scholarly journals Analytic solutions of the geodesic equation for Einstein-Maxwell-dilaton-axion black holes

2015 ◽  
Vol 92 (10) ◽  
Author(s):  
Kai Flathmann ◽  
Saskia Grunau
Keyword(s):  
Black Holes ◽  
Analytic Solutions ◽  
Geodesic Equation

scholarly journals EVOLUTION OF PRIMORDIAL BLACK HOLE MASS SPECTRUM IN BRANS–DICKE THEORY

2013 ◽  
Vol 22 (05) ◽  
pp. 1350022 ◽  
Author(s):  
D. DWIVEDEE ◽  
B. NAYAK ◽  
L. P. SINGH
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Mass Spectrum ◽  
Energy Density ◽  
Analytic Solutions ◽  
Primordial Black Hole ◽  
Primordial Black Holes ◽  
Black Hole Mass ◽  
Linear And Nonlinear ◽  
The Universe

We investigate the evolution of primordial black hole mass spectrum by including both accretion of radiation and Hawking evaporation within Brans–Dicke (BD) cosmology in radiation-, matter- and vacuum-dominated eras. We also consider the effect of evaporation of primordial black holes on the expansion dynamics of the universe. The analytic solutions describing the energy density of the black holes in equilibrium with radiation are presented. We demonstrate that these solutions act as attractors for the system ensuring stability for both linear and nonlinear situations. We show, however, that inclusion of accretion of radiation delays the onset of this equilibrium in all radiation-, matter- and vacuum-dominated eras.

scholarly journals Electromagnetic quasitopological gravities

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Pablo A. Cano ◽  
Ángel Murcia
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Equations Of Motion ◽  
Analytic Solutions ◽  
Maxwell Theory ◽  
Fully Integrated ◽  
Higher Derivative ◽  
Metric Function ◽  
Minimal Mass ◽  
Extremal Black Holes

Abstract We identify a set of higher-derivative extensions of Einstein-Maxwell theory that allow for spherically symmetric charged solutions characterized by a single metric function f (r) = −gtt = 1/grr. These theories are a non-minimally coupled version of the recently constructed Generalized Quasitopological gravities and they satisfy a number of properties that we establish. We study magnetically-charged black hole solutions in these new theories and we find that for some of them the equations of motion can be fully integrated, enabling us to obtain analytic solutions. In those cases we show that, quite generally, the singularity at the core of the black hole is removed by the higher-derivative corrections and that the solution describes a globally regular geometry. In other cases, the equations are reduced to a second order equation for f (r). Nevertheless, for all the theories it is possible to study the thermodynamic properties of charged black holes analytically. We show that the first law of thermodynamics holds exactly and that the Euclidean and Noether-charge methods provide equivalent results. We then study extremal black holes, focusing on the corrections to the extremal charge-to-mass ratio at a non-perturbative level. We observe that in some theories there are no extremal black holes below certain mass. We also show the existence of theories for which extremal black holes do not represent the minimal mass state for a given charge. The implications of these findings for the evaporation process of black holes are discussed.

scholarly journals Topological or rotational non-Abelian gauge fields from Einstein-Skyrme holography

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Casey Cartwright ◽  
Benjamin Harms ◽  
Matthias Kaminski
Keyword(s):  
Field Theory ◽  
Black Holes ◽  
Analytic Solutions ◽  
Charge Density Waves ◽  
Entropy Density ◽  
Hawking Temperature ◽  
De Sitter ◽  
Abelian Gauge ◽  
Qcd Phase Diagram ◽  
Chern Numbers

Abstract We report analytically known states at non-zero temperature which may serve as a powerful tool to reveal common topological and thermodynamic properties of systems ranging from the QCD phase diagram to topological phase transitions in condensed matter materials. In the holographically dual gravity theory, these are analytic solutions to a five-dimensional non-linear-sigma (Skyrme) model dynamically coupled to Einstein gravity. This theory is shown to be holographically dual to $$ \mathcal{N} $$ N = 4 Super-Yang-Mills theory coupled to an SU(2)-current. All solutions are fully backreacted asymptotically Anti-de Sitter (AdS) black branes or holes. One family of global AdS black hole solutions contains non-Abelian gauge field configurations with positive integer Chern numbers and finite energy density. Larger Chern numbers increase the Hawking-Page transition temperature. In the holographically dual field theory this indicates a significant effect on the deconfinement phase transition. Black holes with one Hawking temperature can have distinct Chern numbers, potentially enabling topological transitions. A second family of analytic solutions, rotating black branes, is also provided. These rotating solutions induce states with propagating charge density waves in the dual field theory. We compute the Hawking temperature, entropy density, angular velocity and free energy for these black holes/branes. These correspond to thermodynamic data in the dual field theory. For these states the energy-momentum tensor, (non-)conserved current, and topological charge are interpreted.

Stationary configurations around charged rotating black holes

2016 ◽  
Vol 25 (09) ◽  
pp. 1641012
Author(s):  
Carolina L. Benone
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Bound States ◽  
Scalar Fields ◽  
Analytic Solutions ◽  
Massive Scalar ◽  
Massive Scalar Field ◽  
Rotating Black Holes ◽  
Specific Frequency

Scalar fields can form real bound states around black holes for a specific frequency. In this work, we review the case of a charged and massive scalar field around a charged rotating black hole, in order to find these bound states. We analyze the behavior of these solutions for different parameters and also comment on analytic solutions for certain regimes.

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