Bubbles in AdS

We investigate loop corrections to the four-point function of identical scalar operators in a four-dimensional large $N$ conformal field theory, holographically dual to AdS with a quartic interaction. We focus on the universal part of the correlator that, at any order in $1/N$, is completely determined by tree-level data. We show how this contribution controls the part of the anomalous dimensions of double-trace operators, that exhibits a characteristic $\log \ell$ dependence at large spin $\ell$. We resum these effects to all orders in $1/N$ and show that they admit a natural effective description in AdS. Finally, by reformulating the problem in Mellin space, we demonstrate that the same contribution corresponds to consecutive unitarity cuts of bubble diagrams in the flat space limit.