Holographic three-point functions for short operators

TL;DR

This paper computes holographic three-point functions for short operators in N=4 super Yang-Mills at strong coupling, using saddle point approximations and flat-space vertex operators, with implications for Konishi operators.

Contribution

It introduces a method to evaluate three-point functions for short string states by approximating vertex operators and analyzing interaction regions in AdS space.

Findings

Interaction position determined by saddle point conservation laws

Approximation of string vertex operators as flat-space operators

Unique scalar vertex operator choice for primary operators

Abstract

We consider holographic three-point functions for operators dual to short string states at strong coupling in N=4 super Yang-Mills. We treat the states as point-like as they come in from the boundary but as strings in the interaction region in the bulk. The interaction position is determined by saddle point, which is equivalent to conservation of the canonical momentum for the interacting particles, and leads to conservation of their conformal charges. We further show that for large dimensions the rms size of the interaction region is small compared to the radius of curvature of the AdS space, but still large compared to the string Compton wave-length. Hence, one can approximate the string vertex operators as flat-space vertex operators with a definite momentum, which depends on the conformal and R-charges of the operator. We then argue that the string vertex operator dual to a primary operator is chosen by satisfying a twisted version of Q^L=Q^R, up to spurious terms. This leads to a unique choice for a scalar vertex operator with the appropriate charges at the first massive level. We then comment on some features of the corresponding three-point functions, including the application of these results to Konishi operators.