Boundary state in open string channel and open/closed string field theory

Hiroshi Isono, Yutaka Matsuo

Published 2005-11-21, updated 2005-12-12Version 3

We generalize the idea of boundary states to open string channel. They describe the emission and absorption of the open string in the presence of intersecting D-branes. We study the algebra between such states under the star products of string field theory and confirm that they are projectors in a generalized sense. Based on this observation, we propose a modular dual description of Witten's open string field theory which seems to be an appropriate set-up to study D-branes by string field theory.