scholarly journals DYONIC BLACK HOLES WITH STRING-LOOP CORRECTIONS

2003 ◽  
Vol 18 (11) ◽  
pp. 1903-1933
Author(s):  
MIKHAIL Z. IOFA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Black Hole Solution ◽  
Low Energy ◽  
Tree Level ◽  
Coupling Constant ◽  
Heterotic String Theory ◽  
Four Dimensions ◽  
First Order ◽  
String Loop

In heterotic string theory compactified to four dimensions with N = 2 supersymmetry, string-loop corrections to the universal sector of the low-energy effective action are studied. Within the framework of N = 2 supersymmetric formulation of the theory, in the first order in string coupling constant, we solve the system of the loop-corrected Maxwell and Killing spinor equations. Taking as the input the tree-level dyonic black hole solution, we calculate string-loop corrections to the string tree-level metric and moduli of dyonic black hole.

scholarly journals N=2 SUPERSYMMETRY AND STRING-LOOP CORRECTED MAGNETIC BLACK HOLES

2002 ◽  
Vol 17 (06) ◽  
pp. 355-371 ◽  
Author(s):  
MIKHAIL Z. IOFA
Keyword(s):  
Black Hole ◽  
Maxwell Equations ◽  
Black Hole Solution ◽  
Equations Of Motion ◽  
Level Gauge ◽  
Tree Level ◽  
Loop Correction ◽  
Heterotic String Theory ◽  
String Loop ◽  
Gauge Couplings

We study string-loop corrections to magnetic black hole. Four-dimensional theory is obtained by compactification of the heterotic string theory on the manifold K3×T2 or on a suitable orbifold yielding N=1 supersymmetry in 6D. The resulting 4D theory has N=2 local supersymmetry. Prepotential of this theory receives only one-string-loop correction. The tree-level gauge couplings are proportional to the inverse effective string coupling and decrease at small distances from the center of magnetic black hole, so that loop corrections to the gauge couplings are important in this region. We solve the system of Killing spinor equations (conditions for the supersymmetry variations of the fermions to vanish) and Maxwell equations. At the string-tree level, we reproduce the magnetic black hole solution which can also be obtained by solving the system of the Einstein–Maxwell equations and the equations of motion for the moduli. String-loop corrections to the tree-level solution are calculated in the first order in string coupling. The resulting corrections to the metric and dilaton are large at small distances from the center of the black hole. Possible smearing of the singularity at the origin by quantum corrections is discussed.

scholarly journals Islands and Page curves of Reissner-Nordström black holes

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Xuanhua Wang ◽  
Ran Li ◽  
Jin Wang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Radiation ◽  
Entanglement Entropy ◽  
Additional Term ◽  
Current Case ◽  
Information Paradox ◽  
Extremal Surface ◽  
Four Dimensions ◽  
Black Hole Information

Abstract We apply the recently proposed quantum extremal surface construction to calculate the Page curve of the eternal Reissner-Nordström black holes in four dimensions ignoring the backreaction and the greybody factor. Without the island, the entropy of Hawking radiation grows linearly with time, which results in the information paradox for the eternal black holes. By extremizing the generalized entropy that allows the contributions from the island, we find that the island extends to the outside the horizon of the Reissner-Nordström black hole. When taking the effect of the islands into account, it is shown that the entanglement entropy of Hawking radiation at late times for a given region far from the black hole horizon reproduces the Bekenstein-Hawking entropy of the Reissner-Nordström black hole with an additional term representing the effect of the matter fields. The result is consistent with the finiteness of the entanglement entropy for the radiation from an eternal black hole. This facilitates to address the black hole information paradox issue in the current case under the above-mentioned approximations.

scholarly journals EXTREMAL BLACK HOLES AND ELEMENTARY STRING STATES

1995 ◽  
Vol 10 (28) ◽  
pp. 2081-2093 ◽  
Author(s):  
ASHOKE SEN
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Black Hole Entropy ◽  
Extremal Black Hole ◽  
Coupling Constant ◽  
Left Handed ◽  
Quantum Numbers ◽  
Independent Parameters ◽  
Elementary String ◽  
Extremal Black Holes

Some of the extremal black hole solutions in string theory have the same quantum numbers as the Bogomol’nyi saturated elementary string states. We explore the possibility that these black holes can be identified with elementary string excitations. It is shown that stringy effects could correct the Bekenstein-Hawking formula for the black hole entropy in such a way that it correctly reproduces the logarithm of the density of elementary string states. In particular, this entropy has the correct dependence on three independent parameters, the mass and the left-handed charge of the black hole, and the string coupling constant.

scholarly journals Massive scalar field perturbation on Kerr black holes in dynamical Chern–Simons gravity

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Shao-Jun Zhang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Massive Scalar ◽  
Coupling Constant ◽  
Field Mass ◽  
Field Perturbation ◽  
Massive Scalar Field ◽  
Kerr Black Holes ◽  
Chern Simons

AbstractWe study massive scalar field perturbation on Kerr black holes in dynamical Chern–Simons gravity by performing a $$(2+1)$$ ( 2 + 1 ) -dimensional simulation. Object pictures of the wave dynamics in time domain are obtained. The tachyonic instability is found to always occur for any nonzero black hole spin and any scalar field mass as long as the coupling constant exceeds a critical value. The presence of the mass term suppresses or even quench the instability. The quantitative dependence of the onset of the tachyonic instability on the coupling constant, the scalar field mass and the black hole spin is given numerically.

scholarly journals Causality of black holes in 4-dimensional Einstein–Gauss–Bonnet–Maxwell theory

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Xian-Hui Ge ◽  
Sang-Jin Sin
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Shear Viscosity ◽  
Upper Bound ◽  
Causal Structure ◽  
Density Ratio ◽  
Entropy Density ◽  
Coupling Constant ◽  
Maxwell Theory ◽  
Black Hole Solutions

Abstract We study charged black hole solutions in 4-dimensional (4D) Einstein–Gauss–Bonnet–Maxwell theory to the linearized perturbation level. We first compute the shear viscosity to entropy density ratio. We then demonstrate how bulk causal structure analysis imposes an upper bound on the Gauss–Bonnet coupling constant in the AdS space. Causality constrains the value of Gauss–Bonnet coupling constant $$\alpha _{GB}$$αGB to be bounded by $$\alpha _{GB}\le 0$$αGB≤0 as $$D\rightarrow 4$$D→4.

scholarly journals STRING-LOOP CORRECTIONS TO EFFECTIVE ACTION AND BLACK HOLE INSTABILITIES

1995 ◽  
Vol 10 (07) ◽  
pp. 575-585
Author(s):  
V. V. BELOKUROV ◽  
M. Z. IOFA
Keyword(s):  
Black Hole ◽  
String Theory ◽  
Effective Action ◽  
Black Hole Solution ◽  
Bosonic String ◽  
Superstring Theory ◽  
Integration Measure ◽  
String Loop ◽  
Bosonic String Theory ◽  
Closed Bosonic String

Following the ideas of Ref. 3, to account for instability of 2-D black hole solution, we discuss possible imaginary string-loop corrections to the coefficient at the Einstein term in string effective action (EA). In closed bosonic string theory, such corrections appear because of the tachyon contribution to the integration measure over the moduli. In superstring theory, several possible sources of complex one-string-loop contributions to the EA are considered. It is argued that none of them can account for complex corrections to the Einstein term in the effective action.

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 in magnetic monopoles with a dark halo

2019 ◽  
Vol 34 (01) ◽  
pp. 1950002 ◽  
Author(s):  
A. Lugo ◽  
J. M. Pérez Ipiña ◽  
F. A. Schaposnik
Keyword(s):  
Black Hole ◽  
Black Hole Solution ◽  
Scalar Potential ◽  
Magnetic Monopoles ◽  
Dark Halo ◽  
Higgs Potential ◽  
Coupling Constant ◽  
Horizon Radius ◽  
Yang Mills ◽  
Higgs Portal

We study a spontaneously broken Einstein–Yang–Mills–Higgs model coupled via a Higgs portal to an uncharged scalar [Formula: see text]. We present a phase diagram of self-gravitating solutions showing that depending on the choice of parameters of the [Formula: see text] scalar potential and the Higgs portal coupling constant [Formula: see text], one can identify different regions: If [Formula: see text] is sufficiently small, a [Formula: see text] halo is created around the monopole core which in turn surrounds a black hole. For larger values of [Formula: see text], no halo exists and the solution is just a black hole monopole one. When the horizon radius grows and becomes larger than the monopole radius, solely a black hole solution exists. Because of the presence of the [Formula: see text] scalar, a bound for the Higgs potential coupling constant exists and when it is not satisfied, the vacuum is unstable and no nontrivial solution exists. We briefly comment on possible connections of our results with those found in recent dark matter axion models.

scholarly journals ON BLACK HOLE CREATION IN PLANCKIAN ENERGY SCATTERING

1996 ◽  
Vol 05 (06) ◽  
pp. 707-721 ◽  
Author(s):  
I. YA. AREF’EVA ◽  
I.V. VOLOVICH ◽  
K.S. VISWANATHAN
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Waves ◽  
Black Hole Solution ◽  
Kerr Black Hole ◽  
Energy Scattering ◽  
Light Particles ◽  
Black Hole Creation ◽  
Plane Gravitational Waves

In a series of papers Amati, Ciafaloni and Veneziano and ’t Hooft conjectured that black holes occur in the collision of two light particles at planckian energies. In this talk based on [10] we discuss a possible scenario for such a process by using the Chandrasekhar-Ferrari-Xanthopoulos duality between the Kerr black hole solution and colliding plane gravitational waves.

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