SUPERSYMMETRIC OBJECTS IN GAUGED SUPERGRAVITIES

The formulation of a unified description of fundamental interactions has always been the most relevant and intriguing challenge in physics. To this end, a microscopic description of gravity and its consequent unification to electromagnetic and nuclear forces is needed. A theory realizing such a framework would be called theory of quantum gravity and, so far, the only consistent setup which seeks to realize this purpose is given by string theory. In this context, the divergences appearing in classical gravity theory are resolved at high energies in terms of contributions coming from the physics of extra dimensions. From this point of view, in order to gain the stability of higher-dimensional objects, like strings and branes, the formulation of quantum theories of gravity requires supersymmetry. These fundamental extended objects give rise, at low energies, to supersymmetric systems that are strongly coupled to gravity like, for example, black holes. The theories describing the low-energy regime of objects living at higher dimensions are called supergravity theories and constitute the general setup of this thesis. These are classical interacting theories of gravity characterized by local supersymmetry. In this context, the description of supersymmetric objects is realized by classical solutions of the equations of motion and the link with high energies is controlled by the AdS/CFT correspondence and by string compactifications. Starting from this general framework, in this thesis the results published during the three years of doctoral studies are presented. Three particular supergravity realizations in four- five- and seven dimensions are considered and discussed in relation to the physics of the supersymmetric objects arising from them. The analysis of the results in terms of the underlying microscopic theories is also developed with particular emphasis on string compactifications, giving rise to the three supergravities considered, and on the holographic interpretation, explaining the origin of the supersymmetric solutions presented in terms of non-perturbative states of string theory.