1996/06/30 by Joseph Polchinski · 1 citation
Mathematics · Physics and Astronomy · #Algebraic structures and combinatorial models #Algorithm #Black Holes and Theoretical Physics #Consistency (knowledge bases) #Geology #Geometry #Gravitational singularity #Homotopy and Cohomology in Algebraic Topology #Mathematical analysis #Mathematical physics #Mathematics #Orbifold #Orientifold #Pure mathematics #Supersymmetry #Type (biology) #hep-th
paper · pdf · doi:10.1103/physrevd.55.6423
published as Phys.Rev.D55:6423-6428,1997 · References added. 16 pages, LaTeX
arxiv created 1996/07/06 · openalex publication_date 1997/05/15 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Recently Gimon and Johnson and Dabholkar and Park have constructed type I theories on K3 orbifolds. The spectra differ from that of type I on a smooth K3, having extra tensors. We show that the orbifold theories cannot be blown up to smooth K3's, but rather Z2 orbifold singularities always remain. Douglas's recent proposal to use D-branes as probes is useful in understanding the geometry. The Z2 singularities are of a new type, with a different orientifold projection from those previously considered. We also find a new world-sheet consistency condition that must be satisfied by orientifold models.