BPS dynamics of the triple ( p, q) string junction

Abstract

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