On Genus-one String Amplitudes on $AdS_5 \times S^5$
Luis F. Alday
TL;DR
This work probes non-planar corrections to the stress-tensor four-point correlator in N=4 SYM at strong coupling, recasting the genus-one AdS amplitude in Mellin space. It develops a unified framework where loop effects split into loop supergravity, governed by simultaneous poles in $s,t,u$, and stringy corrections, determined from tree-level data, via a constructive unitarity-inspired procedure. UV divergences are interpreted as Mellin sums that require regularization, with polynomial ambiguities constrained by analyticity in spin and the flat-space limit, which matches the known genus-one 10D string amplitude. The results illuminate the AdS/CFT dictionary at genus one, clarify the flat-space limit, and pave the way for extensions to broader correlators and higher-genus corrections within the Mellin-Polyakov bootstrap program.
Abstract
We study non-planar correlators in ${\cal N}=4$ super-Yang-Mills in Mellin space. We focus in the stress tensor four-point correlator to order $1/N^4$ and in a strong coupling expansion. This can be regarded as the genus-one four-point graviton amplitude of type IIB string theory on $AdS_5 \times S^5$ in a low energy expansion. Both the loop supergravity result as well as the tower of stringy corrections have a remarkable simple structure in Mellin space, making manifest important properties such as the correct flat space limit and the structure of UV divergences.
