Cano, Pablo A.Mas Paradís, Quim2024-10-172024-10-172024-06https://hdl.handle.net/2445/215839Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2024, Tutor: Pablo A. CanoIn General Relativity, the no-hair theorem states that the exterior geometry of a black hole is completely determined by its mass, M, charge, Q, and angular momentum, L. In this work, we first revisit the black hole uniqueness theorems within the Einstein-Maxwell theory, which establish the uniqueness of the Reissner-Nordstr¨om metric. We then consider the presence of a probe scalar field in the gravitational theory, located in the vicinity of a black hole. Our goal is to evaluate the validity of the no-hair theorem in this scenario. We establish that all interacting non-singular field solutions must be trivial, provided their squared mass is positive, m2> 0. Subsequently, we find a non-trivial solution in Anti-de Sitter spacetime (where fields with m2< 0 are allowed), which depends on a parameter determined by the field. Thus, we conclude that black hole solutions with scalar hair, which depend on parameters other than M, Q, and L, may exist in this spacetime5 p.application/pdfengcc-by-nc-nd (c) Mas, 2024http://creativecommons.org/licenses/by-nc-nd/3.0/es/Forats negresCamp escalarTreballs de fi de grauBlack holesScalar fieldBachelor's thesesinfo:eu-repo/semantics/bachelorThesisinfo:eu-repo/semantics/openAccess