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Applying the Hamilton--Jacobi method we investigate the tunneling of photon across the event horizon of a static spherically symmetric black hole. The necessity of the gauge condition on the photon field, to derive the semiclassical Hawking…

High Energy Physics - Theory · Physics 2010-09-06 Bibhas Ranjan Majhi , Saurav Samanta

[Abridged] Context. The Galactic Center supermassive black hole is well known to exhibit transient peaks of flux density on a daily basis across the spectrum. Recent infrared and millimeter observations have strengthened the case for the…

High Energy Astrophysical Phenomena · Physics 2023-09-20 F. H. Vincent , M. Wielgus , N. Aimar , T. Paumard , G. Perrin

This paper consists of three steps. In the first, we prove that the Bekenstein-Hawking entropy is the unique expression of black hole entropy. Our proof is constructed in the framework of thermodynamics without any statistical discussion.…

General Relativity and Quantum Cosmology · Physics 2011-09-06 Hiromi Saida

We study static and radially symmetric black holes in the multi-fractional theories of gravity with $q$-derivatives and with weighted derivatives, frameworks where the spacetime dimension varies with the probed scale and geometry is…

General Relativity and Quantum Cosmology · Physics 2017-05-26 Gianluca Calcagni , David Rodríguez Fernández , Michele Ronco

In this paper we abandon the idea that even a "quantum" black hole, of Planck size, can still be described as a classical, more or less complicated, geometry. Rather, we consider a genuine quantum mechanical approach where a Planckian black…

High Energy Physics - Theory · Physics 2017-05-26 Euro Spallucci , Anais Smailagic

Testing gravity theory in the strong field region becomes a reality due to the observations of gravitational waves and black hole shadows. In this paper, we discuss how to constrain the possible deviations of the classical general…

General Relativity and Quantum Cosmology · Physics 2019-09-10 S. X. Tian , Zong-Hong Zhu

We discuss some of the drawbacks of using event horizons to define black holes and suggest ways in which black holes can be described without event horizons, using trapping horizons. We show that these trapping horizons give rise to…

General Relativity and Quantum Cosmology · Physics 2009-03-20 Alex B. Nielsen

We discuss a new class of solutions to the Einstein equations which describe a primordial black hole (PBH) in a flat Friedmann background. Such solutions arise if a Schwarzschild black hole is patched onto a Friedmann background via a…

Astrophysics · Physics 2008-11-26 Tomohiro Harada , B. J. Carr

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

Inspired by the recent conjecture that black holes are condensates of gravitons, we investigate a simple model for the black hole degrees of freedom that is consistent both from the point of view of Quantum mechanics and of General…

General Relativity and Quantum Cosmology · Physics 2013-10-24 Roberto Casadio , Alessio Orlandi

The many low energy modes near a black hole horizon give the thermal atmosphere a divergent entropy which becomes of order $A/4G$ with a Planck scale cut-off. However, Sorkin has given a Newtonian argument for 3+1 Schwarzschild black holes…

High Energy Physics - Theory · Physics 2008-11-26 Donald Marolf

We construct an analytic model of static semiclassical backreaction for a Schwarzschild black hole in the Hartle--Hawking state enclosed within a finite spherical cavity. Using a minimal renormalized stress--energy tensor consistent with…

General Relativity and Quantum Cosmology · Physics 2026-04-14 G. G. L. Nashed , Alnadhief H. A. Alfedeel , Tiberiu Harko

We determine coherent states peaked at classical space-time of the Schwarzschild black hole in the frame-work of canonical quantisation of general relativity. The information about the horizon is naturally encoded in the phase space…

High Energy Physics - Theory · Physics 2009-11-10 Arundhati Dasgupta

We study analytically quantum tunneling of relativistic and non-relativistic particles at both Killing and universal horizons of Einstein-Maxwell-aether black holes, after high-order curvature corrections are taken into account, for which…

General Relativity and Quantum Cosmology · Physics 2016-11-23 Chikun Ding , Anzhong Wang , Xinwen Wang , Tao Zhu

We introduce the concept of timelike entanglement entropy of Hawking radiation as a novel probe of the black hole information paradox. By analytically continuing black hole spacetimes to Euclidean signature, we define timelike correlations…

General Relativity and Quantum Cosmology · Physics 2026-02-09 Yahya Ladghami , Francisco S. N. Lobo , Taoufik Ouali

The description of a point mass in general relativity (GR) is given in the framework of the field formulation of GR where all the dynamical fields, including the gravitational field, are considered in a fixed background spacetime. With the…

General Relativity and Quantum Cosmology · Physics 2009-11-11 A. N. Petrov

For long black holes have been considered as endowed with a definite temperature. Yet when the Schwarzschild black hole is treated as a canonical ensemble three problems arise: incompatibility with the Hawking radiation, divergence of the…

General Relativity and Quantum Cosmology · Physics 2009-12-30 Gilad Gour

The main goal of this thesis is to study the gravitational action for the Schwarzschild black hole and its subsequent regularisation from the perspective of general relativity and teleparallel gravity. The standard approach of general…

General Relativity and Quantum Cosmology · Physics 2025-03-18 Michal Stano

We consider a simple model for a black-hole laser: a Bose-Einstein condensate with uniform speed of sound and partially uniform flow, establishing two horizons, a black-hole and a white-hole horizon. Waves confined between the horizons are…

General Relativity and Quantum Cosmology · Physics 2019-01-09 David Bermudez , Ulf Leonhardt

We investigate the black hole information paradox in the setting of pseudo-complex gravity, a covariant geometric extension of general relativity that introduces a minimal length scale by deforming the spacetime manifold. In this framework,…

General Relativity and Quantum Cosmology · Physics 2025-06-30 Fridolin Weberand Peter O. Hess , Cesar A. Zen Vasconcellos