AdS/CFT on the brane

Abstract

It is widely recognized that the AdS/CFT correspondence is a useful tool to study strongly coupled field theories. On the other hand, Randall-Sundrum (RS) braneworld models have been actively discussed as a novel cosmological framework. Interestingly, the geometrical set up of braneworlds is quite similar to that in the AdS/CFT correspondence. Hence, it is legitimate to seek a precise relation between these two different frameworks. In this lecture, I will explain how the AdS/CFT correspondence is related to the RS braneworld models. There are two different versions of RS braneworlds, namely, the single-brane model and the two-brane model. In the case of the single-brane model, we reveal the relation between the geometrical and the AdS/CFT correspondence approach using the gradient expansion method. It turns out that the high energy and the Weyl term corrections found in the geometrical approach correspond to the CFT matter correction found in the AdS/CFT correspondence approach. In the case of two-brane system, we also show that the AdS/CFT correspondence plays an important role in the sense that the low energy effective field theory can be described by the conformally coupled scalar-tensor theory where the radion plays the role of the scalar field. We also discuss dilatonic braneworld models from the point of view of the AdS/CFT correspondence.