Theory HEP Seminar

de Sitter vacua in string theory: from the landscape to the swampland

Mariana Grana

CEA/Saclay

Despite its uniqueness, string theory has a “landscape” of low-energy solutions with very different observable physics. These solutions are usually found using low-energy effective theories which, in order to satisfy experimental constraints such as the accelerated expansion of the universe, require a number of exotic ingredients whose string theory origin is unclear. The so-called “de Sitter swampland conjecture” speculates that de Sitter space is in the “swampland”, i.e. in the set of seemingly consistent low energy effective theories that cannot be consistently coupled to quantum gravity. In this talk we will review de Sitter solutions in string theory, and try to situate them somewhere on the scenery of string theory.