Stability of non-supersymmetric string theory backgrounds – NON-SUSY-STRINGS

Over the last decade, experiments have all but ruled out low-energy supersymmetry. It has thus become imperative to understand supersymmetry breaking in our best-developed theory of quantum gravity, string theory. However, constructing stable, and thus physically viable, non-supersymmetric solutions of string theory is such an open and difficult problem that even their existence has recently been thrown into doubt.

In NON-SUSY-STRINGS, I will address the following existential question for string theory: Does string theory admit stable non-supersymmetric solutions?

My study differs in a crucial way from previous work, which largely ignored the difficulty of 10-dimensional string theory by using simplified lower-dimensional models. However, these models typically fail to capture all the relevant physics. In NON-SUSY-STRINGS, I will instead determine stability directly in 10 dimensions by using the powerful new geometric formalism of Exceptional Field Theory (ExFT). In a recent breakthrough, I have set the stage for this research, by developing a method to determine the 10-dimensional perturbative stability of a large class of non-supersymmetric vacua of string theory.

In NON-SUSY-STRINGS, I will construct new non-supersymmetric vacua and develop novel methods to address two other crucial challenges for their stability: non-perturbative decays and the effects of string corrections. Finally, I will calculate important physical signatures of non-supersymmetric vacua of string theory and establish their phenomenology.

The results of NON-SUSY-STRINGS will determine whether string theory can model our non-supersymmetric universe. In addition, NON-SUSY-STRINGS develops crucial new tools for the study of string theory, with a variety of applications in string phenomenology and the AdS/CFT correspondence.