Non-Abelian Structures in BSFT and RR couplings

Abstract

In this talk we show that the tachyon annihilation combined with an approximation, in which string theory non-commutativity structure is captured by the algebra of differential operators on space-time, gives a unified point of view on: non-Abelian structures on $D$-branes; all lowest energy excitations on $D$-branes; all RR couplings in type II string theory.