Non-inheriting Einstein-Maxwell theory and black holes

2008 ◽  
Vol 30 ◽  
pp. 107-109
Author(s):  
P. Tod
Keyword(s):  
Author(s):  
Xian-Hui Ge ◽  
Sang-Jin Sin

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.


2015 ◽  
Vol 2015 (10) ◽  
Author(s):  
Alfredo Pérez ◽  
Miguel Riquelme ◽  
David Tempo ◽  
Ricardo Troncoso

2016 ◽  
Vol 25 (01) ◽  
pp. 1650010 ◽  
Author(s):  
S. H. Hendi ◽  
S. Panahiyan ◽  
B. Eslam Panah

In this paper, we take into account the black-hole solutions of Einstein gravity in the presence of logarithmic and exponential forms of nonlinear electrodynamics. At first, we consider the cosmological constant as a dynamical pressure to study the phase transitions and analogy of the black holes with the Van der Waals liquid–gas system in the extended phase space. We make a comparison between linear and nonlinear electrodynamics and show that the lowest critical temperature belongs to Maxwell theory. Also, we make some arguments regarding how power of nonlinearity brings the system to Schwarzschild-like and Reissner–Nordström-like limitations. Next, we study the critical behavior of the system in the context of heat capacity. We show that critical behavior of system is similar to the one in phase diagrams of extended phase space. We also extend the study of phase transition points through geometrical thermodynamics (GTs). We introduce two new thermodynamical metrics for extended phase space and show that divergencies of thermodynamical Ricci scalar (TRS) of the new metrics coincide with phase transition points of the system. Then, we introduce a new method for obtaining critical pressure and horizon radius by considering denominator of the heat capacity.


2016 ◽  
Vol 25 (06) ◽  
pp. 1650063 ◽  
Author(s):  
S. H. Hendi ◽  
S. Panahiyan ◽  
M. Momennia

In this paper, we consider quadratic Maxwell invariant as a correction to the Maxwell theory and study thermodynamic behavior of the black holes in Einstein and Gauss–Bonnet gravities. We consider cosmological constant as a thermodynamic pressure to extend phase space. Next, we obtain critical values in case of variation of nonlinearity and Gauss–Bonnet parameters. Although the general thermodynamical behavior of the black hole solutions is the same as usual Van der Waals system, we show that in special case of the nonlinear electromagnetic field, there will be a turning point for the phase diagrams and usual Van der Waals is not observed. This theory of nonlinear electromagnetic field provides two critical horizon radii. We show that this unusual behavior of phase diagrams is due to existence of second critical horizon radius. It will be pointed out that the power of the gravity and nonlinearity of the matter field modify the critical values. We generalize the study by considering the effects of dimensionality on critical values and make comparisons between our models with their special sub-classes. In addition, we examine the possibility of the existence of the reentrant phase transitions through two different methods.


Axioms ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 33 ◽  
Author(s):  
Grigoris Panotopoulos

We compute the quasinormal frequencies for scalar perturbations of charged black holes in five-dimensional Einstein-power-Maxwell theory. The impact on the spectrum of the electric charge of the black holes, of the angular degree, of the overtone number, and of the mass of the test scalar field is investigated in detail. The quasinormal spectra in the eikonal limit are computed as well for several different space-time dimensionalities.


2006 ◽  
Vol 2 (S238) ◽  
pp. 139-144
Author(s):  
Jiří Bičák ◽  
Vladimír Karas ◽  
Tomáš Ledvinka

AbstractStationary axisymmetric magnetic fields are expelled from outer horizons of black holes as they become extremal. Extreme black holes exhibit Meissner effect also within exact Einstein–Maxwell theory and in string theories in higher dimensions. Since maximally rotating black holes are expected to be astrophysically most important, the expulsion of the magnetic flux from their horizons represents a potential threat to an electromagnetic mechanism launching the jets at the account of black-hole rotation.


2005 ◽  
Vol 20 (28) ◽  
pp. 6461-6485 ◽  
Author(s):  
HONGSU KIM ◽  
HYUNG MOK LEE

It was originally thought that Bonnor's solution in Einstein–Maxwell theory describes a singular point-like magnetic dipole. Lately, however, it has been demonstrated that indeed it may describe a black dihole, i.e. a pair of static, oppositely-charged extremal black holes with regular horizons. Motivated particularly by this new interpretation, in the present work, the construction and extensive analysis of a solution in the context of the Brans–Dicke–Maxwell theory representing a black dihole are attempted. It has been known for some time that the solution-generating algorithm of Singh and Rai produces stationary, axisymmetric, charged solutions in Brans–Dicke–Maxwell theory from the known such solutions in Einstein–Maxwell theory. Thus this algorithm of Singh and Rai's is employed in order to construct a Bonnor-type magnetic black dihole solution in Brans–Dicke–Maxwell theory from the known Bonnor solution in Einstein–Maxwell theory. The peculiar features of the new solution including internal infinity nature of the symmetry axis and its stability issue have been discussed in full detail.


2006 ◽  
Vol 23 (23) ◽  
pp. 6919-6925 ◽  
Author(s):  
Hideki Ishihara ◽  
Masashi Kimura ◽  
Ken Matsuno ◽  
Shinya Tomizawa

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