Supersymmetric world-volume action for non-BPS D-branes

Abstract

We construct the world-volume action for non-BPS D-branes in type II string theories. This action is invariant under all the unbroken supersymmetries in the bulk, but these symmetries are realised as spontaneously broken symmetries in the world-volume theory. Coupling of this action to background supergravity fields is straightforward. We also discuss the fate of the U(l) gauge field on the D-brane world-volume after tachyon condensation.