Flat-space scattering and bulk locality in the AdS/CFT correspondence

TL;DR

This paper explores how flat-space scattering amplitudes can be derived from AdS/CFT correspondence, addressing bulk locality issues through the behavior of the S-matrix and CFT correlators in the large radius limit.

Contribution

It provides a detailed analysis of translating CFT correlators into flat-space scattering amplitudes and discusses criteria for approximate bulk locality in this context.

Findings

Flat-space amplitudes are obtained via projection of CFT correlators onto AdS normal modes.

Growth bounds on amplitudes at high energies relate to bulk locality.

Reproduction of semiclassical gravitational scattering supports the flat-space limit.

Abstract

The large radius limit in the AdS/CFT correspondence is expected to provide a holographic derivation of flat-space scattering amplitudes. This suggests that questions of locality in the bulk should be addressed in terms of properties of the S-matrix and their translation into the conformal field theory. There are, however, subtleties in this translation related to generic growth of amplitudes near the boundary of anti de-Sitter space. Flat space amplitudes are recovered after a delicate projection of CFT correlators onto normal-mode frequencies of AdS. Once such amplitudes are obtained from the CFT, possible criteria for approximate bulk locality include bounds on growth of amplitudes at high energies and reproduction of semiclassical gravitational scattering at long distances.