Semiclassical strings and AdS/CFT

TL;DR

This paper explores the AdS/CFT duality focusing on semiclassical string states with large quantum numbers, highlighting the effective action approach and its connection to integrable spin chains in N=4 super Yang-Mills theory.

Contribution

It reviews the coherent-state effective action method and its relation to sigma models and integrable spin chains in the context of AdS/CFT correspondence.

Findings

Leading-order energy and anomalous dimension matching

Effective action approach unifies string and gauge theory descriptions

Discussion of higher-order correction implications

Abstract

We discuss AdS/CFT duality in the sector of ``semiclassical'' string states with large quantum numbers. We review the coherent-state effective action approach, in which similar 2d sigma model actions appear from the AdS_5 x S^5 string action and from the integrable spin chain Hamiltonian representing the N=4 super Yang-Mills dilatation operator. We consider mostly the leading-order terms in the energies/anomalous dimensions which match but comment also on higher-order corrections.