My research interests begin with string phenomenology—broadly speaking the effort to extract testable predictions from string theory or any other consistent theory of quantum gravity—and range into formal quantum field theory, quantum gravity, and cosmology. In the past, I have worked on the hierarchy problem and collider phenomenology, and I retain an interest in these areas as well.

Recently, I have worked extensively on the Weak Gravity Conjecture, a class of hypotheses about the spectrum of charged particles in quantum gravities with interesting implications for phenomenology.

Another focus of my recent research is electromagnetic duality in gauge theories with minimal supersymmetry, related to D-brane physics in string theory.

I am also interested in exotic quantum field theories and quantum gravities, breaking some of the “rules” that we expect ordinary physics to obey. While such theories are not designed to model our universe, they may provide further insight into theoretical physics as a whole, with consequences for more realistic theories.