scholarly journals SELF-SIMILAR COLLAPSE OF A SCALAR FIELD IN DILATON GRAVITY AND CRITICAL BEHAVIOR

2004 ◽  
Vol 19 (15) ◽  
pp. 2495-2504 ◽  
Author(s):  
STOYTCHO S. YAZADJIEV
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Critical Behavior ◽  
Analytical Models ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Black Hole Mass ◽  
General Relativistic ◽  
Self Similar ◽  
Similar Solutions

We present new analytical self-similar solutions describing a collapse of a massless scalar field in scalar–tensor theories. The solutions exhibit a type of critical behavior. The black hole mass for the near critical evolution is analytically obtained for several scalar–tensor theories and the critical exponent is calculated. Within the framework of the analytical models we consider it is found that the black hole mass law for some scalar–tensor theories is of the form M BH =f(p-p cr )(p-p cr )γ which is slightly different from the general relativistic law M BH = const (p-p cr )γ. The explicit form of the function f depends on the particular scalar–tensor theory.

scholarly journals GRAVITATIONAL COLLAPSE OF A MASSLESS SCALAR FIELD AND A PERFECT FLUID WITH SELF-SIMILARITY OF THE FIRST KIND IN 2+1 DIMENSIONS

2008 ◽  
Vol 17 (11) ◽  
pp. 2143-2158 ◽  
Author(s):  
F. I. M. PEREIRA ◽  
R. CHAN
Keyword(s):  
Black Holes ◽  
Scalar Field ◽  
Perfect Fluid ◽  
Gravitational Collapse ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Self Similarity ◽  
Global Properties ◽  
Self Similar ◽  
Similar Solutions

Self-similar solutions of a collapsing perfect fluid and a massless scalar field with kinematic self-similarity of the first kind in 2+1 dimensions are obtained. The local and global properties of the solutions are studied. It is found that some of them represent gravitational collapse, in which black holes are always formed, and some may be interpreted as representing cosmological models.

GRAVITATIONAL COLLAPSE OF A MASSLESS SCALAR FIELD AND A PERFECT FLUID WITH SELF-SIMILARITY OF THE SECOND KIND IN (2 + 1) DIMENSIONS

2006 ◽  
Vol 15 (02) ◽  
pp. 131-152 ◽  
Author(s):  
F. I. M. PEREIRA ◽  
R. CHAN ◽  
AN ZHONG WANG
Keyword(s):  
Black Holes ◽  
Scalar Field ◽  
Perfect Fluid ◽  
Gravitational Collapse ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Self Similarity ◽  
Global Properties ◽  
Self Similar ◽  
Similar Solutions

Self-similar solutions of a collapsing perfect fluid and a massless scalar field with kinematic self-similarity of the second kind in (2 + 1) dimensions are obtained. The local and global properties of the solutions are studied. It is found that some of them represent gravitational collapse, in which black holes are always formed, and some may be interpreted as representing cosmological models.

scholarly journals A (gravitational) toy story

2017 ◽  
Vol 26 (09) ◽  
pp. 1750096
Author(s):  
W. Barreto ◽  
H. P. de Oliveira ◽  
B. Rodriguez-Mueller
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Critical Exponent ◽  
Critical Behavior ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
De Sitter ◽  
Hole Formation ◽  
Black Hole Formation ◽  
Mass Gap

Frequently in Physics, insights and conclusions can be drawn from simple, idealized models. The discovery of critical behavior in the gravitational collapse of a massless scalar field leads to the simulation of binary black holes, from its coalescence to merging and ringdown. We refined a toy model to explore black hole formation as these events unfold to revisit the instability of a gravitational kink. We confirmed a conjecture related to a mass gap for critical behavior at the threshold of black hole formation. We find a critical exponent twice the standard value. Surprisingly, this larger critical exponent is also present in the multiple critical behavior for the black hole formation from a massless scalar field in asymptotically anti-de Sitter spacetimes. What is the meaning of this mass gap? Does it have physical relevance?

scholarly journals Quasi-normal modes and the area spectrum of a near extremal de Sitter black hole with conformally coupled scalar field

2015 ◽  
Vol 30 (11) ◽  
pp. 1550057 ◽  
Author(s):  
Sharmanthie Fernando
Keyword(s):  
Black Hole ◽  
Wave Equation ◽  
Scalar Field ◽  
Normal Modes ◽  
Type Equation ◽  
Area Spectrum ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
De Sitter ◽  
Quasi Normal Mode

In this paper, we have studied a black hole in de Sitter space which has a conformally coupled scalar field in the background. This black hole is also known as the MTZ black hole. We have obtained exact values for the quasi-normal mode (QNM) frequencies under massless scalar field perturbations. We have demonstrated that when the black hole is near-extremal, that the wave equation for the massless scalar field simplifies to a Schrödinger type equation with the well-known Pöschl–Teller potential. We have also used sixth-order WKB approximation to compute QNM frequencies to compare with exact values obtained via the Pöschl–Teller method for comparison. As an application, we have obtained the area spectrum using modified Hods approach and show that it is equally spaced.

scholarly journals THE REAL SCALAR FIELD EQUATION FOR NARIAI BLACK HOLE IN THE 5D SCHWARZSCHILD–DE SITTER BLACK STRING SPACE

2007 ◽  
Vol 22 (24) ◽  
pp. 4451-4465 ◽  
Author(s):  
MOLIN LIU ◽  
HONGYA LIU ◽  
CHUNXIAO WANG ◽  
YONGLI PING
Keyword(s):  
Black Hole ◽  
Field Equation ◽  
Scalar Field ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
De Sitter ◽  
Black String ◽  
Transmission Coefficients ◽  
Scalar Field Equation ◽  
Continuous Potential

The Nariai black hole, whose two horizons are lying close to each other, is an extreme and important case in the research of black hole. In this paper we study the evolution of a massless scalar field scattered around in 5D Schwarzschild–de Sitter black string space. Using the method shown by Brevik and Simonsen (2001) we solve the scalar field equation as a boundary value problem, where real boundary condition is employed. Then with convenient replacement of the 5D continuous potential by square barrier, the reflection and transmission coefficients (R, T) are obtained. At last, we also compare the coefficients with the usual 4D counterpart.

Disappearance of Black Hole Criticality in Semiclassical General Relativity

1997 ◽  
Vol 12 (10) ◽  
pp. 709-718 ◽  
Author(s):  
Takeshi Chiba ◽  
Masaru Siino
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Scalar Field ◽  
Critical Phenomena ◽  
Equations Of Motion ◽  
Quantum Effects ◽  
Hole Formation ◽  
Trace Anomaly ◽  
Self Similar ◽  
Similar Solutions

We investigate the quantum effects on the so-called critical phenomena in black hole formation. Quantum effects of a scalar field are treated semiclassically via a trace anomaly method. It is found that the demand of regularity at the origin implies the disappearance of the echo. It is also found that semiclassical equations of motion do not admit continuously self-similar solutions. The quantum effects would change the critical solution from a discretely self-similar one to a solution without critical phenomena.

scholarly journals Gravitational collapse in the AdS background and the black hole formation

2016 ◽  
Vol 25 (01) ◽  
pp. 1650005 ◽  
Author(s):  
Alireza Allahyari ◽  
Javad T. Firouzjaee ◽  
Reza Mansouri
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Event Horizon ◽  
Gravitational Collapse ◽  
Apparent Horizon ◽  
Rapid Change ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Hole Formation ◽  
Thermalization Time

We study the time evolution of the Misner-Sharp mass and the apparent horizon for gravitational collapse of a massless scalar field in the [Formula: see text] spacetime for both cases of narrow and broad waves by numerically solving the Einstein’s equations coupled to a massless scalar field. This is done by relying on the full dynamics of the collapse including the concept of the dynamical horizon. It turns out that the Misner-Sharp mass is everywhere constant except for a rapid change across a thin shell defined by the density profile of the collapsing wave. By studying the evolution of the apparent horizon, indicating the formation of a black hole at different times we see how asymptotically an event horizon forms. The dependence of the thermalization time on the radius of the initial black hole event horizon is also studied.

scholarly journals DISCUSSION ON SOME CHARACTERISTICS OF CHARGED BRANE-WORLD BLACK HOLES

2009 ◽  
Vol 24 (04) ◽  
pp. 719-739 ◽  
Author(s):  
M. KALAM ◽  
F. RAHAMAN ◽  
A. GHOSH ◽  
B. RAYCHAUDHURI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Field ◽  
Scalar Field ◽  
Brane World ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Effective Potentials ◽  
Test Particles ◽  
Jacobi Formalism

Several physical natures of charged brane-world black holes are investigated. Firstly, the timelike and null geodesics of the charged brane-world black holes are presented. We also analyze all the possible motions by plotting the effective potentials for various parameters for circular and radial geodesics. Secondly, we investigate the motion of test particles in the gravitational field of the charged brane-world black holes using the Hamilton–Jacobi formalism. We consider charged and uncharged test particles and examine their behavior in both static and nonstatic cases. Thirdly, the thermodynamics of the charged brane-world black holes are studied. Finally, it is shown that there is no phenomenon of superradiance for an incident massless scalar field for such a black hole.

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