Worldsheet Instantons and a Null String Limit of Born-Infeld Theory
arXiv:hep-th/0702173 · doi:10.1140/epjc/s10052-007-0474-5
Abstract
For a superstring theory in four spacetime dimensions, we propose a modification of the Born-Infeld action that possesses a well-defined tensionless limit. We interpret this as describing the effective target space dynamics of null strings on a D3-brane. We argue that such a modification can be induced by nonperturbative contributions from instantons in the worldsheet sigma-model describing string propagation on the brane.
11 pages; Comments and references added