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Research Van Swinderen Institute

Lunch seminar David Marsh

When:Tu 08-03-2016 12:30 - 13:30


David Marsh


University of Cambridge, UK


Genericity and universality in the string theory landscape


In random supergravities with many fields, an exceedingly small fraction of typical de Sitter critical points are metastable vacua. In this talk, I will show that while string compactifications of type IIB string theory and F-theory give rise to a large set of four-dimensional effective theories, these are  not random in the sense of random supergravities. Geometric relations inherited from the Calabi-Yau compactification manifold may crucially affect the properties of the low-energy theory. I will show that in some regions of the moduli space, general IIB/F-theory flux compactifications exhibit analytically computable universal properties that are independent of the compactification geometry, number of moduli, or the detailed flux choice. The corresponding spectra are in stark contrast with the expectations from random supergravity. Finally, I will discuss how de Sitter vacua appear with comparatively little tuning by spontaneous supersymmetry breaking in compactifications with a weakly broken “no-scale” symmetry.