New aspects of the BMN correspondence beyond the planar limit

TL;DR

This paper investigates the non-planar sector of the BMN correspondence in AdS/CFT, revealing discrepancies with previous results and gauge theory predictions, and highlighting the need for more comprehensive approaches beyond impurity-conserving channels.

Contribution

It provides a detailed perturbative analysis of energy shifts in non-planar BMN states, uncovering unexpected results that challenge existing assumptions and suggest limitations of current truncation methods.

Findings

Discrepancies with earlier leading order computations

Presence of half-integer powers of the gauge coupling

Impurity-conserving truncation is insufficient for conclusive tests

Abstract

Motivated by recent disagreements in the context of AdS/CFT, we study the non-planar sector of the BMN correspondence. In particular, we reconsider the energy shift of states with two stringy excitations in light-cone string field theory and explicitly determine its complete perturbative contribution from the impurity-conserving channel. Surprisingly, our result neither agrees with earlier leading order computations, nor reproduces the gauge theory prediction. More than that, it features half-integer powers of the effective gauge coupling $\lambda'$ representing a qualitative difference to gauge theory. Based on supersymmetry we argue that the above truncation is not suited for conclusive tests of the BMN duality.