Black holes and scalar fields

Entropies of Scalar Fields on Three Dimensional Black Holes

Thermodynamics of scalar fields is investigated in three dimensional black hole backgrounds in two approaches. One is mode expansion and direct computation of the partition sum, and the other is the Euclidean path integral approach. We obtain a number of exact results, for example, mode functions, Hartle-Hawking Green functions on the black holes, Green functions on a cone geometry, free energi...

Scalar Black Holes

A class of exact regular spherically symmetric solutions to the Einstein equation obeying Dymnikova’s definition T 1 1 = T 0 0 of vacuumlike state is considered. These solutions, that may be interpreted as black holes, are not only singularity free, but also do not set us thinking about the loss of information under gravitational collapse. However, according to the singularity theorems, the geo...

Magnetic Fields Around Black Holes

Title of Dissertation: Magnetic Fields Around Black Holes David A. G. Garofalo, Doctor of Philosophy, 2008 Dissertation directed by: Professor Christopher Stephen Reynolds Department of Astronomy Active Galactic Nuclei are the most powerful long-lived objects in the universe. They are thought to harbor supermassive black holes that range from 1 million solar masses to 1000 times that value and ...

Cold Black Holes in Scalar-tensor Theories

We study the possible existence of black holes in scalar-tensor theories of gravity in four dimensions. Their existence is verified for anomalous versions of these theories, with a negative kinetic term in the Lagrangian. The Hawking temperature TH of these holes is zero, while the horizon area is (in most cases) infinite. It is shown that an infinite value of TH can occur only at a curvature s...

Charged black holes with scalar hair.