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We attempt to study three significant tests of general relativity in higher dimensions both in commutative and non-commutative spaces. In the context of non-commutative geometry, we will consider a solution of the Einstein equation in…

General Relativity and Quantum Cosmology · Physics 2021-05-04 Davood Mahdavian Yekta , S. A. Alavi , Majid Karimabadi

We find a plethora of new analytic black holes and globally regular horizonless spacetimes in three dimensions. The solutions involve a single real scalar field $\phi$ which always admits a magnetic-like expression proportional to the…

General Relativity and Quantum Cosmology · Physics 2021-07-07 Pablo Bueno , Pablo A. Cano , Javier Moreno , Guido van der Velde

The Painlev\'e-Gullstrand coordinates allow us to explore the interior of the regular Hayward black hole. The behavior of an infalling particle in traversing the Hayward black hole is compared with the one inside the Schwarzschild and…

General Relativity and Quantum Cosmology · Physics 2018-05-30 Ivan Perez-Roman , Nora Bretón

Recent results show that important singularities in General Relativity can be naturally described in terms of finite and invariant canonical geometric objects. Consequently, one can write field equations which are equivalent to Einstein's…

General Relativity and Quantum Cosmology · Physics 2014-03-06 Ovidiu Cristinel Stoica

We present a nontrivial extension of the problem of spherical accretion of a collisionless kinetic gas into the standard Schwarzschild black hole. This extension consists of replacing the Schwarzschild black hole by generic static and…

General Relativity and Quantum Cosmology · Physics 2025-09-08 Mehrab Momennia , Olivier Sarbach

We use a numerical code to consider the nonlinear processes arising when a Reissner-Nordstrom black hole is irradiated by an exotic scalar field (modelled as a free massless scalar field with an opposite sign for its energy-momentum…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Andrey Doroshkevich , Jakob Hansen , Dmitriy Novikov , Igor Novikov , Dong-Ho Park , Alexander Shatskiy

Black holes are among the most fascinating objects populating our universe. Their characteristic features, encompassing spacetime singularities, event horizons, and black hole thermodynamics, provide a rich testing ground for quantum…

High Energy Physics - Theory · Physics 2016-02-23 Frank Saueressig , Natalia Alkofer , Giulio D'Odorico , Francesca Vidotto

We consider quantum effects of gravitational and electromagnetic fields in spherically symmetric black hole spacetimes in the asymptotic safety scenario. Introducing both the running gravitational and electromagnetic couplings from the…

High Energy Physics - Theory · Physics 2021-09-22 Akihiro Ishibashi , Nobuyoshi Ohta , Daiki Yamaguchi

We show that Zwei-Dreibein Gravity (ZDG), a bigravity theory recently proposed by Bergshoeff, de Haan, Hohm, Merbis, and Townsend in Phys.Rev.Lett. 111 (2013) 111102, admits exact solutions with anisotropic scale invariance. These type of…

High Energy Physics - Theory · Physics 2014-10-02 Andrés F. Goya

Employing higher curvature corrections to Einstein--Maxwell gravity has garnered a great deal of attention motivated by the high energy regime in quantum nature of black hole physics. In addition, one may employ gravity's rainbow to encode…

High Energy Physics - Theory · Physics 2018-04-30 S. H. Hendi , H. Behnamifard , B. Bahrami-Asl

In the paper, only Static Spherically Symmetric space-times in four dimensions are considered within modified gravity models. The non-singular static metrics, including black holes not admitting a de Sitter core in the center and…

General Relativity and Quantum Cosmology · Physics 2024-10-07 A. S. Agrawal , Sergio Zerbini , B. Mishra

In general, the field equation of $f(R)$ gravitational theory is very intricate, and therefore, it is not an easy task to derive analytical solutions. We consider rotating black hole spacetime four-dimensional in the $f(R)$ gravitational…

General Relativity and Quantum Cosmology · Physics 2023-06-14 G. L. N. Nashed , Shin'ichi Nojiri

The Bardeen solution corresponding to Einstein field equations with a cosmological constant is a regular black hole. The main goal of this manuscript is to investigate the geometric structures in terms of curvature conditions admitted by…

Differential Geometry · Mathematics 2022-07-15 Absos Ali Shaikh , Shyamal Kumar Hui , Mousumi Sarkar

Most of the X-ray emission from luminous accreting black holes emerges from within 20 gravitational radii. The effective emission radius is several times smaller if the black hole is rapidly spinning. General Relativistic effects can then…

High Energy Astrophysical Phenomena · Physics 2015-06-12 A. C. Fabian

We implement a Markov Chain Monte Carlo method to obtain posterior probability distributions for the parameters of the S2 star orbit around Sagittarius A*, for seven representative non-rotating black hole space-time solutions. In…

High Energy Astrophysical Phenomena · Physics 2026-02-10 César Navarrete , Fernando Vázquez-Chávez , Alejandro Cruz-Osorio , Néstor Ortiz

The so-called black bounce mechanism of singularity suppression, proposed by Simpson and Visser, consists in replacing the spherical radius $r$ in the metric tensor with $\sqrt{r^2 + a^2}$, $a = \rm const >0$. This removes a singularity at…

General Relativity and Quantum Cosmology · Physics 2024-04-29 Kirill A. Bronnikov

After a brief summary of the basic properties of stationary spacetimes representing rotating, charged black holes in strong axisymmetric magnetic fields, we concentrate on extremal cases, for which the horizon surface gravity vanishes. We…

General Relativity and Quantum Cosmology · Physics 2015-11-06 Jiří Bičák , Filip Hejda

In this letter, we investigate the strong gravitational lensing effects around two classes of rotating regular black holes, which behave as non-singular Minkowski core at the center. Starting from the null geodesic in the equatorial plane…

General Relativity and Quantum Cosmology · Physics 2025-01-07 Mingyu Guo , Menghe Wu , Hong Guo , Xiaomei Kuang , Fuyao Liu

We present a review on Lagrangian models admitting spherically symmetric regular black holes, and cosmological bounce solutions. Non-linear electrodynamics, non-polynomial gravity, and fluid approaches are explained in details. They consist…

General Relativity and Quantum Cosmology · Physics 2018-02-28 Aimeric Colléaux , Stefano Chinaglia , Sergio Zerbini

We analyze the effects of noncommutativity on phantom Reissner-Nordstr\"om-Anti-de Sitter black holes by modeling mass and charge distributions with Lorentzian profiles. The modified metric function exhibits significant deviations from the…

High Energy Physics - Theory · Physics 2025-03-20 B. Hamil , B. C. Lütfüoğlu