A Sharp Existence Theorem for Vortices in the Theory of Branes

We investigate the BPS equations arising from the theory of multi-intersection of D-branes. By using the direct minimization method, we establish sharp existence and uniqueness theorems for multiple vortex solutions of the BPS equations over a doubly periodic domain and over the full plane, respectively. In particular, we obtain an explicit necessary and sufficient condition for the existence of a unique solution for the doubly periodic domain case.