Black hole is a theoretical testing ground for understanding quantum gravity. The fact discovered by J.Bekenstein and S. Hawking that black holes are thermodynamic objects having temperature, entropy, and emitting thermal radiation provides us a strong guide for studying the black holes and their microscopic quantum structure. 

Our group aims at studying the quantum nature of thermodynamics of the black holes arising in string theory. We analyze the problems from both macroscopic and microscopic directions, which are respectively via supergravities and corresponding dual supersymmetric gauge theories given by AdS/CFT correspondence. We develop ways of treating quantum aspects of back hole entropy. Some of the approaches allow us to exactly capture the quantum effects on black hole entropy in a systematic way, by which we provide precise tests for string theory as a candidate for a theory of quantum gravity. We further study various thermodynamic properties of black holes or extended objects in different ensembles.