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Based on modifications inspired from loop quantum gravity (LQG), spherically symmetric models have recently been explored to understand the resolution of classical singularities and the fate of the spacetime beyond. While such…

General Relativity and Quantum Cosmology · Physics 2023-08-23 Kristina Giesel , Hongguang Liu , Parampreet Singh , Stefan Andreas Weigl

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

Coherent or semiclassical states in canonical quantum gravity describe the classical Schwarzschild space-time. By tracing over the coherent state wavefunction inside the horizon, a density matrix is derived. Bekenstein-Hawking entropy is…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Arundhati Dasgupta

A simple position probability density formulation is presented for the motion of a particle in a spherically symmetric potential. The approach provides an alternative to Newtonian methods for presentation in an elementary course, and…

Physics Education · Physics 2007-05-23 Lorenzo J. Curtis , David G. Ellis

Gravitational collapse in (n+2) dimensional quasi-spherical space-time is studied for a fluid with non vanishing radial pressure. An exact analytic solution is obtained (ignoring the arbitrary integration function) for the equation of state…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Sanjukta Chakraborty , Subenoy Chakraborty , Ujjal Debnath

It is argued that quantum states of geometry, like those of particles, should be coherent on light cones of any size. An exact classical solution, the gravitational shock wave of a relativistic point particle, is used to estimate…

General Relativity and Quantum Cosmology · Physics 2021-02-03 Craig Hogan

Geometric quantization is an attempt at using the differential-geometric ingredients of classical phase spaces regarded as symplectic manifolds in order to define a corresponding quantum theory. Generally, the process of geometric…

Mathematical Physics · Physics 2018-01-09 Andrea Carosso

All objects in 4D spacetime may in principle travel on null paths in a 5D mani-fold. We use this, together with a change in the extra coordinate and the signature of the metric, to construct a simple model of a classical universe and a…

General Relativity and Quantum Cosmology · Physics 2009-03-17 Paul S. Wesson

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

Asymptotic safety (an ultraviolet fixed point with finite-dimensional critical surface) offers the possibility that a predictive theory of quantum gravity can be obtained from the quantization of classical general relativity. However, it is…

General Relativity and Quantum Cosmology · Physics 2011-06-27 Roberto Casadio , Stephen D. H. Hsu , Behrouz Mirza

In a metric variable based Hamiltonian quantization, we give a prescription for constructing semiclassical matter-geometry states for homogeneous and isotropic cosmological models. These "collective" states arise as infinite linear…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Viqar Husain , Oliver Winkler

We study the quantum gravitational collapse of spherically symmetric pressureless dust. Using an effective equation derived from a polymer quantization in the connection-triad phase space variables of general relativity, we find…

General Relativity and Quantum Cosmology · Physics 2022-03-23 Viqar Husain , Jarod George Kelly , Robert Santacruz , Edward Wilson-Ewing

We give a formulation of quantum cosmology with a pressureless dust and arbitrary additional matter fields. The system has the property that its Hamiltonian constraint is linear in the dust momentum. This feature provides a natural time…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Viqar Husain , Tomasz Pawlowski

The Einstein action for the gravitational field has some properties which make of it, after quantization, a rare prototype of systems with quantum configurations that do not have a classical analogue. Assuming spherical symmetry in order to…

General Relativity and Quantum Cosmology · Physics 2020-06-23 G. Modanese

It is expected that the quantum nature of spacetime leaves its imprint in all semiclassical gravitational systems, at least in certain regimes, including gravitational waves. In this paper we investigate such imprints on gravitational waves…

General Relativity and Quantum Cosmology · Physics 2021-11-01 Andrea Dapor , Klaus Liegener

A unified theory of four-dimensional gravity together with the standard model is presented, with supersymmetry breaking of M-theory at a TeV. Masses of the the known particles are derived. The cosmological constant is quantum generated to…

High Energy Physics - Theory · Physics 2007-05-23 Gordon Chalmers

We investigate the fate of the classical singularity in a collapsing dust cloud. For this purpose, we quantize the marginally bound Lemaitre-Tolman-Bondi model for spherically-symmetric dust collapse by considering each dust shell in the…

General Relativity and Quantum Cosmology · Physics 2019-06-19 Claus Kiefer , Tim Schmitz

The causal interpretation of quantum mechanics is applied to a homogeneous and isotropic quantum universe, whose matter content is composed by non interacting dust and radiation. For wave functions which are eigenstates of the total dust…

General Relativity and Quantum Cosmology · Physics 2009-11-11 N. Pinto-Neto , E. Sergio Santini , F. T. Falciano

Quantum cosmology may restrict the class of gauge models which unify electroweak and strong interactions. In particular, if one studies the normalizability criterion for the one-loop wave function of the universe in a de Sitter background…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Giampiero Esposito , Alexander Yu. Kamenshchik , Gennaro Miele

A regular (i.e., singularity-free) cycling cosmological model is advanced. In the model, there are only two constants: the gravitational constant (or the Planck time) and the cosmic period. The radius of the universe is a simple periodic…

General Physics · Physics 2011-12-30 Vladimir S. Mashkevich