Puzzles at Large N

TL;DR

This paper explores the AdS/CFT correspondence in 2d CFTs, revealing missing higher spin states in AdS supergravity that relate to black hole entropy, highlighting gaps between CFT predictions and supergravity spectra.

Contribution

It uncovers the absence of certain higher spin primary fields in AdS supergravity and links their high mass extension to black hole entropy in five dimensions.

Findings

Missing higher spin states in AdS supergravity spectrum.

High mass extension accounts for extremal black hole entropy.

Discrepancy between CFT predictions and supergravity excitations.

Abstract

We consider the AdS/CFT correspondence in the context of 2d CFT and find that essentially all ``single particle'' primary fields with higher spin, predicted from the CFT side are missing from the Kaluza-Klein excitations of the AdS supergravity. The high mass extension of these missing states gives rise to the macroscopic entropy of extremal 5d black holes.