String Interactions in PP-Waves

TL;DR

This paper proposes an effective coupling for string interactions in PP-wave spacetimes, smoothly connecting flat space and gauge theory predictions, based on a Matrix String framework.

Contribution

It introduces a new effective coupling formula for string interactions in PP-waves, linking string theory and gauge theory results through a Matrix String perspective.

Findings

Effective coupling $g_{eff}$ interpolates between flat space and gauge theory regimes.

Derived from Matrix String description of PP-wave backgrounds.

Provides a unified understanding of string interactions in different regimes.

Abstract

We argue that string interactions in a PP-wave spacetime are governed by an effective coupling $g_{eff}=g_s(\mu p^+\apm)f(\mu p^+ \apm)$ where $f(\mu p^+ \apm)$ is proportional to the light cone energy of the string states involved in the interaction. This simply follows from generalities of a Matrix String description of this background. $g_{eff}$ nicely interpolates between the expected result ($g_s$) for flat space (small $\mu p^+\apm$) and a recently conjectured expression from the perturbative gauge theory side (large $\mu p^+\apm$).