IAS Fundamental Physics Seminar Series - 4D de Sitter from 6D Gauged Supergravity with Green-Schwarz Counterterm

Abstract
The ΛCDM model provides the standard description of our Universe, yet the origin of the cosmological constant remains unresolved. The speaker will show that in a class of anomaly-free six-dimensional supergravity theories with local R-symmetry, one can naturally obtain classical four- and six-dimensional vacuum solutions with a positive cosmological constant. This mechanism does not rely on nonperturbative effects or higher-order corrections, which are typically required in conventional string-theoretic constructions, and thus provides a new realization of de Sitter vacua within the low-energy effective theory of quantum gravity.