404 research outputs found
Black Holes of a Minimal Size in String Gravity
A lower limit for a neutral black hole size is obtained in the frames of the
string gravity model with the second order curvature correction. It is shown
that this effect remains when the third order curvature correction is also
taken into account and argued that such restriction does exist in all
perturbative orders of curvature expansions.Comment: 6 LaTeX pages, 1 PostScript figure (epsfig.sty), minor changes in the
text and references, submitted to Int.J.Mod.Phy
Black Hole Relics in String Gravity: Last Stages of Hawking Evaporation
One of the most intriguing problem of modern physics is the question of the
endpoint of black hole evaporation. Based on Einstein-dilaton-Gauss-Bonnet four
dimensional string gravity model we show that black holes do not disappear and
that the end of the evaporation process leaves some relic. The possibility of
experimental detection of the remnant black holes is investigated. If they
really exist, such objects could be a considerable part of the non baryonic
dark matter in our Universe.Comment: 15 pages, accepted to Class. Quant. Gra
Kerr-Gauss-Bonnet Black Holes: An Analytical Approximation
Gauss-Bonnet gravity provides one of the most promising frameworks to study
curvature corrections to the Einstein action in supersymmetric string theories,
while avoiding ghosts and keeping second order field equations. Although
Schwarzschild-type solutions for Gauss-Bonnet black holes have been known for
long, the Kerr-Gauss-Bonnet metric is missing. In this paper, a five
dimensional Gauss-Bonnet approximation is analytically derived for spinning
black holes and the related thermodynamical properties are briefly outlined.Comment: 5 pages, 1 figur
Asymptotic properties of black hole solutions in dimensionally reduced Einstein-Gauss-Bonnet gravity
We study the asymptotic behavior of the spherically symmetric solutions of
the system obtained from the dimensional reduction of the six-dimensional
Einstein- Gauss-Bonnet action. We show that in general the scalar field that
parametrizes the size of the internal space is not trivial, but nevertheless
the solutions depend on a single parameter. In analogy with other models
containing Gauss-Bonnet terms, naked singularities are avoided if a minimal
radius for the horizon is assumed.Comment: 9 pages, plain Te
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