Vázquez Ramallo, AlfonsoPenín Ascariz, José Manuel2019-12-172019-12-172019http://hdl.handle.net/10347/20493This thesis is based on the gravity/gauge duality and consists of four different parts. The first part is devoted to the construction of backreacted geometries corresponding to the near brane limit of the D3-D5 brane intersection. The geometries corresponding to the addition of massless and massive flavors and the solution dual to a field theory at non-zero temperature are constructed. The second part focuses on the computation of the spectrum of fluctuations of the Gaiotto-Maldacena geometries. The third part is centered on the addition of brane defects to the Brandhuber-Oz geometry. The fourth part covers the analysis of the integrability of strings in a class of geometries in Massive type IIA supergravity found by Cremonesi and Tomasiello.engAttribution-NonCommercial-NoDerivatives 4.0 Internacionalhttp://creativecommons.org/licenses/by-nc-nd/4.0/gauge/gravity dualityAdS/CFTgravityMaterias::Investigación::22 Física::2212 Física teórica::221212 Teoría cuántica de camposMaterias::Investigación::22 Física::2212 Física teórica::221205 Gravitacióndoctoral thesisopen access