Unmixing Supergravity
F. Aprile, J. M. Drummond, P. Heslop, H. Paul
TL;DR
The paper addresses degeneracy in the double-trace spectrum of N=4 SYM at large N by resolving mixing between free-field and tree-level supergravity contributions using four-point functions of half-BPS operators. It employs a combination of Mellin-space tree-level supergravity, GL(2|2) superconformal blocks, and a novel bosonised approach to derive a remarkably simple structure for anomalous dimensions and OPE coefficients, including closed-form expressions for representations [n,0,n]. The resulting framework yields negative anomalous dimensions with a universal, orthogonal mixing matrix tilde{c}, enabling predictions for leading O(1/N^2) data and informing potential higher-loop corrections. The work clarifies the large-N holographic spectrum, provides a practical method to extract strong-coupling data from correlators, and suggests broader applicability to other holographic CFTs with KK towers of KK modes on S^5.
Abstract
We examine the double-trace spectrum of $\mathcal{N} = 4$ super Yang-Mills theory in the supergravity limit. At large $N$ double-trace operators exhibit degeneracy. By considering free-field and tree-level supergravity contributions to four-point functions of half-BPS operators we resolve the degeneracy for a large family of double-trace operators. The mixing problem reveals a surprisingly simple structure which allows us to obtain their three-point functions at leading order in the large $N$ expansion as well as their leading anomalous dimensions.
