On a Large N Degeneracy in N=4 SYM and the AdS/CFT Correspondence

TL;DR

This paper investigates the four-point correlator of 1/2-BPS operators in N=4 SYM, revealing a surprising degeneracy at one loop that contrasts with supergravity predictions, with implications for AdS/CFT.

Contribution

It provides explicit one-loop and supergravity calculations of the correlator, uncovering a degeneracy in the amplitude functions that challenges existing expectations.

Findings

One-loop results show the two amplitude functions coincide.

Supergravity results show the two functions are different.

Degeneracy at one loop may have implications for AdS/CFT correspondence.

Abstract

We study the four-point correlator of 1/2-BPS operators of weight 4 in N=4 SYM, which are dual to massive KK modes in AdS_5 supergravity. General field-theoretic arguments lead to a partially non-renormalized form of the amplitude that depends on two a priori independent functions of the conformal cross-ratios. We explicitly compute the amplitude in the large N limit at one loop (order g^2) and in AdS_5 supergravity. Surprisingly, the one-loop result shows that the two functions determining the amplitude coincide while in the supergravity regime they are distinctly different. We discuss the possible implications of this perturbative degeneracy for the AdS/CFT correspondence.