Estudos sobre buracos negros em cenários com nuvem de cordas e quintessência, na relatividade geral e na gravitação de Lovelock

Abstract

In this thesis, we study some configurations of black holes with quintessence and/or cloud of strings in general relativity and in Lovelock gravity. We begin with a short review of the theory which bases the subsequent results, namely, black holes in general relativity, some aspects of its thermodynamics and Lovelock gravity. In the sequence, we discuss the Newman-Janis method and some aspects related to the gravitational Casimir effect, as well as we consider dark energy models, in particular the cosmological constant and the quintessence. In the context of general relativity, we study the black hole thermodynamics in the Letelier spacetime with quintessence, we obtain the solution corresponding to the Reissner-Nordström black hole with quintessence and cloud of strings, we study some aspects of its thermodynamics and calculate its quasinormal modes. Adding the contribution of the cosmological constant to this configuration, we analyze the thermodynamics, criticality and, assuming that the system is analogous to a heat engine, we calculate its efficiency. We study also the solutions corresponding to a Kerr black hole with quintessence and a Kerr-Newman-AdS black hole with quintessence and a cloud of strings. In the context of the Lovelock gravity, we investigate the Casimir effect nearby a static black hole. In this modified theory of gravity, we study the black holes surrounded by quintessence and a cloud of strings. Finally, the black holes with quintessence or a cloud of strings are analyzed in the pure Lovelock gravity. We verify that the external matter-energy contents give rises to important geometrical effects in the black holes spacetimes and that the results obtained in the Lovelock gravity are reduced to the ones in general relativity in the weak field limit.