Motivated by the results of Hashimoto and Taylor, we perform a detailed study of the mass spectrum of the non-abelian Born-Infeld theory, defined by the symmetrized trace prescription, on tori with constant magnetic fields turned on. Subsequently, we compare this for several cases to the mass spectrum of intersecting D-branes. Exact agreement is found in only two cases: BPS configurations on th...

In this thesis I present applications of the Born-Infeld action to the description of Dbranes, mostly in the context of type IIB string theory. I briefly review the relevant aspects of the general formalism, including the efforts toward generalization of this action to the non-Abelian case. In the second Chapter I present the construction of a fundamental string attached to a threebrane, whereb...

The field equations associated with the Born-Infeld-Einstein action including matter are derived using a Palatini variational principle. Scalar, electromagnetic, and Dirac fields are considered. It is shown that an action can be chosen for the scalar field that produces field equations identical to the usual Einstein field equations minimally coupled to a scalar field. In the electromagnetic an...

Born-Infeld theory is formulated using an infinite set of gauge fields, along the lines of McClain, Wu and Yu. In this formulation electromagnetic duality is generated by a fully local functional. The resulting consistency problems are analyzed and the formulation is shown to be consistent. Email address: [email protected]. Supported by NFR.

We propose a formula for the effective action of Matrix Theory which successfully reproduces a large class of Born-Infeld type D-brane probe actions. The formula is motivated by demanding consistency with known results, and is tested by comparing with a wide range of source-probe calculations in supergravity. In the case of D0-brane sources and Dp-brane probes, we study the effect of boosts, ro...

All solutions of the no-birefringence conditions for nonlinear electrodynamics are found. In addition to known Born-Infeld and Plebanski cases, we find a ``reverse Born-Infeld'' case, which has limit Plebanski, an ``extreme-Born-Infeld'' arises as Lagrangian constraint. Only weak-field limit, only extreme-Born Infeld avoid superluminal propagation in constant electromagnetic backgrounds, but al...