High Energy Theory Seminar: Vincent Van Hemelryck

Title: Supersymmetric scale-separated AdS3 orientifold vacua of type IIB

Abstract: A central and ongoing question in string theory is whether flux compactifications can achieve scale separation, meaning that the cosmological constant is significantly smaller than the KK cut-off scale. In this talk, I will review the state of the art of this problem, with a particular emphasis on compactifications involving non-vanishing internal curvature. Scale separation occurs in these scenarios when the internal scalar curvature decouples from the lowest non-trivial eigenvalue of the Laplacian, with two-step nilmanifolds serving as concrete examples. I will illustrate this with new 3d supersymmetric and scale-separated orientifold vacua of type IIB string theory, arising from compactifications on nilmanifolds with co-closed G2-structure.