On non-abelian generalisation of Born-Infeld action in string theory

Abstract

We show that the part of the tree-level open string effective action for the non-abelian vector field which depends on the field strength but not on its covariant derivatives, is given by the symmetrised trace of the direct non-abelian generalisation of the Born-Infeld invariant. We discuss applications to D-brane dynamics.

13 pages, harvmac. Some confusion about instanton matrix model solutions corrected (string solution is interpreted as a D-string bound to a large number of D-instantons)