scholarly journals THE TWO-DIMENSIONAL STRINGY BLACK HOLE: A NEW APPROACH AND A NEW EFFECT

1996 ◽  
Vol 11 (08) ◽  
pp. 1463-1488
Author(s):  
H.J. DE VEGA ◽  
J. RAMÍREZ MITTELBRUN ◽  
M. RAMÓN MEDRANO ◽  
N. SÁNCHEZ
Keyword(s):  
Black Hole ◽  
Physical Phenomenon ◽  
Type Equation ◽  
Scalar Particle ◽  
Conformal Anomaly ◽  
Massless Scalar ◽  
Two Dimensional ◽  
New Approach ◽  
Klein Gordon ◽  
String Propagation

The string propagation in the two-dimensional stringy black hole is investigated from a new approach. We completely solve the classical and quantum string dynamics in the Lorentzian and Euclidean regimes. In the Lorentzian case all the physics reduces to a massless scalar particle described by a Klein-Gordon type equation with a singular effective potential. The scattering matrix is found and it reproduces the results obtained by coset CFT techniques. It factorizes into two pieces: an elastic Coulombian amplitude and an absorption part. In both parts, an infinite sequence of imaginary poles in the energy appears. The generic features of string propagation in curved D-dimensional backgrounds (string stretching, fall into space-time singularities) are analyzed in the present case. A new physical phenomenon specific to the present black hole is found: the quantum renormalization of the speed of light. We find that [Formula: see text] where k is the integer in front of the WZW action. Only for k→∞ does this new effect disappear (although the conformal anomaly is present). We analyze all the classical Euclidean string solutions and exactly compute the quantum partition function. No critical Hagedorn temperature appears here.

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.

Joule–Thomson expansion and quasinormal modes of regular non-minimal magnetic black hole

2020 ◽  
Vol 35 (36) ◽  
pp. 2050298
Author(s):  
Abdul Jawad ◽  
Muhammad Yasir ◽  
Shamaila Rani
Keyword(s):  
Black Hole ◽  
Mass Formula ◽  
Quasinormal Modes ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Thomson Effect ◽  
First Order ◽  
Thermodynamical Parameters ◽  
Klein Gordon ◽  
Tortoise Coordinate

The Joule–Thomson effect and quasinormal modes (QNM) onto regular non-minimal magnetic charged black hole with a cosmological constant are being investigated. For this purpose, we extract some thermodynamical parameters such as pressure [Formula: see text] and mass [Formula: see text] in the presence of magnetic [Formula: see text] as well as electric [Formula: see text] charge. These parameters lead to inversion temperature [Formula: see text], pressure [Formula: see text] and corresponding isenthalpic curves. We introduce the tortoise coordinate and the Klein–Gordon wave equation which leads to the second-order ordinary Schrödinger equation. We find out the complex frequencies of QNMs through the massless scalar field perturbation which satisfy boundary conditions by using the first-order Wentzel–Kramers–Brillouin (WKB) technique.

scholarly journals WEYL INVARIANCE AND SPURIOUS BLACK HOLES IN TWO-DIMENSIONAL DILATON GRAVITY

1994 ◽  
Vol 09 (27) ◽  
pp. 4811-4835 ◽  
Author(s):  
TAKANORI FUJIWARA ◽  
YUJI IGARASHI ◽  
JISUKE KUBO
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Radiation ◽  
Gravity Models ◽  
Conformal Anomaly ◽  
Quantum Level ◽  
Two Dimensional ◽  
Dilaton Gravity ◽  
Matter Coupling ◽  
Weyl Invariance

In two-dimensional dilaton gravity theories, there may exist a global Weyl invariance which makes the black hole spurious. If the global invariance and the local Weyl invariance of the matter coupling are intact at the quantum level, there is no Hawking radiation. We explicitly verify the absence of anomalies in these symmetries for the model proposed by Callan, Giddings, Harvey and Strominger. The crucial observation is that the conformal anomaly can be cohomologically trivial and so not truly anomalous in such dilaton gravity models.

scholarly journals Greybody factor for a rotating black hole with quintessential energy

2020 ◽  
Vol 2020 (3) ◽  
Author(s):  
M Sharif ◽  
Qanitah Ama-Tul-Mughani
Keyword(s):  
Black Hole ◽  
Effective Potential ◽  
State Parameter ◽  
Scalar Fields ◽  
Accelerated Expansion ◽  
Massless Scalar ◽  
Emission Rates ◽  
Rotating Black Hole ◽  
Klein Gordon ◽  
Tortoise Coordinate

Abstract This paper is devoted to deriving an analytic expression of the greybody factor for a rotating black hole surrounded by quintessence. Primarily, we transform the radial part of the Klein–Gordon equation into the standard Schrödinger equation through the tortoise coordinate to analyze the profile of the effective potential. Asymptotic solutions are obtained in two distinct regions, namely, the black hole and cosmological horizons determined by the quintessential field. We then extrapolate these solutions and match them smoothly in an intermediate region to extend the viability over the whole radial regime. To elaborate the significance of the analytical solution, we evaluate the emission rates and absorption cross-section for the massless scalar fields. It is found that the accelerated expansion of the universe corresponding to smaller values of the state parameter minimizes the effective potential and consequently increases the emission process of the scalar field particles.

Quantum gravity effect on the tunneling particles from Warped-AdS3 black hole

2018 ◽  
Vol 33 (28) ◽  
pp. 1850164 ◽  
Author(s):  
Ganim Gecim ◽  
Yusuf Sucu
Keyword(s):  
Black Hole ◽  
Angular Velocity ◽  
Black Hole Physics ◽  
Generalized Uncertainty Principle ◽  
Scalar Particle ◽  
Hawking Temperature ◽  
Dirac Equations ◽  
Inner Horizon ◽  
Quantum Gravity Effect ◽  
Klein Gordon

In this study, using the Hamilton–Jacobi approach, we investigated the Hawking temperature of the (2 + 1)-dimensional Warped-AdS3 black hole by considering the generalized uncertainty principle (GUP) effect. In this connection, we calculated quantum mechanical tunneling probabilities of the scalar spin-0 and Dirac spin-[Formula: see text] particles from the black hole by using the modified Klein–Gordon and Dirac equations, respectively. Then, we observed that the Hawking temperature of the black hole depends not only on radius and angular velocity of the outer horizon of the black hole, but also on the angular velocity of the inner horizon of the black hole and the total angular momentum, energy and mass of a tunneling particle. In this case, the Hawking radiation of Dirac particle is different from that of the scalar particle. Moreover, this situation shows that the Hawking temperature calculated under the GUP may give us information about which sort of particle is tunneling. And, the direct dependence of the Hawking temperature to the inner horizon’s angular velocity makes the effect of the Chandrasekhar–Friedman–Schutz (CFS) mechanism more clear in the black hole physics.

scholarly journals HAWKING RADIATION IN THE DILATON GRAVITY WITH A NONMINIMALLY COUPLED SCALAR FIELD

1999 ◽  
Vol 08 (06) ◽  
pp. 687-694 ◽  
Author(s):  
M. ALVES
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
External Field ◽  
Effective Mass ◽  
Hawking Radiation ◽  
Recent Literature ◽  
Additional Term ◽  
Conformal Anomaly ◽  
Two Dimensional ◽  
Dilaton Gravity

We discuss the two-dimensional dilaton gravity with a scalar field as the source matter where the coupling with gravity is given, besides the minimal one, trough an external field. This coupling generalizes the conformal anomaly in the same way as those found in recent literature, but with a different motivation. The modification to the Hawking radiation is calculated explicitly and show an additional term that introduces a dependence on the (effective) mass of the black-hole.

ON THE WHEELER-DEWITT EQUATION FOR BLACK HOLES

1994 ◽  
Vol 03 (03) ◽  
pp. 579-591 ◽  
Author(s):  
M.D. POLLOCK
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Schrödinger Equation ◽  
Schrodinger Equation ◽  
Apparent Horizon ◽  
Hamiltonian Formalism ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Two Dimensional ◽  
Superstring Theory

Integration over the angular coordinates of the evaporating, four-dimensional Schwarzschild black hole leads to a two-dimensional action, for which the Wheeler-DeWitt equation has been found by Tomimatsu, on the apparent horizon, where the Vaidya metric is valid, using the Hamiltonian formalism of Hajicek. For the Einstein theory of gravity coupled to a massless scalar field ζ, the wave function Ψ obeys the Schrödinger equation [Formula: see text], where M is the mass of the hole. The solution is [Formula: see text], where k2 is the separation constant, and for k2>0 the hole evaporates at the rate Ṁ=−k2/4M2, in agreement with the result of Hawking. Here, this analysis is generalized to the two-dimensional theory [Formula: see text], which subsumes the spherical black holes formulated in D≥4 dimensions, when A = ½ (D - 2) (D - 3)ϕ2 (D - 4)/(D - 2), B=2(D−3)/(D−2), C=1, and also the twodimensional black hole identified by Witten and by Gautam et al., when A=4/α′, B=2, C=1/8π, c=+8/α′ being (minus) the central charge. In all cases an analogous Schrödinger equation is obtained. The evaporation rate is [Formula: see text] when D≥4 and [Formula: see text] when D=2. Since Ψ evolves without violation of unitarity, there is no loss of information during the evaporation process, in accord with the principle of black-hole complementarity introduced by Susskind et al. Finally, comparison with the four-dimensional, cosmological Schrödinger equation, obtained by reduction of the ten-dimensional heterotic superstring theory including terms [Formula: see text], shows in both cases that there is a positive semi-definite potential which evolves to zero, this corresponding to the ground state, which is Minkowski space.

THE TWO-DIMENSIONAL STRINGY BLACK-HOLE: A NEW APPROACH AND A NEW EFFECT

1998 ◽  
pp. 301-332
Author(s):  
H.J. De Vega ◽  
J. Ramírez Mittelbrun ◽  
M. Ramón Medrano ◽  
N. Sánchez
Keyword(s):  
Black Hole ◽  
Two Dimensional ◽  
New Approach

scholarly journals MATRIX MODELS AND NON-PERTURBATIVE STRING PROPAGATION IN TWO-DIMENSIONAL BLACK HOLE BACKGROUNDS

1993 ◽  
Vol 08 (14) ◽  
pp. 1331-1341 ◽  
Author(s):  
SUMIT R. DAS
Keyword(s):  
Black Hole ◽  
Wave Function ◽  
String Theory ◽  
Matrix Models ◽  
Matrix Model ◽  
Asymptotic Region ◽  
Two Dimensional ◽  
White Hole ◽  
Dimensional Black Hole ◽  
String Propagation

We identify a quantity in the c = 1 matrix model which describes the wave function for physical scattering of a tachyon from a black hole of the two-dimensional critical string theory. At the semiclassical level this quantity corresponds to the usual picture of a wave coming in from infinity, part of which enters the black hole becoming singular at the singularity, while the rest is scattered back to infinity, with nothing emerging from the white hole. We find, however, that the exact non-perturbative wave function is non-singular at the singularity and appears to end up in the asymptotic region "behind" the singularity.

scholarly journals Quasinormal Frequencies of a Two-Dimensional Asymptotically Anti-de Sitter Black Hole of the Dilaton Gravity Theory

2021 ◽  
Vol 8 ◽  
Author(s):  
M. I. Hernández-Velázquez ◽  
A. López-Ortega
Keyword(s):  
Black Hole ◽  
Differential Equations ◽  
Iteration Method ◽  
Gravity Theory ◽  
Asymptotic Iteration Method ◽  
Two Dimensional ◽  
Dilaton Gravity ◽  
De Sitter ◽  
Second Order Differential Equations ◽  
Klein Gordon

We numerically calculate the quasinormal frequencies of the Klein-Gordon and Dirac fields propagating in a two-dimensional asymptotically anti-de Sitter black hole of the dilaton gravity theory. For the Klein-Gordon field we use the Horowitz-Hubeny method and the asymptotic iteration method for second order differential equations. For the Dirac field we first exploit the Horowitz-Hubeny method. As a second method, instead of using the asymptotic iteration method for second order differential equations, we propose to take as a basis its formulation for coupled systems of first order differential equations. For the two fields we find that the results that produce the two numerical methods are consistent. Furthermore for both fields we obtain that their quasinormal modes are stable and we compare their quasinormal frequencies to analyze whether their spectra are isospectral. Finally we discuss the main results.

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