Black hole evaporation in conformal gravity

Abstract

We study the formation and the evaporation of a spherically symmetric black hole in conformal gravity. From the collapse of a spherically symmetric thin shell of radiation, we find a singularity-free non-rotating black hole. This black hole has the same Hawking temperature as a Schwarzschild black hole with the same mass, and it completely evaporates either in a finite or in an infinite time, depending on the ensemble. We consider the analysis both in the canonical and in the micro-canonical statistical ensembles. Last, we discuss the corresponding Penrose diagram of this physical process.

Formation and evaporation of an electrically charged black hole in conformal gravity

“…In the present paper, we continue our study on the formation and evaporation of black holes in conformal gravity extending our previous work [23][24][25][26]. In particular, we study the gravitational collapse of a spherically symmetric and electrically charged thin shell of radiation.…”

“…The outcome of the collapse is a spherically symmetric and electrically charged singularity-free black hole, which is the counterpart of the singular Reissner-Nordström solution in Einstein's gravity. We study the evaporation process and discuss our finding considering also the results of our previous work [26].…”

“…We now very briefly report the results of the analysis, whose main steps were laid down above and also in the previous paper [26]. The Hawking temperature reads here…”

“…In the uncharged case, studied in [26], the relation of proportionality L = α M was motivated by the fact that it solved the integral equations of evaporation. However, in the present charged case, we take a possible phenomenological assumption that the length scale L should depend on the characteristic length scales present in the original (non-rescaled) solution of the theory.…”

Quantum radiation from a sandwich black hole

“…Similar theory appears naturally also in the context of noncommutative geometry deformation of the Einstein gravity [11,12] (see a review [13] and references therein). The application of the ghost free theory of gravity to the problem of singularities in cosmology and black holes can be found in [14][15][16][17][18][19][20][21][22][23][24][25][26][27]. In spite of a number of promising results, we still do not have a final conclusive solution of this problem in the ghost-free gravity.…”