A thesis for the degree of Doctor of Philosophy defended December 2018.
The PhD School of Science, Faculty of Science, Theoretical Particle Physics and Cosmology, Niels Bohr Institute, University of Copenhagen
Dr. Niels Obers
Dr. Jay Armas
Blackfold and non-AdS Holography
Over the past 20 years we learnt that General Relativity is not "just" a theory that describes the 4 dimensional universe we live in, through the study of cosmology and black holes. It is much more. In fact we discovered that General Relativity can be used as a tool to describe also other physical settings, not just astrophysics and cosmology. As it happened with Quantum Field Theory, which was discovered in the realm of quantum electrodynamics but was later applied in many other branches of physics, so it happened with General Relativity. After the discovery of the AdS/CFT correspondence we learnt that General Relativity is the tool for describing strongly coupled system. This is one of the motivations for studying General Relativity in settings that are different with respect to astrophysics and cosmology.
The first part of this work, in particular chapters 1-2-3, is devoted to studying higher dimensional advanced black holes configurations. They can be useful for understanding more about general relativity, and they can be used, through AdS/CFT correspondence, for studying some strongly coupled Quantum Field Theory. Over the last years, effective theories for black holes, together with numerical methods, have been extremely important for studying gravity in higher dimensions, which is particularly difficult to solve. Among these effective theories, there are the blackfold approach  and the large D expansion .