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We make use of an improved existence result for the characteristic initial value problem for the conformal Einstein equations to show that given initial data on two null hypersurfaces $\mathcal{N}_\star$ and $\mathcal{N}'_\star$ such that…

General Relativity and Quantum Cosmology · Physics 2024-06-19 Peng Zhao , David Hilditch , Juan A. Valiente Kroon

In this paper we analyze the conformal Einstein equations to all orders at null infinity without imposing any restriction on the spacetime dimension, the topology of $\mathscr{I}$, or fall-off conditions for the Weyl tensor. In particular,…

General Relativity and Quantum Cosmology · Physics 2026-02-06 Marc Mars , Gabriel Sánchez-Pérez

In principle, global properties of solution of Einstein equations need to be addressed using the conformal Einstein equations, because this conformal compactification allows a clean definition of the `infinities' (spacelike, timelike and…

General Relativity and Quantum Cosmology · Physics 2025-07-14 Thomas Mädler , Emanuel Gallo

A classical model for the extension of singular spacetime geometries across their singularities is presented. The regularization introduced by this model is based on the following observation. Among the geometries that satisfy Einstein's…

General Relativity and Quantum Cosmology · Physics 2010-11-23 Eran Rosenthal

There are a number of publications on relativistic objects dealing either with black holes or naked singularities in the center. Here we show that there exist static spherically symmetric solutions of Einstein equations with a strongly…

General Relativity and Quantum Cosmology · Physics 2024-08-27 O. S. Stashko , V. I. Zhdanov

We present a new formulation of Einstein's equations for an axisymmetric spacetime with vanishing twist in vacuum. We propose a fully constrained scheme and use spherical polar coordinates. A general problem for this choice is the…

General Relativity and Quantum Cosmology · Physics 2015-05-15 Christian Schell , Oliver Rinne

We find new classes of exact solutions of the initial momentum constraint for vacuum Einstein's equations. Considered data are either invariant under a continuous symmetry or they are assumed to have the exterior curvature tensor of a…

General Relativity and Quantum Cosmology · Physics 2018-01-01 J. Tafel , M. Jóźwikowski

We initiate a systematic study of Einstein-Gauss-Bonnet gravity in the presence of boundaries subject to conformal boundary conditions, in which the conformal class of the boundary metric is kept fixed. In Einstein gravity, the trace of the…

High Energy Physics - Theory · Physics 2026-02-18 Damián A. Galante , Robert C. Myers , Themistocles Zikopoulos

We propose a nonlocal field theory for gravity in presence of matter consistent with perturbative unitarity, quantum finiteness, and other essential classical properties that we are going to list below. First, the theory exactly reproduces…

General Relativity and Quantum Cosmology · Physics 2021-03-09 Leonardo Modesto

We propose a revised formulation of General Relativity for cosmological settings, in which the Einstein constant varies with the energy density of the Universe. We demonstrate that this modification has only phenomenological impact of…

General Relativity and Quantum Cosmology · Physics 2025-08-28 Giovanni Montani , Giulia Maniccia , Elisa Fazzari , Alessandro Melchiorri

We investigate the future asymptotics of spatially homogeneous space-times with a positive cosmological constant by using and further developing geometric conformal methods in General Relativity. For a large class of source fields,…

General Relativity and Quantum Cosmology · Physics 2023-02-06 Christian Lübbe , Filipe C. Mena

Recent results on solutions of the Einstein equations with matter are surveyed and a number of open questions are stated. The first group of results presented concern asymptotically flat spacetimes, both stationary and dynamical. Then there…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Alan D. Rendall

This is the first of a series of papers describing a numerical implementation of the conformally rescaled Einstein equation, an implementation designed to calculate asymptotically flat spacetimes, especially spacetimes containing black…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Peter Huebner

We study the solutions of the semiclassical Einstein equation in flat cosmological spacetimes driven by a massive conformally coupled scalar field. In particular, we show that it is possible to give initial conditions at finite time to get…

Mathematical Physics · Physics 2015-03-10 Nicola Pinamonti , Daniel Siemssen

Recently the neglected issue of the causal structure in the flat spacetime approach to Einstein's theory of gravity has been substantially resolved. Consistency requires that the flat metric's null cone be respected by the null cone of the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 J. Brian Pitts , W. C. Schieve

We consider a system representing self-gravitating balls of dust in an expanding Universe. It is demonstrated that one can prescribe data for such a system at infinity and evolve it backward in time without the development of shocks or…

General Relativity and Quantum Cosmology · Physics 2022-06-29 Shabnam Beheshti , Mikael Normann , Juan Valiente Kroon

We continue recent work and formulate the gravitational vacuum Einstein equations over a locally finite spacetime by using the basic axiomatics, techniques, ideas and working philosophy of Abstract Differential Geometry. The whole…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Anastasios Mallios , Ioannis Raptis

Generalized symmetries of the Einstein equations are infinitesimal transformations of the spacetime metric that formally map solutions of the Einstein equations to other solutions. The infinitesimal generators of these symmetries are…

General Relativity and Quantum Cosmology · Physics 2009-10-22 C. G. Torre , I. M. Anderson

We describe in this article a new code for evolving axisymmetric isolated systems in general relativity. Such systems are described by asymptotically flat space-times which have the property that they admit a conformal extension. We are…

General Relativity and Quantum Cosmology · Physics 2009-11-07 J. Frauendiener , Matthias Hein

The existence and nature of singularities in locally spatially homogeneous solutions of the Einstein equations coupled to various phenomenological matter models is investigated. It is shown that, under certain reasonable assumptions on the…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Alan D. Rendall