Boundary states for branes with non trivial homology in constant closed and open background
Abstract
Description
For the bosonic string on the torus we compute boundary states describing branes with not trivial homology class in presence of constant closed and open background. It turns out that boundary states with non trivial open background generically require the introduction of non physical ``twisted'' closed sectors, that only $F$ and not ${\cal F}=F+B$ determines the geometric embedding for $Dp$ branes with $p<25$ and that closed and open strings live on different tori which are relatively twisted and shrunk. Finally we discuss the T-duality transformation for the open string in a non trivial background.
24 pages; v2 Added some references and clarified some points
24 pages; v2 Added some references and clarified some points