PhD ceremony Mr. A. Borghese: Cosmological and holographic applications of supergravity

PhD ceremony: Mr. A. Borghese, 11.00 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Cosmological and holographic applications of supergravity

Promotor(s): prof. E.A. Bergshoeff

Faculty: Mathematics and Natural Sciences

In this thesis we study supergravity theories in four and five space-time dimensions. The attention is focussed on their application to the fields of cosmology and holography.

The thesis contains an introduction to superalgebras, globally supersymmetric field theories and supergravity. The phenomenon of supersymmetry breaking is analysed in detail. All the results are shown, after the introduction, in two separate parts of the thesis: one related to cosmology and the other related to holography.

In the cosmology part we first review observational evidences regarding our universe. We then describe the standard model of cosmology, the so called concordance model (inflation plus CDM). The remainder of this part regards the embedding of the concordance model in specific supergravity theories. We first analyse the constraints on inflation coming from the requirement that the effective field theory of inflation should be a minimal (N=1) four dimensional supergravity. Secondly, we study the vacuum structure and stability of (half-)maximal supergravity (N=4,8) in four dimensions. We are particularly interested in the search for de Sitter vacua (those vacua describe a universe expanding in an accelerated manner). We obtain our results studying particular scalar fields, called sGoldstinos, which are singled out by supersymmetry breaking.

In the second part, after a short introduction to holography, we study the vacuum structure and stability of a new class of maximal supergravities in four dimensions. Finally we describe a specific five dimensional supergravity which is related holographically to a four dimensional supersymmetric field theory displaying a superconducting phase.