scholarly journals Thermodynamically stable asymptotically flat hairy black holes with a dilaton potential: the general case

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Dumitru Astefanesei ◽  
Jose Luis Blázquez-Salcedo ◽  
Francisco Gómez ◽  
Raúl Rojas
Keyword(s):  
Black Holes ◽  
Thermodynamic Stability ◽  
General Class ◽  
Spherically Symmetric ◽  
Spatial Infinity ◽  
Asymptotically Flat ◽  
Equilibrium Configurations ◽  
Hairy Black Holes ◽  
Extremal Limit ◽  
Stable Solutions

Abstract We extend the analysis, initiated in [1], of the thermodynamic stability of four-dimensional asymptotically flat hairy black holes by considering a general class of exact solutions in Einstein-Maxwell-dilaton theory with a non-trivial dilaton potential. We find that, regardless of the values of the parameters of the theory, there always exists a sub-class of hairy black holes that are thermodynamically stable and have the extremal limit well defined. This generic feature that makes the equilibrium configurations locally stable should be related to the properties of the dilaton potential that is decaying towards the spatial infinity, but behaves as a box close to the horizon. We prove that these thermodynamically stable solutions are also dynamically stable under spherically symmetric perturbations.

ENERGY LOCALIZATION FOR DILATONIC BLACK HOLE GEOMETRIES WITH A PURE MONOPOLE FIELD

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1253-1258
Author(s):  
I. RADINSCHI ◽  
T. GRAMMENOS
Keyword(s):  
Black Holes ◽  
Dimensional Space ◽  
Spherically Symmetric ◽  
Dilaton Field ◽  
Energy Localization ◽  
Asymptotically Flat ◽  
Adm Mass ◽  
Hairy Black Holes ◽  
Momentum Complex ◽  
Dilatonic Black Hole

The energy distribution of black holes with a dilaton and a pure monopole field is calculated by using Møller's energy–momentum complex. The four-dimensional space–times considered are static, spherically symmetric and asymptotically flat, exact solutions stemming from an action that besides gravity contains a dilaton field and a pure monopole field. The resulting "hairy" black holes have an essential singularity at the origin and two horizons. The energy obtained depends on the value of the dilaton field, the monopole charge and the ADM mass. All the momenta vanish for the space–time geometries considered.

scholarly journals Thermodynamically stable asymptotically flat hairy black holes with a dilaton potential

2019 ◽  
Vol 2019 (3) ◽  
Author(s):  
Dumitru Astefanesei ◽  
David Choque ◽  
Francisco Gómez ◽  
Raúl Rojas
Keyword(s):  
Black Holes ◽  
Asymptotically Flat ◽  
Hairy Black Holes

scholarly journals On the temperature dependence of the absorption cross-section for black holes in string theory

2015 ◽  
Vol 24 (09) ◽  
pp. 1542011 ◽  
Author(s):  
Filipe Moura
Keyword(s):  
Black Holes ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Low Frequency ◽  
Spherically Symmetric ◽  
Absorption Cross ◽  
Explicit Dependence ◽  
Superstring Theory ◽  
Classical Level ◽  
Extremal Limit

We study the low frequency absorption cross-section of spherically symmetric nonextremal d-dimensional black holes. In the presence of α′ corrections, this quantity must have an explicit dependence on the Hawking temperature of the form 1/TH. This property of the low frequency absorption cross-section is shared by the D1-D5 system from type IIB superstring theory already at the classical level, without α′ corrections. We apply our formula to the simplest example, the classical d-dimensional Reissner–Nordström solution, checking that the obtained formula for the cross-section has a smooth extremal limit. We also apply it for a d-dimensional Tangherlini-like solution with α′3 corrections.

scholarly journals Newtonian wormholes with spherical symmetry and tidal forces on test particles

2015 ◽  
Vol 24 (09) ◽  
pp. 1542020 ◽  
Author(s):  
Paulo Luz ◽  
José P. S. Lemos
Keyword(s):  
Black Holes ◽  
Mass Density ◽  
Particle Dynamics ◽  
Spherically Symmetric ◽  
Tidal Effects ◽  
Curved Space ◽  
Asymptotically Flat ◽  
Newtonian Gravitation ◽  
Tidal Forces ◽  
Test Particles

A spherically symmetric wormhole in Newtonian gravitation in curved space, enhanced with a connection between the mass density and the Ricci scalar, is presented. The wormhole, consisting of two connected asymptotically flat regions, inhabits a spherically symmetric curved space. The gravitational potential, gravitational field and the pressure that supports the fluid that permeates the Newtonian wormhole are computed. Particle dynamics and tidal effects in this geometry are studied. The possibility of having Newtonian black holes in this theory is sketched.

scholarly journals Extremal charged Vaidya and its near horizon geometry

2017 ◽  
Vol 26 (04) ◽  
pp. 1750036
Author(s):  
S. Sadeghian ◽  
A. Shafiekhani
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Black Hole Solution ◽  
Spherically Symmetric ◽  
Nonstationary Solution ◽  
Vaidya Black Hole ◽  
Extremal Limit ◽  
Horizon Geometry ◽  
Extremal Black Holes

Recently [Formula: see text]-dimensional spherically symmetric charged Vaidya black hole solution has been constructed. We observe that this nonstationary solution admits extremal limit and study its near horizon geometry. We show that the symmetry of the near horizon geometry is [Formula: see text]. Our analysis shows that the theorems for the near horizon geometry of stationary extremal black holes, may be extended to nonstationary cases.

scholarly journals BULK SHAPE OF BRANE-WORLD BLACK HOLES

2003 ◽  
Vol 18 (09) ◽  
pp. 651-660 ◽  
Author(s):  
ROBERTO CASADIO ◽  
LORENZO MAZZACURATI
Keyword(s):  
Black Holes ◽  
Brane World ◽  
Spherically Symmetric ◽  
Exact Integration ◽  
Asymptotically Flat

We propose a method to extend to the bulk asymptotically flat static spherically symmetric brane-world metrics. We employ the multipole (1/r) expansion in order to allow the exact integration of the relevant equations along the (fifth) extra coordinate and make contact with the parametrized post-Newtonian formalism. We apply our method to three families of solutions previously appeared as candidates of black holes in the brane world and show that the shape of the horizon is very likely a flat "pancake" for astrophysical sources.

scholarly journals Particle Motion around Charged Black Holes in Generalized Dilaton-Axion Gravity

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Susmita Sarkar ◽  
Farook Rahaman ◽  
Irina Radinschi ◽  
Theophanes Grammenos ◽  
Joydeep Chakraborty
Keyword(s):  
Black Holes ◽  
Gravitational Field ◽  
Effective Potential ◽  
Particle Motion ◽  
Spherically Symmetric ◽  
Asymptotically Flat ◽  
Four Dimensions ◽  
Charged Black Holes ◽  
Test Particles ◽  
Massive Particles

The behaviour of massive and massless test particles around asymptotically flat and spherically symmetric, charged black holes in the context of generalized dilaton-axion gravity in four dimensions is studied. All the possible motions are investigated by calculating and plotting the corresponding effective potential for the massless and massive particles as well. Further, the motion of massive (charged or uncharged) test particles in the gravitational field of charged black holes in generalized dilaton-axion gravity for the cases of static and nonstatic equilibrium is investigated by applying the Hamilton-Jacobi approach.

Non-existence of equilibrium configurations of charged black holes

1980 ◽  
Vol 372 (1751) ◽  
pp. 535-538 ◽  
Keyword(s):  
Black Holes ◽  
Mass Ratio ◽  
Existence Of Equilibrium ◽  
Asymptotically Flat ◽  
Charged Black Holes ◽  
Equilibrium Configurations ◽  
Degenerate Solutions

I show that the only axisymmetric, static, asymptotically flat multi-blackhole configurations, each with the same charge to mass ratio, are the degenerate solutions of Hartle & Hawking (1972).

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