Topological defects in gauge theories of open p-branes

We study phase transitions induced by topological defects in compact Abelian gauge theories of open p-branes in (d+1) space-time dimensions. Starting from a massive antisymmetric tensor theory for the open p-branes we show how the condensation of topological defects can lead to a decoupled phase with a massless tensor coupled to closed (p - 1)-branes and a massive tensor coupled to open (p + 1)-branes. We also consider the case, relevant in string theory, in which the boundaries of the p-branes are constrained to live on a Dirichlet n-brane.