Solutions and Democratic Formulation of Supergravity Theories in Four Dimensions

Resumen

Introduction This thesis deals with four-dimensional Supergravity theories and solutions thereto. Supergravities are very interesting theories for many reasons. In this introduction we shall give a short overview of the main motivations for introducing Supersymmetry, Supergravity and, last but not least, Superstring Theory. We will briefly describe how supersymmetry might help to address some problems of the Standard Model, then we shortly summarize some basic facts about Superstring Theory and its low energy limit, Supergravity. In the second part of this introduction we will discuss gaugings of Supergravity and its implications, focussing on the so-called tensor hierarchy. In the section 1.3 we will describe schematically how to find supersymmetric solutions to a given Supergravity theory. The outline of this thesis is given in the last section of this introduction.