scholarly journals Scalar fields and parametrized spherically symmetric black holes: Can one hear the shape of space-time?

2019 ◽  
Vol 100 (4) ◽  
Author(s):  
Sebastian H. Völkel ◽  
Kostas D. Kokkotas
Keyword(s):  
Black Holes ◽  
Scalar Fields ◽  
Space Time ◽  
Spherically Symmetric

NONCOMMUTATIVE D-BRANE WORLD, BLACK HOLES AND EXTRA DIMENSIONS

2009 ◽  
Vol 24 (18n19) ◽  
pp. 3571-3576 ◽  
Author(s):  
SUPRIYA KAR
Keyword(s):  
Black Holes ◽  
String Theory ◽  
Extra Dimensions ◽  
Space Time ◽  
Brane World ◽  
Spherically Symmetric ◽  
Axially Symmetric ◽  
Ordinary Space ◽  
Classical Black Holes ◽  
Type Iib String Theory

Inspired by the space-time noncommutativity on a D5-brane world, in a type IIB string theory, we explore the possibility of an emergent 4D ordinary space-time in the formalism. In particular, a curved D3-brane dynamics is worked out to obtain an axially symmetric and a spherically symmetric AdS and dS black holes. Extremal geometries are analyzed, using the noncommutative scaling. The emerging two dimensional semi-classical black holes are investigated to yield evidence for extra dimensions in the curved brane-world. Interestingly, a tunneling between dS to AdS vacua in the formalism is briefly discussed by incorporating the Hagedorn transitions in string theory.

AN ANSWER TO THE MAIN BLACK HOLE PATHOLOGY: FORMING NONSINGULAR BLACK HOLES FROM DUST COLLAPSE

2009 ◽  
Vol 18 (14) ◽  
pp. 2221-2229 ◽  
Author(s):  
R. MAIER ◽  
I. DAMIÃO SOARES
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Event Horizon ◽  
Nonlinear Resonance ◽  
Space Time ◽  
Low Energy ◽  
Spherically Symmetric ◽  
Energy Limit ◽  
Exterior Space

The dynamics of gravitational collapse is examined in the realm of string-based formalism of D-branes which encompasses general relativity as a low energy limit. A complete analytical solution is given to the spherically symmetric collapse of a pure dust star, including its matching with a corrected Schwarzschild exterior space–time. The collapse forms a black hole (an exterior event horizon) enclosing not a singularity but perpetually bouncing matter in the infinite chain of space–time maximal analytical extensions inside the outer event horizon. This chain of analytical extensions has a structure analogous to that of the Reissner–Nordstrom solution. The interior trapped bouncing matter has the possibility of being expelled by disruptive nonlinear resonance mechanisms.

scholarly journals Quasi-black holes: General features and purely field configurations

2015 ◽  
Vol 30 (30) ◽  
pp. 1550154 ◽  
Author(s):  
K. A. Bronnikov ◽  
O. B. Zaslavskii
Keyword(s):  
Black Holes ◽  
Small Parameter ◽  
Exact Solutions ◽  
Scalar Fields ◽  
Spherically Symmetric ◽  
Material Source

Objects that are on the threshold of forming the horizon but never collapse are called quasi-black holes (QBHs). We discuss the properties of the general spherically symmetric QBH metric without addressing its material source, including its limiting cases as the corresponding small parameter tends to zero. We then show that QBHs can exist among self-gravitating configurations of electromagnetic and dilatonic scalar fields without matter. These general results are illustrated by explicit examples of exact solutions.

scholarly journals Asymptotic quasinormal modes of string-theoretical d-dimensional black holes

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Filipe Moura ◽  
João Rodrigues
Keyword(s):  
Differential Equation ◽  
Black Holes ◽  
Complex Plane ◽  
Quasinormal Modes ◽  
Scalar Fields ◽  
Einstein Gravity ◽  
Quasinormal Mode ◽  
Spherically Symmetric ◽  
Gravitational Perturbations

Abstract We compute the quasinormal frequencies of d-dimensional spherically symmetric black holes with leading string α′ corrections for tensorial gravitational perturbations in the highly damped regime. We solve perturbatively the master differential equation and we compute the monodromies of the master perturbation variable (analytically continued to the complex plane) in different contours, in order to obtain the quasinormal mode spectra. We proceed analogously for the quasinormal modes of test scalar fields. Differently than in Einstein gravity, we obtain distinct results for the two cases.

BLACK HOLES AND WORMHOLES IN RS2 TYPE BRANE WORLDS

2005 ◽  
Vol 20 (11) ◽  
pp. 2256-2264 ◽  
Author(s):  
K. A. BRONNIKOV ◽  
A. V. MICHTCHENKO
Keyword(s):  
Black Holes ◽  
Strong Field ◽  
Scalar Fields ◽  
Spherically Symmetric ◽  
Field Region ◽  
Field Equations ◽  
Black String ◽  
Brane Worlds ◽  
Gravity Equations ◽  
Extremal Black Holes

We review some recent results concerning the properties of static, spherically symmetric configurations in RS2 type brane worlds: 1) Solving the trace of the effective 4D gravity equations, we obtain general classes of black hole and wormhole metrics, including families which unify symmetric wormholes, extremal black holes and non-extremal non-singular black holes. 2) Assuming [Formula: see text] (where [Formula: see text] is a part of the 5D Weyl tensor contributing to the 4D gravity equations), we show that material scalar fields confined on the brane may violate the no-hair theorem, support wormholes or form particlelike objects, but only at super-nuclear matter densities in the strong field region. 3) Solutions to the bulk field equations are found in case [Formula: see text], among them solutions with a nonzero 4D cosmological constant, generalizing the so-called "black string".

scholarly journals Regular Frames for Spherically Symmetric Black Holes Revisited

Symmetry ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 40
Author(s):  
Alexey V. Toporensky ◽  
Oleg B. Zaslavskii
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Specific Energy ◽  
General Scheme ◽  
Space Time ◽  
Coordinate Frame ◽  
Spherically Symmetric ◽  
Symmetric Black Hole

We consider a space-time of a spherically symmetric black hole with one simple horizon. As a standard coordinate frame fails in its vicinity, this requires continuation across the horizon and constructing frames which are regular there. Up to now, several standard frames of such a kind are known. It was shown in the literature before, how some of them can be united in one picture as different limits of a general scheme. However, some types of frames (the Kruskal–Szekeres and Lemaître ones) and transformations to them from the original one remained completely disjoint. We show that the Kruskal–Szekeres and Lemaître frames stem from the same root. Overall, our approach in some sense completes the procedure and gives the most general scheme. We relate the parameter of transformation e0 to the specific energy of fiducial observers and show that in the limit e0→0, a homogeneous metric under the horizon can be obtained by a smooth limiting transition.

scholarly journals Janis–Newman–Winicour and Wyman Solutions are the Same

1997 ◽  
Vol 12 (27) ◽  
pp. 4831-4835 ◽  
Author(s):  
K. S. Virbhadra
Keyword(s):  
Exact Solution ◽  
Scalar Field ◽  
Total Energy ◽  
Space Time ◽  
Massless Scalar ◽  
Spherically Symmetric ◽  
Scalar Equations

We show that the well-known most general static and spherically symmetric exact solution to the Einstein-massless scalar equations given by Wyman is the same as one found by Janis, Newman and Winicour several years ago. We obtain the energy associated with this space–time and find that the total energy for the case of the purely scalar field is zero.

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