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Related papers: Varying Constants, Black Holes, and Quantum Gravit…

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To ask a question about a black hole in quantum gravity, one must restrict initial or boundary data to ensure that a black hole is actually present. For two-dimensional dilaton gravity, and probably a much wider class of theories, I show…

High Energy Physics - Theory · Physics 2010-04-28 S. Carlip

When it comes to performing thought experiments with black holes, Einstein-Bohr like discussions have to be re-opened. For instance one can ask what happens to the quantum state of a black hole when the wave function of a single ingoing…

General Relativity and Quantum Cosmology · Physics 2007-05-23 G. 't Hooft

Along this review, we focus on the study of several properties of modified gravity theories, in particular on black-hole solutions and its comparison with those solutions in General Relativity, and on Friedmann-Lemaitre-Robertson-Walker…

General Relativity and Quantum Cosmology · Physics 2015-06-05 A. de la Cruz-Dombriz , D. Saez-Gomez

Regular black holes have become a popular alternative to the singular mathematical black holes predicted by general relativity as they circumvent mathematical pathologies associated with the singularity while preserving crucial black hole…

General Relativity and Quantum Cosmology · Physics 2024-08-15 Ioannis Soranidis

We obtain a new general solution for the gravitational field equations in quantum fluctuation modified gravity, which reduces to different classes of black holes surrounded by fluids, by taking some specific values of the parameter of the…

General Relativity and Quantum Cosmology · Physics 2026-04-14 Yaobin Hua , Rong-Jia Yang

If the fine structure constant $\alpha =e^2/(\hbar c)$ were to change, then a number of interpretations would be possible, attributing this change either to variations in the electron charge, the dielectric constant of the vacuum, the speed…

Astrophysics · Physics 2009-10-31 John D. Barrow , Joao Magueijo

Although the fundamental equations of ordinary thermodynamic systems are known to correspond to first-degree homogeneous functions, in the case of non-ordinary systems like black holes the corresponding fundamental equations are not…

General Relativity and Quantum Cosmology · Physics 2019-03-27 Hernando Quevedo , Maria N. Quevedo , Alberto Sanchez

In a recent work we have argued that nosy energy momentum diffusion due to space-time discreteness at the Planck scale (naturally expected to arise from quantum gravity) can be responsible for the generation of a cosmological constant…

General Relativity and Quantum Cosmology · Physics 2019-11-15 Alejandro Perez , Daniel Sudarsky

In this lecture, I explain the gauge-invariant formulation for perturbations of background spacetimes with untwisted homologous Einstein fibres, which include lots of practically important spacetimes such as static black holes, static black…

High Energy Physics - Theory · Physics 2009-01-28 Hideo Kodama

Several properties of canonical quantum gravity modify space-time structures, sometimes to the degree that no effective line elements exist to describe the geometry. An analysis of solutions, for instance in the context of black holes, then…

General Relativity and Quantum Cosmology · Physics 2011-11-04 Martin Bojowald , George M. Paily , Juan D. Reyes , Rakesh Tibrewala

We examine the conjecture for the complete monotonicity of certain curvature invariants for quantum black holes. In this note, we study a class of quantum regular black holes that are static, spherically symmetric, and characterized only by…

High Energy Physics - Theory · Physics 2025-09-30 A. Almasi , A. Moradpouri , M. Shahbazi

Black holes exist all over our Universe, possessing a very wide range of masses. At the moment, they serve as a probe to test general relativity at astrophysical scales, but in the future they may also give us information about gravity at…

High Energy Physics - Theory · Physics 2025-10-24 Tiago V. Fernandes

Criteria for thermal stability of charged rotating black holes of any dimension are derived, for horizon areas that are large relative to the Planck area (in these dimensions). The derivation is based on generic assumptions of quantum…

General Relativity and Quantum Cosmology · Physics 2018-07-30 Aloke Kumar Sinha , Parthasarathi Majumdar

Recently, exotic black holes whose masses and angular momenta are interchanged have been found, and it is known that their entropies depend only on the $inner$ horizon areas. But a basic problem of these entropies is that the second law of…

High Energy Physics - Theory · Physics 2008-11-26 Mu-In Park

We quantize a scalar field at finite temperature T in the background of a classical black hole, adopting 't Hooft's ``brick wall'' model with generic mixed boundary conditions at the brick wall boundary. We first focus on the exactly…

High Energy Physics - Theory · Physics 2007-05-23 Giuseppe Milanesi , Mihail Mintchev

Recently, Ho$\breve{r}$ava proposed a non-relativistic renormalizable theory of gravity which is essentially a field theoretic model for a UV complete theory of gravity and reduces to Einstein gravity with a non-vanishing cosmological…

General Relativity and Quantum Cosmology · Physics 2015-03-19 Ritabrata biswas , Subenoy Chakraborty

Black holes monopolize nowadays the center stage of fundamental physics. Yet, they are poorly understood objects. Notwithstanding, from their generic properties, one can infer important clues to what a fundamental theory, a theory that…

General Relativity and Quantum Cosmology · Physics 2008-04-05 José P. S. Lemos

By using the canonical Hamiltonian method, we obtain the mass and entropy of the black holes with general dynamical coupling constant $\lambda$ in Ho\v{r} ava-Lifshitz Gravity. Regardless of whether the horizon is sphere, plane or…

High Energy Physics - Theory · Physics 2009-09-28 Rong-Gen Cai , Li-Ming Cao , Nobuyoshi Ohta

Dynamical black-hole scenarios have been developed in loop quantum gravity in various ways, combining results from mini and midisuperspace models. In the past, the underlying geometry of space-time has often been expressed in terms of line…

General Relativity and Quantum Cosmology · Physics 2020-09-30 Martin Bojowald

We investigate spacetimes in which the speed of light along flat 4D sections varies over the extra dimensions due to different warp factors for the space and the time coordinates (``asymmetrically warped'' spacetimes). The main property of…

High Energy Physics - Theory · Physics 2008-11-26 Csaba Csaki , Joshua Erlich , Christophe Grojean