scholarly journals Global Nonlinear Stability of Schwarzschild Spacetime under Polarized Perturbations

2020 ◽  
Author(s):  
Jérémie Szeftel ◽  
Sergiu Klainerman
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Center Of Mass ◽  
Physical Reality ◽  
Affirmative Answer ◽  
Einstein Equations ◽  
Hole State ◽  
Final State ◽  
Stability Conjecture ◽  
The Stability

One of the major outstanding questions about black holes is whether they remain stable when subject to small perturbations. An affirmative answer to this question would provide strong theoretical support for the physical reality of black holes. This book takes an important step toward solving the fundamental black hole stability problem in general relativity by establishing the stability of nonrotating black holes — or Schwarzschild spacetimes — under so-called polarized perturbations. This restriction ensures that the final state of evolution is itself a Schwarzschild space. Building on the remarkable advances made in the past fifteen years in establishing quantitative linear stability, the book introduces a series of new ideas to deal with the strongly nonlinear, covariant features of the Einstein equations. Most preeminent among them is the general covariant modulation (GCM) procedure that allows them to determine the center of mass frame and the mass of the final black hole state. Essential reading for mathematicians and physicists alike, the book introduces a rich theoretical framework relevant to situations such as the full setting of the Kerr stability conjecture.

The physics of black holes I

2018 ◽  
Author(s):  
Nathalie Deruelle ◽  
Jean-Philippe Uzan
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Wave Equations ◽  
Equations Of Motion ◽  
Einstein Equations ◽  
Kerr Solution ◽  
Physical Processes ◽  
Physics Of Black Holes ◽  
Penrose Process ◽  
The Stability

This chapter describes two physical processes related to the Schwarzschild and Kerr solutions which can be induced by the gravitational field of a black hole. The first is the Penrose process, which suggests that rotating black holes are large energy reservoirs. Next is superradiance, which is the first step in the study of black-hole stability. The study of the stability of black holes involves the linearization of the Einstein equations about the Schwarzschild or Kerr solution. As this chapter shows, the equations of motion for perturbations of the metric are wave equations. The problem then is to determine whether or not these solutions are bounded.

Dynamical black holes

2020 ◽  
pp. 312-336
Author(s):  
Piotr T. Chruściel
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cauchy Data ◽  
Einstein Equations ◽  
Black Hole Spacetimes ◽  
Alternative Approaches ◽  
Definition Of ◽  
Meaningful Definition ◽  
Stability Results ◽  
Black Hole Solutions

In this chapter we review what is known about dynamical black hole-solutions of Einstein equations. We discuss the Robinson–Trautman black holes, with or without a cosmological constant. We review the Cauchy-data approach to the construction of black-hole spacetimes. We propose some alternative approaches to a meaningful definition of black hole in a dynamical spacetime, and we review the nonlinear stability results for black-hole solutions of vacuum Einstein equations.

The entropy evolution of a noncommutative black hole under Hawking radiation

2020 ◽  
Vol 35 (30) ◽  
pp. 2050194
Author(s):  
Peng Wen ◽  
Xin-Yang Wang ◽  
Wen-Biao Liu
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Hawking Radiation ◽  
New Physics ◽  
Evaporation Process ◽  
Final State ◽  
Loss Of Information ◽  
Proportion Function ◽  
Interior Volume

By calculating the entropy of a scalar field in the interior volume of noncommutative black holes and considering an infinitesimal process of Hawking radiation, a proportion function is constructed that reflects the evolution relation between the scalar field entropy and Bekenstein–Hawking entropy under Hawking radiation. Comparing with the case of Schwarzschild black holes, the new physics of this research can be expanded to the later stage of Hawking radiation. From the result, we find that the proportion function is still a constant in the earlier stage of Hawking radiation, which is identical to the case of Schwarzschild black holes. As Hawking radiation goes into the later stage, the behavior of the function will be dominated by the noncommutative effect. In this circumstance, the proportion function is no longer a constant and decreases with the evaporation process. When the noncommutative black hole evolves into its final state with Hawking radiation, the interior volume will converge to a certain value, which implies that the loss of information of the black hole during the evaporation process will finally be stored in the limited interior volume.

scholarly journals Magnetized Particle Motion around Black Holes in Conformal Gravity: Can Magnetic Interaction Mimic Spin of Black Holes?

Universe ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 44 ◽  
Author(s):  
Kamoliddin Haydarov ◽  
Ahmadjon Abdujabbarov ◽  
Javlon Rayimbaev ◽  
Bobomurat Ahmedov
Keyword(s):  
Magnetic Field ◽  
Black Holes ◽  
Black Hole ◽  
Particle Motion ◽  
Center Of Mass ◽  
Conformal Gravity ◽  
Mass Energy ◽  
Particle Collisions ◽  
Center Of Mass Energy ◽  
Sgr A

Magnetized particle motion around black holes in conformal gravity immersed in asymptotically uniform magnetic field has been studied. We have also analyzed the behavior of magnetic fields near the horizon of the black hole in conformal gravity and shown that with the increase of conformal parameters L and N the value of angular component of magnetic field at the stellar surface decreases. The maximum value of the effective potential corresponding to circular motion of the magnetized particle increases with the increase of conformal parameters. It is shown that in all cases of neutral, charged and magnetized particle collisions in the black hole environment the center-of-mass energy decreases with the increase of conformal parameters L and N. In the case of the magnetized and negatively charged particle collisions, the innermost collision point with the maximum center-of-mass energy comes closer to the central object due to the effects of the parameters of the conformal gravity. We have applied the results to the real astrophysical scenario when a pulsar treated as a magnetized particle is orbiting the super massive black hole (SMBH) Sgr A* in the center of our galaxy in order to obtain the estimation of magnetized compact object’s orbital parameter. The possible detection of pulsar in Sgr A* close environment can provide constraints on black hole parameters. Here we have shown that there is degeneracy between spin of SMBH and ambient magnetic field and consequently the interaction of magnetic field ∼ 10 2 Gauss with magnetic moment of magnetized neutron star can in principle mimic spin of Kerr black holes up to 0.6 .

scholarly journals A CONFORMAL AFFINE TODA MODEL OF 2D BLACK HOLES: A QUANTUM STUDY OF THE EVAPORATION END POINT

1993 ◽  
Vol 08 (27) ◽  
pp. 2593-2605
Author(s):  
F. BELGIORNO ◽  
A.S. CATTANEO ◽  
F. FUCITO ◽  
M. MARTELLINI
Keyword(s):  
Field Theory ◽  
Black Holes ◽  
Black Hole ◽  
Group Analysis ◽  
Black Hole Thermodynamics ◽  
Dilaton Gravity ◽  
Final State ◽  
Renormalization Group Analysis ◽  
Conformal Field ◽  
Toda Model

In this paper we reformulate the dilaton-gravity theory of Callan et al. as a new effective conformal field theory which turns out to be a generalization of the so-called SL 2-conformal affine Toda (CAT) theory studied some time ago by Babelon and Bonora. We quantize this model, thus keeping in account the dilaton-gravity quantum effects. We then implement a Renormalization Group analysis to study the black hole thermodynamics and the final state of the Hawking evaporation.

scholarly journals Remarks on regular black holes

2018 ◽  
Vol 15 (02) ◽  
pp. 1850018 ◽  
Author(s):  
Piero Nicolini ◽  
Anais Smailagic ◽  
Euro Spallucci
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Einstein Equations ◽  
Curvature Singularity ◽  
Physical Content ◽  
Regular Black Hole ◽  
Regular Black Holes ◽  
Black Hole Solutions

Recently, it has been claimed by Chinaglia and Zerbini that the curvature singularity is present even in the so-called regular black hole solutions of the Einstein equations. In this brief note, we show that this criticism is devoid of any physical content.

scholarly journals Gauge dependence and self-force from Galilean to Einsteinian free fall, compact stars falling into black holes, Hawking radiation and the Pisa tower at the general relativity centennial

2016 ◽  
Vol 13 (08) ◽  
pp. 1630014 ◽  
Author(s):  
Alessandro D. A. M. Spallicci ◽  
Maurice H. P. M. van Putten
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Undergraduate Students ◽  
Hawking Radiation ◽  
Mass Formula ◽  
Center Of Mass ◽  
Free Fall ◽  
Compact Stars ◽  
Self Force

Obviously, in Galilean physics, the universality of free fall implies an inertial frame, which in turns implies that the mass [Formula: see text] of the falling body is omitted (because it is a test mass; put otherwise, the center of mass of the system coincides with the center of the main, and fixed, mass [Formula: see text]; or else, we consider only a homogeneous gravitational field). Conversely, an additional (in the opposite or same direction) acceleration proportional to [Formula: see text] would rise either for an observer at the center of mass of the system, or for an observer at a fixed distance from the center of mass of [Formula: see text]. These elementary, but overlooked, considerations fully respect the equivalence principle (EP) and the (local) identity of an inertial or a gravitational pull for an observer in the Einstein cabin. They value as fore-runners of the self-force and gauge dependency in general relativity. Because of its importance in teaching and in the history of physics, coupled to the introductory role to Einstein’s EP, the approximate nature of Galilei’s law of free fall is explored herein. When stepping into general relativity, we report how the geodesic free fall into a black hole was the subject of an intense debate again centered on coordinate choice. Later, we describe how the infalling mass and the emitted gravitational radiation affect the free fall motion of a body. The general relativistic self-force might be dealt with to perfectly fit into a geodesic conception of motion. Then, embracing quantum mechanics, real black holes are not classical static objects any longer. Free fall has to handle the Hawking radiation, and leads us to new perspectives on the varying mass of the evaporating black hole and on the varying energy of the falling mass. Along the paper, we also estimate our findings for ordinary masses being dropped from a Galilean or Einsteinian Pisa-like tower with respect to the current state of the art drawn from precise measurements in ground and space laboratories, and to the constraints posed by quantum measurements. Appendix A describes how education physics and high impact factor journals discuss the free fall. Finally, case studies conducted on undergraduate students and teachers are reviewed.

scholarly journals Schrödinger's cat and the firewall

2014 ◽  
Vol 23 (12) ◽  
pp. 1441004 ◽  
Author(s):  
Timothy J. Hollowood
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
State Vector ◽  
High Energy ◽  
Quantum Systems ◽  
Hole State

It has been argued that when black holes are treated as quantum systems there are implications at the horizon and not just the singularity. Infalling observers will meet a firewall of high energy quanta. We argue that the question of whether an observer falling into a black hole experiences a smooth horizon or a firewall is identical to the question of whether Schrödinger's cat is either in a definite state, alive or dead, or in a superposition of the two. Since experience with real macro-systems indicate the former, the black hole state vector is seen to describe a set of decoherent alternatives each with a smooth horizon and the entanglement puzzle is thereby side stepped.

Center of mass energy for charged particles in regular black holes

2014 ◽  
Vol 92 (6) ◽  
pp. 497-503 ◽  
Author(s):  
M. Sharif ◽  
Nida Haider
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Collision Energy ◽  
Center Of Mass ◽  
Charged Particles ◽  
Charge Ratio ◽  
Regular Space ◽  
Mass Energy ◽  
Regular Black Hole ◽  
Center Of Mass Energy

This paper is devoted to study the acceleration and collision of charged particles in a general regular space–time. Using angular momentum, energy, and components of four-velocity, we explore the effect of charged particles on the center of mass energy. It is found that the collision energy of charged particles (independent of both singularity as well as horizon) is greater than that of uncharged particles. This depends not only on the mass to charge ratio of the black hole but also on the charge of the particle. Finally, we evaluate the collision energy of charged particles for a regular black hole, a particular example.

scholarly journals Superradiant stability of five and six-dimensional extremal Reissner–Nordstrom black holes

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
Jia-Hui Huang ◽  
Tian-Tian Cao ◽  
Mu-Zi Zhang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Numerical Methods ◽  
Effective Potential ◽  
Scalar Perturbation ◽  
Polynomial Equations ◽  
Potential Well ◽  
Massive Scalar ◽  
Higher Dimensional ◽  
The Stability

AbstractWe revisit the superradiant stability of five and six-dimensional extremal Reissner–Nordstrom black holes under charged massive scalar perturbation with a new analytical method. In each case, it is analytically proved that the effective potential experienced by the scalar perturbation has only one maximum outside the black hole horizon and no potential well exists for the superradiance modes. So the five and six-dimensional extremal Reissner–Nordstrom black holes are superradiantly stable. The new method we developed is based on the Descartes’ rule of signs for the polynomial equations. Our result provides a complementary support of previous studies on the stability of higher dimensional extremal Reissner–Nordstrom black holes based on numerical methods.

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