Dbranes and physical states
Abstract
States obtained by projecting boundary states, associated with Dbranes, to fixed mass level and momentum generically define nontrivial cohomology classes. For onshell states the cohomology is the standard one, but when the states are off shell the relevant cohomology is defined using a BRST operator with ghost zeromodes removed. The zeromomentum cohomology falls naturally into multiplets of SO( D  1, 1). At the massless level, a simple set of Dbrane configurations generates the full set of zeromomentum states of standard ghost number, including the discrete states. We give a general construction of offshell cohomology classes, which exhibits a nontrivial interaction between left and rightmovers that is not seen in onshell cohomology. This includes, at higher mass levels, states obtained from typical Dbrane boundary states as well as states with a more intricate ghost dependence.
 Publication:

Nuclear Physics B
 Pub Date:
 February 1997
 DOI:
 10.1016/S05503213(96)004750
 arXiv:
 arXiv:hepth/9607113
 Bibcode:
 1997NuPhB.483..248R
 Keywords:

 High Energy Physics  Theory
 EPrint:
 22 pages, harvmac, no figures