  Witten couples the open topological B-model to a holomorphic vector bundle by
adding to the boundary of the worldsheet a Wilson loop for an integrable
connection on the bundle. Using the descent procedure for boundary vertex
operators in this context, I generalize this construction to write a worldsheet
coupling for a graded vector bundle with an integrable superconnection. I then
compute the open string vertex operators between two such boundaries. A theorem
of J. Block gives that this is equivalent to coupling the B-model to an
arbitrary object in the derived category.
