Μαύρες οπές με αξιονικά νέφη σε τροποποιημένη βαρύτητα Chern-Simons -

Βλάχος, Σωτήρης; Vlachos, Sotiris

dc.contributor.author	Βλάχος, Σωτήρης	el
dc.contributor.author	Vlachos, Sotiris	en
dc.date.accessioned	2023-03-28T11:10:32Z
dc.date.available	2023-03-28T11:10:32Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/57348
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.25046
dc.rights	Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/gr/	*
dc.subject	Ηair black holes	en
dc.subject	Axion gravity	en
dc.title	Μαύρες οπές με αξιονικά νέφη σε τροποποιημένη βαρύτητα Chern-Simons -	el
dc.title	Black Holes with Axionic Clouds in Chern-Simons Modified Gravity	en
heal.type	masterThesis
heal.classification	physics	el
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2023-02-23
heal.abstract	The first formulation of the no-hair conjecture, first posed by Werner Israel and reformulated by Bekenstein, states that black holes can be completely described only by three parameters, the angular momentum, the mass and the electric charge, quantities that can be measured asymptotically and are subject to a Gauss law. No other physical quantities, to which “hair” gives some kind of a metaphor, should exist. Black holes are uniquely determined by these three parameters, and other information about the matter that formed the black hole ”disappears” behind the black hole’s event horizon, being permanently inaccessible to external observers. An intuitive perspective is given when we consider, in this context, the impact of the energy conditions. These energy conditions imply ”reasonable impacts” on the underlined geometry from the presence of matter and energy, in agreement with the gravitational equations of motion. There is a close relation between the violation of the energy conditions and the hair of a black hole. Hairy black holes solutions have been found in multiple cases. The introduction of a negative cosmological constant or the coupling of a (pseudo-)scalar field with higher order curvature terms are just some examples of cases where hair does exist. In all of these cases, the energy conditions are violated, which gives us the physical intuition that the evasion of the no-hair theorems is achived by the violation of these conditions. Modified theories of gravity provide a great area to seek for ”hairy” solutions. In this thesis, we examine the Chern Simons modified gravity, defined as the sum of the Einstein-Hilbert action and a new, higher order correction. If a (pseudo-)scalar field is directly coupled to curvature invariants, ”hairy” black holes can be generated. The scalar hair is present due to the interaction with the underlined geometry. We seek for a slowly rotating black hole solution dressed with axionic hair and we examine how such a system violates the Null Energy Condition in the region outside the horizon. We study the angular momentum of the axion-black hole system and the behaviour of timelike geodesics around it, leading to a completely new behaviour of the effective potential, which presents a repulsive nature for the counter rotating geodesics near the horizon.	en
heal.advisorName	Μαυρόματος, Νικόλαος	el
heal.committeeMemberName	Κεχαγιάς, Αλέξανδρος	el
heal.committeeMemberName	Μαυρόματος, Νικόλαος	el
heal.committeeMemberName	Αναγνωστόπουλος, Κωσταντίνος	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Εφαρμοσμένων Μαθηματικών και Φυσικών Επιστημών	el
heal.academicPublisherID	ntua
heal.numberOfPages	110 σ.	el
heal.fullTextAvailability	false