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The longstanding issue of general covariance in effective models of quantum gravity is addressed, which arises when canonical quantum gravity leads to a semiclassical model described by an effective Hamiltonian constraint. In the context of…

General Relativity and Quantum Cosmology · Physics 2026-03-05 Cong Zhang , Jerzy Lewandowski , Yongge Ma , Jinsong Yang

Starting from the Oppenheimer-Snyder model, we know how in classical general relativity the gravitational collapse of matter form a black hole with a central spacetime singularity. It is widely believed that the singularity must be removed…

General Relativity and Quantum Cosmology · Physics 2015-02-27 Yiyang Zhang , Yiwei Zhu , Leonardo Modesto , Cosimo Bambi

The low energy effective theory of gravity comprises two elements of quantum theory joined to classical general relativity. The first is the quantum conformal anomaly, which is responsible for macroscopic correlations on light cones and a…

General Relativity and Quantum Cosmology · Physics 2025-02-05 Emil Mottola

In this paper, we treat 4-dimensional Einstein-Gauss-Bonnet gravity as general relativity with an effective stress-energy tensor. We will study the modified Oppenheimer-Snyder-Datt model of the gravitational collapse of a star in a…

General Relativity and Quantum Cosmology · Physics 2023-02-22 R. Hassannejad , A. Sadeghi , F. Shojai

In this paper we study an Oppenheimer-Snyder (OS)-like gravitational collapse in the general framework of scale-dependent gravity. We explore the collapse in spherically symmetric solutions suggested both by asymptotically safe gravity…

General Relativity and Quantum Cosmology · Physics 2025-04-07 Ramin Hassannejad , Gaetano Lambiase , Fabio Scardigli , Fatimah Shojai

The prediction of spacetime singularities, regions of infinite curvature where classical physics breaks down, is one of the most profound challenges in General Relativity (GR). In particular, black hole solutions such as the Schwarzschild…

General Relativity and Quantum Cosmology · Physics 2025-11-18 Jose Pinedo Soto

We give a model of the higher-dimensional spherically symmetric gravitational collapse of a dust cloud in Einstein-Gauss-Bonnet gravity. A simple formulation of the basic equations is given for the spacetime $M \approx M^2 \times K^{n-2}$…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Hideki Maeda

Emergent modified gravity provides a covariant framework for holonomy effects in models of loop quantum gravity with consistent black hole solutions coupled to a scalar field. Several independent studies of the Hawking thermal distribution…

General Relativity and Quantum Cosmology · Physics 2026-02-13 Idrus Husin Belfaqih , Martin Bojowald , Suddhasattwa Brahma , Erick I. Duque

We establish an exact bidirectional map between interior Friedmann density of a collapsing star and exterior static spherically symmetric metric in generalized Oppenheimer-Snyder collapse. This reduces Einstein's differential…

General Relativity and Quantum Cosmology · Physics 2026-05-12 H. Khodabakhshi , Zhi-Chao Li , H. Lu , F. Shojai

Gravity and general relativity are considered as an Effective Field Theory at low energies and macroscopic distances. The effective action of the conformal anomaly of light or massless quantum fields has significant effects on macroscopic…

High Energy Physics - Theory · Physics 2023-02-20 Emil Mottola

Black holes are one of the most fascinating predictions of general relativity. They are the natural product of the complete gravitational collapse of matter and today we have a body of observational evidence supporting the existence of…

General Relativity and Quantum Cosmology · Physics 2023-07-26 Cosimo Bambi

We suggest a Lorentz non-invariant generalization of the unimodular gravity theory, which is classically equivalent to general relativity with a locally inert (devoid of local degrees of freedom) perfect fluid having an equation of state…

General Relativity and Quantum Cosmology · Physics 2017-10-02 A. O. Barvinsky , A. Yu. Kamenshchik

The general properties of a perfect relativistic fluid resulting from the quantum gravitational anomaly are investigated. It is found that, in the limit of a weak gravitational field, this fluid possesses a polytropic equation of state…

High Energy Physics - Theory · Physics 2015-02-09 P. O. Kazinski

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 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

General Relativity receives quantum corrections relevant at macroscopic distance scales and near event horizons. These arise from the conformal scalar degrees of freedom in the extended effective field theory of gravity generated by the…

General Relativity and Quantum Cosmology · Physics 2012-09-25 Emil Mottola

We provide a covariant framework to study singularity-free Lema\^itre-Tolman-Bondi spacetimes with effective corrections motivated by loop quantum gravity. We show that, as in general relativity, physically reasonable energy distributions…

General Relativity and Quantum Cosmology · Physics 2024-03-07 Asier Alonso-Bardaji , David Brizuela

The issue of general covariance in effective quantum gravity models within the Hamiltonian framework is addressed. The previously proposed equations for the covariance condition in spherically symmetric models are explicitly derived. By…

General Relativity and Quantum Cosmology · Physics 2026-03-05 Cong Zhang , Jerzy Lewandowski , Yongge Ma , Jinsong Yang

LeMa\^\i tre-Tolman-Bondi models of spherical dust collapse have been used and continue to be used extensively to study various stellar collapse scenarios. It is by now well-known that these models lead to the formation of black holes and…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Cenalo Vaz , Louis Witten , T. P. Singh

Emergent gravity is based on a novel form of the equivalence principle known as the Darboux theorem or the Moser lemma in symplectic geometry stating that the electromagnetic force can always be eliminated by a local coordinate…

High Energy Physics - Theory · Physics 2015-02-03 Hyun Seok Yang
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