Strings in flat space and pp waves from ${\cal N}=4$ Super Yang Mills

TL;DR

This paper demonstrates how the string spectrum in flat space and pp-waves can be derived from large N limits of ${ m N}=4$ super Yang Mills, connecting gauge theory diagrams to string theory spectra.

Contribution

It shows the derivation of string spectra from gauge theory by summing specific planar diagrams and introduces a matrix model for pp-waves in M-theory.

Findings

Reproduces string spectra from gauge theory diagrams.

Provides heuristic reasoning for diagram neglect.

Presents a matrix model for pp-wave DLCQ description.

Abstract

We explain how the string spectrum in flat space and pp-waves arises from the large $N$ limit, at fixed $g^2_{YM}$, of U(N) ${\cal N} =4$ super Yang Mills. We reproduce the spectrum by summing a subset of the planar Feynman diagrams. We give a heuristic argument for why we can neglect other diagrams. We also discuss some other aspects of pp-waves and we present a matrix model associated to the DLCQ description of the maximally supersymmetric eleven dimensional pp-waves.