Vacuum energy and dilaton tadpole for the unoriented closed bosonic string

Publisher Website
Google Scholar
Abstract
In oriented-closed-bosonic-string theory a dilaton tadpole (and vacuum energy) first develops at the one-loop level from performing the path integration over manifolds with the topology of the torus. We show that in the case of the unoriented closed bosonic string the leading contribution to the dilaton tadpole arises at the tree level from the path integral over manifolds with the topology of the projective plane. We explicitly compute the vacuum energy and the dilaton tadpole using Polyakov’s formulation of string theory.