Exclusion of de Sitter Vacua and Naturalness

ABSTRACT
According to the landscape view, the origin of physical parameters, such as the vacuum energy or the Higgs mass, is linked with the existence of a vast landscape of de Sitter vacua, supposedly provided by quantum gravity. The assumed plentitude of such vacua is a necessary ingredient for anthropic selection. In this talk we shall provide evidence that the situation is actually the opposite and that the de Sitter landscape is incompatible with quantum gravity. In this way, quantum gravity/string theory nullifies an outstanding cosmological puzzle of vacuum energy. The exclusion of an eternally inflating Universe raises a number of fundamental questions about past and future cosmology. It also leads to new predictions about cosmological observables and about the nature of dark energy. The lack of anthropic and cosmological selections sharpens other naturalness questions, such as the weak scale hierarchy and strong-CP violation, and correspondingly strengthens the case for new physics.
BIO
Gia Dvali is a professor and chair at Ludwig Maximilians University and a director of Max Planck Institute for Physics in Munich. His research is focused on the physics beyond the Standard Model. His main goal is to understand the fundamental laws of Nature and to link them with experimental signatures in high-energy particle accelerators, cosmology and astrophysics. He also has a very strong interest in many-body quantum systems and quantum information, and has established a link between these two subject areas through black holes and cosmology. His papers on large extra dimensions, together with Nima Arkani-Hamed and Savas Dimopoulos, are some of his most influential works and opened new paths to understand gravity and its weakness compared to other forces.

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