Dispersion relations are statements of causality. They give sum rules connecting infrared and ultraviolet physics. While they originate in optics and quantum field theory, I will argue that their 'true purpose' is gravity, viewed as a low-energy effective theory. This is due to the unique energy dependence of this force. I will present ongoing work mapping out the space of consistent effective theories, including recent results deriving in scalar models quantitative version of dimensional analysis scaling from causality.
https://desy.zoom.us/j/95793371145 (Password: 246065)