Quantum Gravity in Three Dimensions from Higher-Spin Holography

In this thesis, I explore various aspects of quantum gravity in three dimensions from the perspective of higher-spin holography in anti-de Sitter spacetime. The bulk theory is a higher-spin Vasiliev gravity theory of which topological sector can be described by a Chern-Simonstheory equipped with some suitable Lie (super-)algebra, whereas the boundary conformal field theory is conjectured to be a coset minimal model which contains W symmetries. I present new black hole solutions and investigate the thermodynamics of these solutions, inparticular, I establish a relationship among black hole thermodynamics, asymptotic symmetries and W algebras. I also construct new conical defect solutions, supersymmmetric RG flow solutions in the bulk gravity theories, and present the bulk-boundary propagator for scalar elds interacting with a higher-spin black hole. The main examples used in this thesis are illustrated in the framework of SL(N) and SL(N|N-1) Chern-Simons theories, and I point out how these new solutions can be used to yield some insights into the nature of quantum gravity