STATIC CHARGED DILATON BLACK HOLE SOLUTIONS IN NON-COMMUTATIVE SPACES

2007 ◽  
Vol 16 (01) ◽  
pp. 19-24
Author(s):  
M. R. SETARE ◽  
J. SADEGHI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Temperature ◽  
Dilaton Field ◽  
Commutative Case ◽  
Charged Black Holes ◽  
Extreme Black Hole ◽  
Dilaton Black Hole ◽  
Black Hole Solutions

Here we consider the black hole solutions which were obtained by Chan and Mann.1 These solutions represent static charged black holes with a dilaton field. Then we compute the corrections to the horizons and Hawking temperature of these black holes. These corrections stem from the space non-commutativity. We show that in a non-commutative case, temperature of extreme black hole, in contrast to that of the commutative case, is not zero.

scholarly journals CHARGED ROTATING BLACK HOLES IN DILATON GRAVITY

2007 ◽  
Vol 22 (26) ◽  
pp. 4849-4858 ◽  
Author(s):  
A. SHEYKHI ◽  
N. RIAZI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Dilaton Field ◽  
Dilaton Gravity ◽  
Charged Black Holes ◽  
Static Solutions ◽  
Rotating Black Holes ◽  
Small Rotation ◽  
Type Potential

We consider charged black holes with curved horizons, in five-dimensional dilaton gravity in the presence of Liouville-type potential for the dilaton field. We show how, by solving a pair of coupled differential equations, infinitesimally small angular momentum can be added to these static solutions to obtain charged rotating dilaton black hole solutions. In the absence of dilaton field, the nonrotating version of the solution reduces to the five-dimensional Reissner–Nordström black hole, and the rotating version reproduces the five-dimensional Kerr–Newman modification thereof for small rotation parameter. We also compute the angular momentum and the angular velocity of these rotating black holes which appear at the first order.

scholarly journals ENTROPY OF EXTREMAL DYONIC BLACK HOLES

1996 ◽  
Vol 11 (37) ◽  
pp. 2933-2939 ◽  
Author(s):  
A. GHOSH ◽  
P. MITRA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
String Theory ◽  
Extremal Black Hole ◽  
Classical Action ◽  
Charged Black Holes ◽  
Thermodynamic Entropy ◽  
Black Hole Solutions

For extremal charged black holes, the thermodynamic entropy is proportional to the mass or charges but not proportional to the area. This is demonstrated here for dyonic extremal black hole solutions of string theory. It is pointed out that these solutions have zero classical action although the area is nonzero. By combining the general form of the entropy allowed by thermodynamics with recent observations in the literature it is possible to fix the entropy almost completely.

scholarly journals Spherically symmetric black holes with electric and magnetic charge in extended gravity: physical properties, causal structure, and stability analysis in Einstein’s and Jordan’s frames

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
E. Elizalde ◽  
G. G. L. Nashed ◽  
S. Nojiri ◽  
S. D. Odintsov
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Stability Analysis ◽  
Physical Properties ◽  
Causal Structure ◽  
Hawking Temperature ◽  
The Novel ◽  
Extended Gravity ◽  
Static Black Hole ◽  
Black Hole Solutions

Abstract Novel static black hole solutions with electric and magnetic charges are derived for the class of modified gravities: $$f({{{\mathcal {R}}}})={{{\mathcal {R}}}}+2\beta \sqrt{{{\mathcal {R}}}}$$f(R)=R+2βR, with or without a cosmological constant. The new black holes behave asymptotically as flat or (A)dS space-times with a dynamical value of the Ricci scalar given by $$R=\frac{1}{r^2}$$R=1r2 and $$R=\frac{8r^2\Lambda +1}{r^2}$$R=8r2Λ+1r2, respectively. They are characterized by three parameters, namely their mass and electric and magnetic charges, and constitute black hole solutions different from those in Einstein’s general relativity. Their singularities are studied by obtaining the Kretschmann scalar and Ricci tensor, which shows a dependence on the parameter $$\beta $$β that is not permitted to be zero. A conformal transformation is used to display the black holes in Einstein’s frame and check if its physical behavior is changed w.r.t. the Jordan one. To this end, thermodynamical quantities, as the entropy, Hawking temperature, quasi-local energy, and the Gibbs free energy are calculated to investigate the thermal stability of the solutions. Also, the casual structure of the new black holes is studied, and a stability analysis is performed in both frames using the odd perturbations technique and the study of the geodesic deviation. It is concluded that, generically, there is coincidence of the physical properties of the novel black holes in both frames, although this turns not to be the case for the Hawking temperature.

scholarly journals S-DUALITY AND THE ENTROPY OF BLACK HOLES IN HETEROTIC STRING THEORY

1996 ◽  
Vol 11 (39n40) ◽  
pp. 3103-3111 ◽  
Author(s):  
AMIT GHOSH ◽  
JNANADEVA MAHARANA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Partition Function ◽  
Heterotic String ◽  
Heterotic String Theory ◽  
Charged Black Holes ◽  
Duality Transformations ◽  
Extremal Limit ◽  
Electrically Charged ◽  
Black Hole Solutions

Four-dimensional heterotic string effective action is known to admit non-rotating electrically and magnetically charged black hole solutions. The partition function and entropy is computed for electrically charged black holes and is vanishing in some extremal limit. For the magnetically charged black holes the entropy is also argued to be vanishing in the same extremal limit when these black hole solutions are related by S-duality transformations.

scholarly journals Dirac quasinormal modes of power-Maxwell charged black holes in Rastall gravity

2020 ◽  
Vol 35 (23) ◽  
pp. 2050193
Author(s):  
Cai-Ying Shao ◽  
Yu Hu ◽  
Yu-Jie Tan ◽  
Cheng-Gang Shao ◽  
Kai Lin ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Matrix Method ◽  
Quasinormal Modes ◽  
Einstein Gravity ◽  
Late Time ◽  
Charged Black Holes ◽  
The Matrix ◽  
Black Hole Solutions ◽  
Extremal Black Holes

In this paper, we study the quasinormal modes of the massless Dirac field for charged black holes in Rastall gravity. The spherically symmetric black hole solutions in question are characterized by the presence of a power-Maxwell field, surrounded by the quintessence fluid. The calculations are carried out by employing the WKB approximations up to the 13th-order, as well as the matrix method. The temporal evolution of the quasinormal modes is investigated by using the finite difference method. Through numerical simulations, the properties of the quasinormal frequencies are analyzed, including those for the extremal black holes. Among others, we explore the case of a second type of extremal black holes regarding the Nariai solution, where the cosmical and event horizon coincide. The results obtained by the WKB approaches are found to be mostly consistent with those by the matrix method. It is observed that the magnitudes of both real and imaginary parts of the quasinormal frequencies increase with increasing [Formula: see text], the spin–orbit quantum number. Also, the roles of the parameters [Formula: see text] and [Formula: see text], associated with the electric charge and the equation of state of the quintessence field, respectively, are investigated regarding their effects on the quasinormal frequencies. The magnitude of the electric charge is found to sensitively affect the time scale of the first stage of quasinormal oscillations, after which the temporal oscillations become stabilized. It is demonstrated that the black hole solutions for Rastall gravity in asymptotically flat spacetimes are equivalent to those in Einstein gravity, featured by different asymptotical spacetime properties. As one of its possible consequences, we also investigate the behavior of the late-time tails of quasinormal models in the present model. It is found that the asymptotical behavior of the late-time tails of quasinormal modes in Rastall theory is governed by the asymptotical properties of the spacetimes of their counterparts in Einstein gravity.

Charged black holes in the infinite derivative theory of gravity

2021 ◽  
Author(s):  
Yong Xiao ◽  
Longting Zhang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Electromagnetic Field ◽  
Electrostatic Potential ◽  
Einstein Gravity ◽  
First Law Of Thermodynamics ◽  
Charged Black Holes ◽  
Theory Of Gravity ◽  
Infinite Derivative ◽  
Black Hole Solutions

Abstract The infinite derivative theory of gravity is a generalization of Einstein gravity with many interesting properties, but the black hole solutions in this theory are still not fully understood. In the paper, we concentrate on studying the charged black holes in such a theory. Adding the electromagnetic field part to the effective action, we show how the black hole solutions around the Reissner-Nordstr{\"o}m metric can be solved perturbatively and iteratively. We further calculate the corresponding temperature, entropy and electrostatic potential of the black holes and verify the first law of thermodynamics.

scholarly journals MULTI-BLACK HOLES AND INSTANTONS IN EFFECTIVE STRING THEORY

1998 ◽  
Vol 07 (01) ◽  
pp. 73-80
Author(s):  
S. DEMELIO ◽  
S. MIGNEMI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
String Theory ◽  
Higher Dimensions ◽  
Field Equations ◽  
Charged Black Holes ◽  
Effective String Theory ◽  
Black Hole Solutions

The effective four-dimensional action for string theory contains non-minimal couplings of the dilaton and the moduli arising from the compactification of higher dimensions. We show that the resulting field equations admit multi-black hole solutions. The Euclidean continuation of these solutions can be interpreted as an instanton mediating the splitting and recombination of the throat of extremal magnetically charged black holes.

scholarly journals A Smarr formula for charged black holes in nonlinear electrodynamics

2017 ◽  
Vol 32 (39) ◽  
pp. 1750219 ◽  
Author(s):  
Leonardo Balart ◽  
Sharmanthie Fernando
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
General Formula ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Nonlinear Electrodynamics ◽  
Spherically Symmetric ◽  
Charged Black Holes ◽  
Electrically Charged ◽  
Black Hole Solutions

It is well known that the Smarr formula does not hold for black holes in nonlinear electrodynamics. The main reason for this is the fact that the trace of the energy–momentum tensor for nonlinear electrodynamics does not vanish as it is for Maxwell’s electrodynamics. Starting from the Komar integral, we derived a new Smarr-type formula for spherically symmetric static electrically charged black hole solutions in nonlinear electrodynamics. We show that this general formula is in agreement with some that are obtained for black hole solutions with nonlinear electrodynamics.

Thermodynamics of charged Newman–Unti–Tamburino accelerating rotating black holes

2013 ◽  
Vol 91 (3) ◽  
pp. 236-241 ◽  
Author(s):  
M. Sharif ◽  
Wajiha Javed
Keyword(s):  
Black Holes ◽  
Heat Capacity ◽  
Black Hole ◽  
Hawking Temperature ◽  
Surface Gravity ◽  
Thermodynamic Quantities ◽  
Field Equations ◽  
First Law Of Thermodynamics ◽  
Rotating Black Holes ◽  
Black Hole Solutions

This paper is devoted to studying the thermodynamics of charged Newman–Unti–Tamburino black hole solutions to the field equations, including rotation and acceleration. We evaluate some thermodynamic quantities like surface gravity, Hawking temperature, the entropy–area relationship, heat capacity, and the first law of thermodynamics. These quantities reduce to the results already available in the literature for some particular cases. We also explore their graphical behavior.

scholarly journals Extremal black holes that are not extremal: maximal warm holes

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Óscar J. C. Dias ◽  
Gary T. Horowitz ◽  
Jorge E. Santos
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Temperature ◽  
Charged Scalar ◽  
Asymptotically Flat ◽  
Charged Black Holes ◽  
Maximum Charge ◽  
Scalar Hair ◽  
Hairy Black Hole ◽  
Extremal Black Holes

Abstract We study a family of four-dimensional, asymptotically flat, charged black holes that develop (charged) scalar hair as one increases their charge at fixed mass. Surprisingly, the maximum charge for given mass is a nonsingular hairy black hole with nonzero Hawking temperature. The implications for Hawking evaporation are discussed.

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