(F,Dp) bound states from the boundary state

Abstract We use the boundary state formalism to provide the full conformal description of (F,D p ) bound states. These are BPS configurations that arise from a superposition of a fundamental string and a D p -brane, and are charged under both the NS–NS antisymmetric tensor and the ( p +1)-form R–R potential. We construct the boundary state for these bound states by switching on a constant electric field on the world-volume of a D p -brane and fix its value by imposing the Dirac quantization condition on the charges. Using the operator formalism we also derive the Dirac–Born–Infeld action and the classical supergravity solutions corresponding to these configurations.