The Off-Shell Boundary State and Cross-Caps in the Genus Expansion of String Theory
Abstract
Description
We use the boundary state formalism for the bosonic string to calculate the emission amplitude for closed string states from particular D-branes. We show that the amplitudes obtained are exactly the same as those obtained from the world-sheet sigma model calculation, and that the construction enforces the requirement for integrated vertex operators, even in the off-shell case. Using the expressions obtained for the boundary state we propose higher order terms in the string loop expansion for the background considered.
28 pages, 0 figures
28 pages, 0 figures