Twisted open strings from closed strings: the WZW orientation orbifolds

摘要

Including world-sheet orientation-reversing automorphisms (h) over cap (sigma) is an element of H_ in the orbifold program, we construct the operator algebras and twisted KZ systems of the general WZW orientation orbifold A(g)(H_)/H_. We find that the orientation-orbifold sectors corresponding to each (h) over cap (sigma) is an element of H_ are twisted open WZW strings, whose properties are quite distinct from conventional open-string orientifold sectors. As simple illustrations, we also discuss the classical (high-level) limit of our construction and free-boson examples on Abelian g.