scholarly journals The progress of mini black holes: principles and analytical astronomical observation techniques

2021 ◽  
Vol 2083 (2) ◽  
pp. 022040
Author(s):  
Jiatong Tan
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Astronomical Observation ◽  
Quantum Field ◽  
Prospective Development ◽  
Stephen Hawking ◽  
Mini Black Holes ◽  
Background Models ◽  
Shed Light

Abstract Mini-black hole (MBH) is a concept first proposed by Stephen Hawking in the 1970s. Normally, exploring MBHs will enhance the understanding of quantum theory and gravity theory as well as be helpful in predicting the configuration of the early universe. Based on information retrieval, this paper summarizes the progress of MBHs and takes three major aspects: background, models, practical methods for observations, and analysis. Specifically, the descriptive equations are derived, and different models are discussed separately. These results shed light on the prospective development of quantum field theorem, general relativity, and string theory.

5. Entropy and thermodynamics of black holes

2015 ◽  
Author(s):  
Katherine Blundell
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Black Holes ◽  
Black Hole ◽  
Quantum Field ◽  
Black Hole Evaporation ◽  
Stephen Hawking ◽  
Laws Of Thermodynamics ◽  
Black Hole Information ◽  
Thermodynamics Of Black Holes

‘Entropy and thermodynamics of black holes’ considers how the laws of thermodynamics and entropy can be applied to black holes. It discusses the work of Roger Penrose, James Bardeen, Brandon Carter, and Stephen Hawking, which, using quantum mechanics and quantum field theory, has enabled these scientists to propose likely behaviour in and around black holes. The concepts of black hole evaporation and Hawking radiation are explained to show how black holes lose mass and eventually disappear. It concludes with the black hole information paradox: can the information stored in the matter that fell into the black hole ever be recovered?

scholarly journals Driven black holes: from Kolmogorov scaling to turbulent wakes

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Tomas Andrade ◽  
Christiana Pantelidou ◽  
Julian Sonner ◽  
Benjamin Withers
Keyword(s):  
Nonlinear Dynamics ◽  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Strong Field ◽  
De Sitter ◽  
Event Horizons ◽  
Binary Mergers ◽  
Tidal Deformations ◽  
Proof Of Principle

Abstract General relativity governs the nonlinear dynamics of spacetime, including black holes and their event horizons. We demonstrate that forced black hole horizons exhibit statistically steady turbulent spacetime dynamics consistent with Kolmogorov’s theory of 1941. As a proof of principle we focus on black holes in asymptotically anti-de Sitter spacetimes in a large number of dimensions, where greater analytic control is gained. We focus on cases where the effective horizon dynamics is restricted to 2+1 dimensions. We also demonstrate that tidal deformations of the horizon induce turbulent dynamics. When set in motion relative to the horizon a deformation develops a turbulent spacetime wake, indicating that turbulent spacetime dynamics may play a role in binary mergers and other strong-field phenomena.

scholarly journals Mimicking Black Holes in General Relativity

2021 ◽  
Author(s):  
Thomas Berry
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Thin Shell ◽  
Classical General Relativity ◽  
Regular Black Hole ◽  
Regular Black Holes ◽  
Traversable Wormholes ◽  
Hole Model ◽  
Linearised Stability

<p><b>The central theme of this thesis is the study and analysis of black hole mimickers. The concept of a black hole mimicker is introduced, and various mimicker spacetime models are examined within the framework of classical general relativity. The mimickers examined fall into the classes of regular black holes and traversable wormholes under spherical symmetry. The regular black holes examined can be further categorised as static spacetimes, however the traversable wormhole is allowed to have a dynamic (non-static) throat. Astrophysical observables are calculated for a recently proposed regular black hole model containing an exponential suppression of the Misner-Sharp quasi-local mass. This same regular black hole model is then used to construct a wormhole via the "cut-and-paste" technique. The resulting wormhole is then analysed within the Darmois-Israel thin-shell formalism, and a linearised stability analysis of the (dynamic) wormhole throat is undertaken. Yet another regular black hole model spacetime is proposed, extending a previous work which attempted to construct a regular black hole through a quantum "deformation" of the Schwarzschild spacetime. The resulting spacetime is again analysed within the framework of classical general relativity. </b></p><p>In addition to the study of black hole mimickers, I start with a brief overview of the theory of special relativity where a new and novel result is presented for the combination of relativistic velocities in general directions using quaternions. This is succeed by an introduction to concepts in differential geometry needed for the successive introduction to the theory of general relativity. A thorough discussion of the concept of spacetime singularities is then provided, before analysing the specific black hole mimickers discussed above.</p>

Frontiers of Quantum Black Holes

2020 ◽  
Vol 29 (11) ◽  
pp. 10-16
Author(s):  
Wontae KIM ◽  
Mu-In PARK
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Direct Detection ◽  
Occupation Number ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Quantum Radiation ◽  
Points Of View ◽  
Massless Quantum

A black hole is a theoretical prediction of Einstein’s general theory of relativity, differently from Newtonian gravity, which is a non-relativistic gravity. In recent few years, its direct detection via gravitational waves and other multi-messenger observations have made it possible to test the prediction and hence its associated general relativity. From purely theoretical points of view, general relativity cannot be a complete description due to its not being compatible with quantum mechanics, which is a successful description of microscopic objects. In this article, we introduce the conceptional development of quantum-gravity theories and give brief sketches of fundamental problems in quantum black holes. As an interesting model of quantum black holes, we consider a collapsing shell of matter to form a Hayward black hole and investigate semiclassically quantum radiation from the shell. By using the Israel’s formulation and the functional Schrödinger formulation for massless quantum radiation, we find that the Hawking temperature can be deduced from the occupation number of excited states when the shell approaches its own horizon.

A ROBUST TEST OF GENERAL RELATIVITY IN SPACE

2007 ◽  
Vol 16 (12a) ◽  
pp. 2319-2324 ◽  
Author(s):  
JAMES GRABER
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Quadrupole Moment ◽  
Binary Systems ◽  
High Mass ◽  
Uniqueness Theorems ◽  
Mass Ratio ◽  
Intermediate Mass ◽  
Robust Test

LISA may make it possible to test the black-hole uniqueness theorems of general relativity, also called the no-hair theorems, by Ryan's method of detecting the quadrupole moment of a black hole using high-mass-ratio inspirals. This test can be performed more robustly by observing inspirals in earlier stages, where the simplifications used in making inspiral predictions by the perturbative and post-Newtonian methods are more nearly correct. Current concepts for future missions such as DECIGO and BBO would allow even more stringent tests by this same method. Recently discovered evidence supports the existence of intermediate-mass black holes (IMBHs). Inspirals of binary systems with one IMBH and one stellar-mass black hole would fall into the frequency band of proposed maximum sensitivity for DECIGO and BBO. This would enable us to perform the Ryan test more precisely and more robustly. We explain why tests based on observations earlier in the inspiral are more robust and provide preliminary estimates of possible optimal future observations.

scholarly journals Thermodynamics of black holes in Rastall gravity

2018 ◽  
Vol 27 (07) ◽  
pp. 1850069 ◽  
Author(s):  
Iarley P. Lobo ◽  
H. Moradpour ◽  
J. P. Morais Graça ◽  
I. G. Salako
Keyword(s):  
Black Holes ◽  
Heat Capacity ◽  
General Relativity ◽  
Black Hole ◽  
Momentum Conservation ◽  
Thermodynamic Quantities ◽  
Horizon Radius ◽  
Thermodynamics Of Black Holes ◽  
Matter Fields ◽  
Energy Momentum Conservation

A promising theory in modifying general relativity (GR) by violating the ordinary energy–momentum conservation law in curved spacetime is the Rastall theory of gravity. In this theory, geometry and matter fields are coupled to each other in a nonminimal way. Here, we study thermodynamic properties of some black hole (BH) solutions in this framework, and compare our results with those of GR. We demonstrate how the presence of these matter sources amplifies the effects caused by the Rastall parameter in thermodynamic quantities. Our investigation also shows that BHs with radius smaller than a certain amount ([Formula: see text]) have negative heat capacity in the Rastall framework. In fact, it is a lower bound for the possible values of horizon radius satisfied by the stable BHs.

3. Characterizing black holes

2015 ◽  
Author(s):  
Katherine Blundell
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Gravitational Field ◽  
Curved Spacetime ◽  
Remarkable Feature ◽  
Static Limit ◽  
Frame Dragging ◽  
Axis Of Rotation ◽  
Different Types

‘Characterizing black holes’ describes the two different types of black holes: Schwarzschild black holes that do not rotate and Kerr black holes that do. The only distinguishing characteristics of black holes are their mass and their spin. A remarkable feature of a spinning black hole is that the gravitational field pulls objects around the black hole’s axis of rotation, not merely in towards its centre—an effect called frame dragging. The static limit and ergosphere regions of black holes are also described. Einstein’s equations of General Relativity allow many different solutions describing alternative versions of curved spacetime. Could white holes and worm holes exist in our universe?

scholarly journals Constructing black hole solutions in supergravity theories

2019 ◽  
Vol 34 (35) ◽  
pp. 1930017 ◽  
Author(s):  
Antonio Gallerati
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Supergravity Models ◽  
Detailed Analysis ◽  
Black Hole Solution ◽  
Explicit Construction ◽  
General Introduction ◽  
Supersymmetric Theories ◽  
Black Hole Solutions

We perform a detailed analysis of black hole solutions in supergravity models. After a general introduction on black holes in general relativity and supersymmetric theories, we provide a detailed description of ungauged extended supergravities and their dualities. Therefore, we analyze the general form of black hole configurations for these models, their near-horizon behavior and characteristic of the solution. An explicit construction of a black hole solution with its physical implications is given for the STU-model. The second part of this review is dedicated to gauged supergravity theories. We describe a step-by-step gauging procedure involving the embedding tensor formalism to be used to obtain a gauged model starting from an ungauged one. Finally, we analyze general black hole solutions in gauged models, providing an explicit example for the [Formula: see text], [Formula: see text] case. A brief review on special geometry is also provided, with explicit results and relations for supersymmetric black hole solutions.

scholarly journals Black Holes and Wormholes in Extended Gravity

Universe ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 25 ◽  
Author(s):  
Stanislav Alexeyev ◽  
Maxim Sendyuk
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Quantum Theory ◽  
Gravity Models ◽  
Astrophysical Data ◽  
Effective Gravity ◽  
Extended Gravity ◽  
Theory Of Gravity ◽  
Hawking Evaporation

We discuss black hole type solutions and wormhole type ones in the effective gravity models. Such models appear during the attempts to construct the quantum theory of gravity. The mentioned solutions, being, mostly, the perturbative generalisations of well-known ones in general relativity, carry out additional set of parameters and, therefore could help, for example, in the studying of the last stages of Hawking evaporation, in extracting the possibilities for the experimental or observational search and in helping to constrain by astrophysical data.

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.

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