Worldsheet Dynamics of String Junctions

TL;DR

This paper investigates the worldsheet behavior of string junctions in type IIB string theory, revealing boundary conditions, conserved supercharges, and spectral properties of string lattices, advancing understanding of string network dynamics.

Contribution

It provides a detailed analysis of string junction scattering, boundary conditions, and conserved supercharges, and computes the band spectrum of string lattices, which is a novel contribution.

Findings

Certain field combinations satisfy Dirichlet or Neumann conditions.

The worldsheet theory preserves eight supercharges.

Band spectra of simple string lattices are obtained.

Abstract

We analyze scattering of string modes at string junctions of type IIB string theory. In the infrared limit, certain orthogonal linear combinations of the fields on the different strings satisfy either Dirichlet or Neumann boundary conditions. We confirm that the worldsheet theory of a general string network has eight conserved supercharges in agreement with target space BPS considerations. As an application, we obtain the band spectrum of some simple string lattices.