon and we divide this region in two parts, the first one where the matter (dust…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Leonardo Modesto

We show that the quantization ambiguities of loop quantum cosmology, when considered in wider generality, can be used to produce discretionary dynamical behavior. There is an infinite dimensional space of ambiguities which parallels the…

General Relativity and Quantum Cosmology · Physics 2023-05-03 Lautaro Amadei , Alejandro Perez , Salvatore Ribisi

In a recent paper (Hajdukovic 2020a) quantum vacuum was considered as a source of gravity and, the simplest phenomenon, the gravitational polarization of the quantum vacuum by an immersed point-like body, was studied. In the present paper,…

General Physics · Physics 2021-04-13 Dragan Hajdukovic

In the path integral formulation of the reduced phase space Loop Quantum Gravity (LQG), we propose a new approach to allow the spatial cubic lattice (graph) to change dynamically in the physical time evolution. The equations of motion of…

General Relativity and Quantum Cosmology · Physics 2021-07-14 Muxin Han , Hongguang Liu

The problem of how space-time responds to gravitating quantum matter in full quantum gravity has been one of the main questions that any program of quantization of gravity should address. Here we analyze this issue by considering the…

General Relativity and Quantum Cosmology · Physics 2016-09-07 Miguel Campiglia , Rodolfo Gambini , Javier Olmedo , Jorge Pullin

We present an algorithm for the construction of conformal coordinates in the interior of a spherically symmetric, collapsing matter cloud in general relativity. This algorithm is based on the numerical integration of the radial null…

General Relativity and Quantum Cosmology · Physics 2014-06-17 Néstor Ortiz , Olivier Sarbach

We use the canonical quantization of spherically symetric dust universes, and calculate the expectation value of the quantized metric, $<\Psi|\hat{g}|\Psi>$. Though the classical solutions are singular, and the wave functions have no zero…

High Energy Physics - Theory · Physics 2007-05-23 Yoav Peleg

We consider here the gravitational collapse of a spherically symmetric inhomogeneous dust cloud described by the Tolman-Bondi models. By studying a general class of these models, we find that the end state of the collapse is either a black…

General Relativity and Quantum Cosmology · Physics 2009-10-22 P. S. Joshi , T. P. Singh

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

We give a characterization of the central shell-focusing curvature singularity that can form in the spherical gravitational collapse of a bounded matter distribution obeying the dominant energy condition. This characterization is based on…

General Relativity and Quantum Cosmology · Physics 2009-10-31 T. P. Singh

In this article we study the influence of magnetic fields on the axial gravitational waves emitted during the collapse of a homogeneous dust sphere. We found that while the energy emitted depends weakly on the initial matter perturbations…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Hajime Sotani , Shijun Yoshida , Kostas D. Kokkotas

We discuss a model describing exactly a thin spherically symmetric shell of matter with zero rest mass. We derive the reduced formulation of this system in which the variables are embeddings, their conjugate momenta, and Dirac observables.…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Petr Hajicek , Claus Kiefer

In general relativity, gravitational collapse of matter fields ends with the formation of a spacetime singularity, where the matter density becomes infinite and standard physics breaks down. According to the weak cosmic censorship…

General Relativity and Quantum Cosmology · Physics 2014-08-05 Lingyao Kong , Daniele Malafarina , Cosimo Bambi

This paper explores the theoretical implications of quantum gravity by analyzing compact stellar objects, presenting three distinct models that serve as alternatives to traditional black holes. These models are characterized by their…

General Relativity and Quantum Cosmology · Physics 2025-12-02 Salvatore Samuele Sirletti , Piero Nicolini , Mariafelicia De Laurentis

In this work we investigate some non-Newtonian effects in exact solutions of the Einstein equations, which describe stationary and axisymmetric configurations of self-gravitating dust. A distinctive feature of these solutions is the…

General Relativity and Quantum Cosmology · Physics 2024-12-18 Matteo Fontana , Federico Scali , Sergio Luigi Cacciatori