BORN-INFELD PARTICLES AND DIRICHLET P-BRANES

Born-Infeld theory admits finite energy point particle solutions with delta-function sources, BIons. I discuss their role in the theory of D irichlet p-branes as the ends of strings intersecting the brane when t he effects of gravity are ignored. There are also topologically non-tr ivial electrically neutral catenoidal solutions looking like two p-bra nes joined by a throat. The general solution is a nonsingular deformat ion of the catenoid if the charge is not too large and a singular defo rmation of the BIon solution for charges above that limit. The interme diate solution is BPS and Coulomb-like. Performing a duality rotation we obtain monopole solutions, the BPS limit being a solution of the ab elian Bogolmol'nyi equations. The situation closely resembles that of sub and super extreme black-brane solutions of the supergravity theori es. I also show that certain special Lagrangian submanifolds of C-p, p = 3, 4, 5, may be regarded as supersymmetric configurations consistin g of p-branes at angles joined by throats which are the sources of glo bal monopoles. Vortex solutions are also exhibited. (C) 1998 Published by Elsevier Science B.V.