Gauge Symmetry in Fivebrane Conformal Field Theory

Abstract

String duality provides us with a definition of string theory for large string coupling constant[1,2]. The massless particles of the perturbative spectrum of string theory remain massless for all coupling constant values. However string duality shows there is an additional solitonic set of states, absent in string perturbation theory, which for strong coupling are generically also of low mass. (In special cases the soliton states are massless even for weak coupling constant values.) These additional degrees of freedom have been described in some cases by a world-sheet conformai field theory (cft). One example of this is the D-brane open and closed string perturbation theory whose spectrum is the same as that of closed type II superstrings with Ramond-Ramond solitons[3,4].