Related papers: Are black holes totally black?
This paper is devoted to the study of particles collision for two well-known black holes. We consider particles moving in equatorial plane and calculate their center of mass energy. Firstly, we explore center of mass energy of a regular…
We argue the existence of solutions of the Euclidean Einstein equations that correspond to a vortex sitting at the horizon of a black hole. We find the asymptotic behaviours, at the horizon and at infinity, of vortex solutions for the gauge…
Black holes are the densest form of energy, and in the presence of compact dimensions black objects may take one of several forms including the black-hole and the black-string, the simplest relevant background being R^{3+1} * S^1. Recent…
The possibility that rotating black holes could be natural particle accelerators has been subject of intense debate. While it appears that for extremal Kerr black holes arbitrarily high center of mass energies could be achieved, several…
It has recently been pointed out that particles falling freely from rest at infinity outside a Kerr black hole can in principle collide with arbitrarily high center of mass energy in the limiting case of maximal black hole spin. Here we aim…
The geodesic equations are considered in static mass imbedded in a uniform electromagnetic field. Due to electromagnetic field horizon shrinks and geodesics are modified. By analyzing the behavior of the effective potentials for the…
The increasing data set of precise observations of very energetic and collimated jets, with black hole (BH) as putative central engine, at different astrophysical scales and in various environments, should soon permit to discriminate and…
Based on the idea that tensor unparticles can enhance the gravitational interactions between standard model particles, potential black hole formation in high energy collisions is examined. Modifications to the horizon radius $r_H$ are…
We study the geodesic motion of massive and massless test particles in the background of a particular class of multiple charge black holes in gauged supergravity theories in D = 4. We have analysed the horizon structure along with the…
The entropy of charged black hole is calculated by using the partition function evaluated at radial geodesics confined under horizons. We establish two quantum phase states inside the black hole and a transition between them.
General relativity predicts that the Kerr black hole develops qualitatively new and surprising features in the limit of maximal spin. Most strikingly, the region of spacetime near the event horizon stretches into an infinitely long throat…
We consider collision of two particles near static electrically charged extremal black holes and elucidate the conditions under which the energy in the centre of mass frame E_{c.m.} grows unbounded. For a single black hole, we generalize…
In this paper, the equations of motion for geodesics in the neutral rotating Black Ring metric are derived and the separability of these equations is considered. The bulk of the paper is concerned with sets of solutions where the geodesic…
The role of the wandering null geodesic is studied in a black hole spacetime. Based on the continuity of the solution of the geodesic equation, the wandering null geodesics commonly exist and explain the typical phenomena of the optical…
Black hole solutions are studied here within the symmetric teleparallel formulation of gravity, employing the $f(Q)$ model in which the gravitational dynamics are governed by the non-metricity scalar $Q$. We focus on static, circularly…
We consider collision between two charged (or charged and neutral) particles near the black hole horizon in the strong magnetic field B. It is shown that there exists a strip near the horizon within which collision of any two such particles…
Black holes are a paradigm in nowadays physics, and are expected to be hosted at the center of galaxies. Supermassive galactic black holes are not isolated, and their surroundings play crucial roles in many observational features. The…
Current astrophysical observations show that on large scale the Universe is electrically neutral. However, locally this may be quite different. Black holes enveloped by a plasma in the presence of a strong magnetic field may have acquired a…
We specify an angular motion on geodesics to reduce the problem to the case of radial motion elaborated in previous chapters. An appropriate value of entropy for a charged and rotating black hole is obtained by calculating the partition…
Classical general relativity predicts a singularity at the center of a black hole, where known laws of physics break down. This suggests the existence of deeper, yet unknown principles of Nature. Among various theoretical possibilities, one…