Black holes in f(T,B) gravity: exact and perturbed solutions

Sectors of solutions in Three-dimensional Gravity and Black Holes

We examine the connection between three dimensional gravity with negative cosmological constant and two-dimensional CFT via the Chern-Simons formulation. A set of generalized spectral flow transformations are shown to yield new sectors of solutions. One implication is that the microscopic calculation of the entropy of the Bañados-Teitelboim-Zanelli (BTZ) black hole is corrected by a multiplicat...

Exact solutions of four-dimensional black holes in string theory.

We construct an exact conformal field theory as an SL(2, R) × SU(2)/U(1)2 gauged WZW model, which describes a black hole in four dimensions. Another exact solution, describing a black membrane in four dimensions (in the sense that the event horizon is an infinite plane) is found as an SL(2, R)×U(1)2/U(1) gauged WZW model. Both the black hole and the black membrane carry axionic charge. Finally,...

Vortices and black holes in dilatonic gravity

The extrapolation of the black hole ‘no-hair’ conjecture, initially proposed by Ruffini and Wheeler [1] and stating that a stationary black hole is uniquely determined by its mass, electromagnetic charge and angular momentum, to the stronger statement of ‘no dressing’ of the horizon, has been proven to be false [2], [3]. A common feature of such ‘counterexamples’ is that they involve nontrivial...

Varying Constants, Black Holes, and Quantum Gravity

Tentative observations and theoretical considerations have recently led to renewed interest in models of fundamental physics in which certain “constants” vary in time. Davies, Davis and Lineweaver [1] have argued that the laws of black hole thermodynamics disfavor models in which the fundamental electric charge e changes. I show that similar considerations severely constrain “varying speed of l...

Black holes in three-dimensional topological gravity.