Speaker
Waltraut Knop
Description
In this talk, we continue the tree-level S-matrix bootstrap program for quantum gravity in ten-dimensional theories with half-maximal supersymmetry. Imposing analyticity, crossing symmetry, unitarity, and Regge boundedness, we constrain weakly coupled UV completions of supergravity and derive bounds on effective field theory coefficients. We show how the heterotic and closed string theories arise as consistent UV completions within the allowed region. Under mild spectral assumptions, much of the boundary is explained by extremal amplitudes supported on a single linear Regge trajectory, providing further evidence that linear Regge trajectories are a robust feature of the tree-level quantum-gravity bootstrap.