String Junction from Worldsheet Gauge Theory

TL;DR

This paper investigates three-string junctions using D-string worldsheet gauge theory, interpreting kink solutions as pronged strings, and explores their supersymmetric configurations and interactions on D3-branes.

Contribution

It provides a gauge theory perspective on string junctions, justifies the kink interpretation, and explicitly constructs solutions using the Nahm equation for D3-brane configurations.

Findings

Kink solutions correspond to pronged strings in gauge theory.

Configurations preserve 1/4 supersymmetry with Nahm equation conditions.

String interactions lead to curved trajectories on D3-branes.

Abstract

We study the three-pronged strings (three string junctions) from the point of view of D-string worldsheet gauge theory. We justify interpreting kink solutions in the 2-dimensional gauge theory as pronged strings by examining BPS energy bounds obtained from this theory. When the ends of the pronged string are on D3-branes, the configuration preserves 1/4 supersymmetry with BPS conditions including the Nahm equation. Using solutions of the Nahm equation explicitly, we treat string junction configuration ending on the D3-branes from the viewpoint of the D-string. In particular, when two separated pronged strings end on the same D3-branes, they interact with each other through the D3-branes and the resultant trajectories of three-pronged strings are found to be curved non-trivially.