Entropy Spectrum of a Carged Black Hole of Heterotic String Theory via Adiabatic Invariance

Using adiabatic invariance and the Bohr-Sommerfeld quantization rule we investigate the entropy spectroscopy of a charged black hole of heterotic string theory. It is shown that the entropy spectrum is equally spaced identically to the Schwarzschild, Reissner-Nordstr\"om and Kerr black holes. Since the adiabatic invariance method does not use quasinormal mode analysis, there is no need to impose the small charge limit and no confusion on whether the real part or imaginary part is responsible for the entropy spectrum.Comment: 8 pages, no figure

On the Thermodynamical Relation between Rotating Charged BTZ Black Holes and Effective String Theory

In this paper we study the first law of thermodynamics for the (2+1) dimensional rotating charged BTZ black hole considering a pair of thermodinamical systems constructed with the two horizons of this solution. We show that these two systems are similar to the right and left movers of string theory and that the temperature associated with the black hole is the harmonic mean of the temperatures associated with these two systems.Comment: 9 page

A Rotating Charged Black Hole Solution in f(R) Gravity

In the context of f(R) theories of gravity, we address the problem of finding a rotating charged black hole solution in the case of constant curvature. The new metric is obtained by solving the field equations and we show that the behavior of it is typical of a rotating charged source. In addition, we analyze the thermodynamics of the new black hole. The results ensures that the thermodynamical properties in f(R) gravities are qualitatively similar to those of standard General Relativity.Comment: 9 pages, no figure

Entropy of the Kerr-Sen Black Hole

We study the entropy of Kerr-Sen black hole of heterotic string theory beyond semiclassical approximations. Applying the properties of exact differentials for three variables to the first law thermodynamics we derive the corrections to the entropy of the black hole. The leading (logarithmic) and non leading corrections to the area law are obtained.Comment: 8 pages. Corrected references

Noncommutative Geometry Inspired Rotating Black Hole in Three Dimensions

We find a new rotating black hole in three-dimensional anti-de Sitter space using an anisotropic perfect fluid inspired by the noncommutative black hole. We deduce the thermodynamical quantities of this black hole and compare them with those of a rotating BTZ solution.Comment: 7 page

Geometric Description of the Thermodynamics of the Noncommutative Schwarzschild Black Hole

The thermodynamics of the noncommutative Schwarzschild black hole is reformulated within the context of the recently developed formalism of geometrothermodynamics (GTD). Using a thermodynamic metric which is invariant with respect to Legendre transformations, we determine the geometry of the space of equilibrium states and show that phase transitions, which correspond to divergencies of the heat capacity, are represented geometrically as singularities of the curvature scalar. This further indicates that the curvature of the thermodynamic metric is a measure of thermodynamic interaction

A Topologically Charged Rotating Black Hole in the Brane

We have obtained a rotating black hole solution in the braneworld scenario by applying the Newman-Janis algorithm. The new solution carries two types of charge, one arising from the bulk Weyl tensor and one from the gauge field trapped on the brane. In order to obtain this result, we used a modified version of the algorithm in which the involved complexification is the key point. The analysis of the horizon structure of the new metric shows similarities to the Kerr-Newman solution. In particular, there is a minimal mass to which the black hole can decay through the Hawking radiation. From the thermodynamical analysis, the possibility of a degenerate horizon gives a temperature that, instead of a divergent behaviour at short scales, admits both a minimum and a maximum before cooling down towards a zero temperature remnant configuration

Electrostatics in the Surroundings of a Topologically Charged Black Hole

We determine the expression for the electrostatic potential generated by a point charge held stationary in the topologically charged black hole spacetime arising from the Randall-Sundrum II braneworld model. We treat the static electric point charge as a linear perturbation on the black hole background and an expression for the electrostatic multipole solution is given: PACS: 04.70.-s, 04.50. Gh, 41.90.+e