AbstractsAstronomy & Space Science

Study of black hole solution properties in the context of 4- and higher-dimensional gravity theories

by Nikolaos Pappas




Institution: University of Ioannina; Πανεπιστήμιο Ιωαννίνων
Department:
Year: 2013
Keywords: Μελανές οπές; Μοντέλα βρανών; Ακτινοβολία Hawking; Γενική σχετικότητα; Μετρική Myers-Perry; Τανυστικά βαρυτόνια; Έμμαζα βαθμωτά πεδία; Παράδοξο της πληροφορίας; Brane world models; Brane world models; Hawking radiation; General relativity; Myers-Perry metric; Tensor-type gravitons; Massive scalar fields; Information loss paradox
Record ID: 1154293
Full text PDF: http://hdl.handle.net/10442/hedi/29082


Abstract

The present dissertation is dedicated to the study of the black hole properties. To be more exact, we mainly focused our work on the study of the energy spectrum emitted by higher-dimensional black holes with respect to their angular momentum and the number of the extra dimensions. The motivation is the possibility of creating higher dimensional miniature black holes in ground-based experiments (like LHC) where their evaporation would take place in front of our detectors and consequently get recorded with great detail. The reason for this possibility is that in the context of the so-called brane world models, the fundamental energy scale for gravity could be as low as a few TeV, an energy region which lies well inside the abilities of current to explore. If we manage to produce a black hole and observe its Hawking emission, we could infer with certainty the existence of extra spatial dimensions of spacetime. In order to do so, though, we have to have a clear idea about the properties of the spectrum. A large part of the dissertation is about our work concerning exactly these properties. In specific, we studied the emission of tensor-type gravitons and massive scalars from a higher-dimensional black hole. We showed that the energy emitted through these degrees of freedom increases with the increase of the number of extra dimensions considered and/or the increase of the black hole angular momentum, while in the case of massive scalar the energy emission decreases with the increase of the particle mass. We also studied the angular distribution of the emitted energy in the case of fermions and bosons in an attempt to find a way to determine the black hole angular momentum regardless of the value of the n parameter, which denotes the number of extra dimensions. Then, we moved on to study a still open question about the possibility to construct a stable black hole solution localized on the brane in the context of the Randall- Sundrum II model and which energy distribution is necessary for such a solution to exist. We showed that a single conformally-coupled with gravity scalar cannot under any assumption lead to a viable solution. Furthermore, for minimally-coupled with gravity scalars we showed that no field theory model containing one or two scalars, no matter how general, can support an acceptable black hole solution. Finally, we turned our attention to the celebrated information loss paradox for black holes and we proposed a couple of novel ideas that could resolve it. The first one is based on the assumption that there are two kinds of information in Nature (fundamental and secondary) and in this context information is both preserved and destroyed by black holes. Also, that it is necessary to recognize the contribution of the EPR phenomenon in the overall formation/evaporation process of the black holes in order for the latter to become consistent with our quantum-mechanical picture of the world. Η παρούσα διατριβή επικεντρώνεται στη μελέτη των μελανών οπών. Είναι γνωστό ότι οι μελανές οπές εκπέμπουν σωματίδια, με…