Ungauged and gauged Supergravity Black Holes: results on U-duality
Year: 2012
Type: dissertation
Abstract: Extremal black holes are states in the non-perturbative spectrum of Supergravity theories. They may be charged under abelian fields and in this case give rise to an effective potential for the scalars. This, in addition, is responsible for the occurrence of an attractor mechanism: extremal solutions are determined by critical points of the effective potential. This implies that their supersymmetric features rely only on the algebraic properties of the electric-magnetic duality group. In this thesis black holes solutions and their properties under duality transformations are analyzed in extended Supergravity theories in four dimensions. An introductory part reviews the construction of electric-magnetic duality invariant theories and describes the symplectic covariant formalism both in the case of N=2 and N>2 Supergravity theories. The attractor mechanism and black hole first order formalism are also reviewed. The thesis than proceeds with the discussion of original results. First I discuss the ungauged N=8 theory and show how the supersymmetric properties of black hole duality orbits are manifest, once the proper representations of vectors and scalar fields in different symplectic frames is chosen, according to the algebraic branching of the orbit with respect to the duality group. In particular, one of these cases corresponds to the Kaluza-Klein reduction of the theory from five dimensions, as it can be seen from the relation between the central charge in four and five dimensions. Explicit computations are possible if one restricts the solutions to the stu-truncation. Then I present static dyonic black holes in the context of N=2 U(1) gauged supergravity in four dimensions, with AdS4 asymptotic geometry. It is shown that the flow of scalar fields and metric warp factors is governed by first order equations that can be derived for a general U(1) gauging potential. Explicit examples are finally presented, which only preserve up to half of the supersymmetry and thus evade previous no-go theorems
Author: Alessandra Gnecchi
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W25255622