Starts 16 Sep 2026 16:00
Ends 16 Sep 2026 17:00
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HECAP Seminar by Michelangelo Tartaglia - Asymmetric Orbifolds with Vanishing One-Loop Vacuum Energy
Hybrid
Leonardo Building - Lagrange Lecture Hall and via Zoom
!!! Please note unusual day !!!
Abstract
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.
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.