Non-supersymmetric branes

We discuss how to incorporate non-supersymmetric branes in compactifications of type II string theories. We particularly focus on flux compactifications on SU(3) × SU(3) structure manifolds to four dimensions, so that a linear $$ \mathcal{N} $$ = 1 supersymmetry is spontaneously broken by spacetime filling Dp-branes. Anti-Dp-branes are a very special subset of such branes but our analysis is generic. We show that the backreaction of non-supersymmetric branes can be incorporated into the standard 4d $$ \mathcal{N} $$ = 1 supergravity by including a nilpotent chiral multiplet. Supersymmetry in such setups is always spontaneously broken and non-linearly realized. In particular this means that, contrary to what was previously thought, brane supersymmetry breaking cannot be simply described by a D-term in 4d $$ \mathcal{N} $$ = 1 supergravity theories.