36 research outputs found
Tensor Constructions of Open String Theories II: Vector bundles, D-branes and orientifold groups
A generalized Chan-Paton construction is presented which is analogous to the
tensor product of vector bundles. To this end open string theories are
considered where the space of states decomposes into sectors whose product is
described by a semigroup. The cyclicity properties of the open string theory
are used to prove that the relevant semigroups are direct unions of Brandt
semigroups. The known classification of Brandt semigroups then implies that all
such theories have the structure of a theory with Dirichlet-branes. We also
describe the structure of an arbitrary orientifold group, and show that the
truncation to the invariant subspace defines a consistent open string theory.
Finally, we analyze the possible orientifold projections of a theory with
several kinds of branes.Comment: 11 pages, LaTe
On Second-Quantized Open Superstring Theory
The SO(32) theory, in the limit where it is an open superstring theory, is
completely specified in the light-cone gauge as a second-quantized string
theory in terms of a ``matrix string'' model. The theory is defined by the
neighbourhood of a 1+1 dimensional fixed point theory, characterized by an
Abelian gauge theory with type IB Green-Schwarz form. Non-orientability and
SO(32) gauge symmetry arise naturally, and the theory effectively constructs an
orientifold projection of the (weakly coupled) matrix type IIB theory (also
discussed herein). The fixed point theory is a conformal field theory with
boundary, defining the free string theory. Interactions involving the interior
of open and closed strings are governed by a twist operator in the bulk, while
string end-points are created and destroyed by a boundary twist operator.Comment: 20 pages,in harvmac.tex `b' mode; epsf.tex for 12 figure