Multi-particle correlators with higher KK modes I: a bootstrap approach
Francesco Aprile, Stefano Giusto, Rodolfo Russo, Joao Vilas Boas
TL;DR
This work develops a double-particle bootstrap at tree level in AdS$_5 imes$S$^5$ to compute four-point holographic correlators with one external double-particle half-BPS operator and three single-particle half-BPS operators in ${ m N}=4$ SYM at large $N$ and large 't Hooft coupling. By exploiting the OPE data of double-particle operators and the partial non-renormalization theorem, the authors fix the connected $O(1/N^3)$ contribution as a sum of AdS contact diagrams (D-functions), despite degeneracies in the double-particle spectrum. They validate the results by matching to the double-particle limit of recently conjectured five-point tree-level single-particle correlators with arbitrary KK levels, providing strong evidence for the Fernandes:2025eqe proposal. The paper also develops a Mellin-space perspective, deriving explicit tree-level Mellin amplitudes for these correlators and analyzing their flat-space limits, while extending the analysis to broader families of double-particle operators and higher extremality. Overall, the results deepen our understanding of multi-particle operators in holographic CFTs and connect four- and five-point data in a concrete, testable framework.
Abstract
We bootstrap tree-level supergravity four-point correlators on AdS$_5\times$S$^5$ with one external half-BPS double-particle operator and three half-BPS single-particle operators. Our only input is the consistency of the operator product expansion of $SU(N)$ ${\cal N} = 4$ super Yang-Mills theory at large $N$ and large 't Hooft coupling. Even though the leading order OPE does not close on double-particle operators, but involves triple-particle operators, the CFT data of the double-particle operators, both long and protected, is sufficient to uniquely fix the correlators. We then verify that our results for the four-point correlators with one double-particle and three single-particle operators are reproduced by the appropriate double-particle limit of the five-point tree-level correlators of single-particle operators, with arbitrary Kaluza-Klein levels, recently conjectured in arXiv:2507.14124. Our study thus provides further evidence for the latter result.
