A Unified View of RS Braneworlds

There are various different descriptions of Randall-Sundrum (RS) braneworlds. Here we present a unified view of the braneworld based on the gradient expansion approach. In the case of the single-brane model, we reveal the relation between the geometrical and the AdS/CFT approach. It turns out that the high energy and the Weyl term corrections found in the geometrical approach merge into the CFT matter correction found in the AdS/CFT approach. We also clarify the role of the radion in the two-brane system. It is shown that the radion transforms the Einstein theory with Weyl correction into the conformally coupled scalar-tensor theory where the radion plays the role of the scalar field.