Non-supersymmetric heterotic strings on tori

In the absence of experimental evidence for supersymmetry, compactifications of the non-supersymmetric heterotic strings make their reappearance in the landscape of possibly phenomenologically-relevant backgrounds. Furthermore, they have been recently used to build non-supersymmetric AdS backgrounds, which according to one of the swampland conjectures, should not be part of the landscape. In this talk we will analyse compactifications on string-size tori, focusing on the phenomenon of gauge symmetry enhancement at special points in moduli space.Concentrating on the circle, we find all the points that have non-Abelian gauge symmetries of maximal rank, and analyze their matter spectrum. We show that all gauge symmetry enhancements, and where they are realised in moduli space, can actually be obtained from an extended Dynkin diagram. We will show the one-loop cosmological constant, as well as its Hessian at points of maximal enhancement, finding a surprising result. Finally, we will discuss their use in building non supersymmetric AdS backgrounds.

27th February 2024, 14:30