String Theory, AdS/CFT and Quantum Gravity - Lecture 3 | Horatiu Nastase

In this series of lectures I will explore how the AdS/CFT correspondence helps us understand Quantum Gravity. As AdS/CFT is based on string theory, in the first lecture I will describe the main aspects of supergravity and string theory. In the second lecture, I will describe the main example of the AdS/CFT correspondence, N=4 SYM vs. string theory in the AdS_5xS^5 background, and the variety of nontrivial tests it has passed, including at nontrivial coupling g_s and string length \alpha'. In the third lecture, I will describe the generalizations to gauge/gravity dualities, within string theory ("top-down") and outside ("bottom-up"), and how quantum strings (as opposed to fields for particles) are obtained in the pp wave correspondence, from spin chains. In the fourth lecture, I will describe how purely quantum gravitational effects (at strong coupling) are obtained from field theory in holographic cosmology, a phenomenological application of AdS/CFT to cosmology, leading to an alternative, strongly coupled version, of inflation.