Non-Supersymmetric Black Holes: A Step Toward Quantum Gravity

One of the greatest challenges of modern theoretical physics is to find a quantum theory of gravity that could unify general relativity and quantum mechanics. The microscopic understanding of black holes plays an essential role in pursuing this goal for its unique connection between gravity and quantum effects. Despite the remarkable progress that has been made towards this direction, most developments rely heavily on supersymmetry and elude more realistic non-supersymmetric (nonBPS) black holes. This thesis is to improve this situation and develop both the macroscopic and microscopic sides of nonBPS black holes. In the first part of this thesis, we study a special class of nonBPS black hole solutions in supergravity theories and compute logarithmic corrections to black hole entropy. We find that the correction is universal and independent of black hole parameters only when the number of supercharges $mathcal{N}geq6$. In the second part, we compute the spectrum of extremal nonBPS black holes introduced in the previous part by studying supergravity on their near-horizon geometry. We find that the spectrum exhibits significant simplifications even though supersymmetry is completely broken and we interpret our results in the framework of the AdS/CFT correspondence. In the final part, we analyze AdS$_5$ black holes that are nearly supersymmetric. They depart from the BPS limit either by having nonzero temperature or by violating a constraint on potentials. We study the thermodynamics of these deformations and their interplay. We discuss microscopic computations of BPS black hole entropy in $mathcal{N}=4$ supersymmetric Yang-Mills theory and generalize the arguments to compute entropy of nearBPS black holes, which agrees with results from the gravity side.PhDPhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/163058/1/zengywx_1.pd