(15.10.) Asymmetric orbifolds with vanishing one-loop vacuum energy
Michelangelo Tartaglia (IFT Madrid )
15.10.2026 at 16:15
I will talk about a series of works on the classification of 4D non-supersymmetric asymmetric Type II orbifold which nonetheless have vanishing cosmological constant to at least some orders in string perturbation theory. These are engineered by the conservation of a supercharge-like operator in each individual sector in the orbifold sum, despite the overall explicit breaking of spacetime SUSY. By turning this condition into a precise representation theory problem, we can fully classify the allowed point groups, both Abelian and non-Abelian. Along the way, we computed bordism groups $\Omega_3^{\text{Spin}}(BG)$ for a variety of crystallographic groups G to ensure the absence of global anomalies.
A348