Beschreibung
T-duality for non-critical heterotic strings
Non-critical heterotic strings with linear dilaton backgrounds are formally related to their critical non-supersymmetric counterparts. I will show that their T-duality symmetry groups upon circle compactification are of the form O(1,12+D/2,Z) for even dimension D. I will explain how the global structure of each moduli space is encoded in an extended Dynkin diagram, generalizing known results for critical supersymmetric and non-supersymmetric strings. In the context of subcritical strings, these moduli spaces represent deformations of heterotic brane backgrounds. These results suggest that the heterotic NS5 brane is related through T-duality to recently constructed non-supersymmetric heterotic branes. These backgrounds can also be obtained through the Hellerman-Swanson tachyon condensation process, suggesting that a pair of winding tachyons in a Scherk-Schwarz circle at self-dual radius can condense into a pair of coincident NS5-branes for a generic heterotic string.
