Aspects Of Black Holes In Extended Theories Of Gravity
Date
2025-04-16
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0009-0009-2762-5063
Type
Thesis
Degree Level
Doctoral
Abstract
This thesis explores deviations from general relativity to address its limitations and connect gravity with quantum mechanics. Motivated by the need for quantum gravity frameworks and the challenge of explaining the accelerated expansion of the universe without dark energy, we examine modified theories such as f(R) and f(T ) gravity.
Significant contributions include the study of holographic dualities, particularly between rotating black holes and conformal field theories, which reveal hidden symmetries and provide deeper insights into black hole thermodynamics and quantum phenomena. We present several new results in the context of black holes in modified theories of gravity. First, we show that non- extremal charged rotating black holes in quadratic f(T ) gravity are holographically dual to two distinct hidden conformal field theories, which can be unified into a general theory generated by SL(2, Z) modular group. Additionally, we find new exact solutions for rotating black holes in f(R) gravity in the presence of imperfect fluid and under Lorentz boost transformation. These solutions are also holographically dual to a hidden conformal field theory. We propose a conjecture that two identical rotating black holes in f(R) theory can be distinguished by their dual conformal temperatures and mode numbers.
We further explore dynamical black hole solutions in higher dimensional Einstein-Maxwell-dilaton theory with arbitrary cosmological constants. These non-stationary solutions are almost conformally regular and describe coalescing black holes. We discuss the properties of these solutions, which can be asymptotically de-Sitter, anti-de-Sitter, or flat, depending on the values of the coupling constants.
By identifying new solutions, analyzing their properties, and establishing holographic connections, this thesis advances the study of general relativity extensions, offering valuable tools for unifying gravity with quantum theory.
Description
Keywords
General Relativity, Black Holes, Modified Theories of Gravity, Einstein-Maxwell-dilaton Theory, Higher Dimensions, f(R) gravity, f(T) gravity, Hidden Conformal Symmetries, Holographic Duality
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Physics and Engineering Physics
Program
Physics