BPS Dynamics of Triple (p,q) String Junction

TL;DR

This paper investigates the dynamics of triple junctions of (p,q) strings in Type IIB string theory, confirming BPS properties, analyzing fluctuations, and proposing effective descriptions and potential bound states in M-theory.

Contribution

It provides a detailed analysis of BPS conditions, force balance, and low-energy effective descriptions of (p,q) string junctions, including novel insights into their fluctuations and possible bound states.

Findings

Tension and mass density match BPS formulas.

Junction fluctuations agree with harmonic analysis.

Potential for evanescent bound-states in M-theory context.

Abstract

We study dynamics of triple junction of (p,q) strings in Type IIB string theory. We probe tension and mass density of (p,q) strings by studying harmonic fluctuations of the triple junction. We show that they agree perfectly with BPS formula provided suitable geometric interpretation of the junction is given. We provide a precise statement of BPS limit and force-balance property. At weak coupling and sufficiently dense limit, we argue that (p,q)-string embedded in string network is a `wiggly string', whose low-energy dynamics can be described via renormalization group evolved, smooth effective non-relativistic string. We also suggest the possibility that, upon Type IIB strings are promoted to M-theory membrane, there can exist `evanescent' bound-states at triple junction in the continuum.