Instability and Degeneracy in the BMN Correspondence

TL;DR

This paper investigates the instability of excited string states in the BMN correspondence, revealing that non-degenerate perturbation theory fails with triple trace operators and providing decay widths as new gauge theory data.

Contribution

It introduces a novel analysis of string state instability by applying time-dependent perturbation theory to include effects of triple trace operators.

Findings

Non-degenerate perturbation theory breaks down with triple trace operators.

Decay widths of excited states are calculated from gauge theory.

Results provide new data for comparison with string field theory.

Abstract

Non-degenerate perturbation theory, which was used to calculate the scale dimension of operators on the gauge theory side of the correspondence, breaks down when effects of triple trace operators are included. We interpret this as an instability of excited single-string states in the dual string theory for decay into the continuum of degenerate 3-string states. We apply time-dependent perturbation theory to calculate the decay widths from gauge theory. These widths are new gauge theory data which can be compared with future calculations in light cone string field theory.