Gravity is the weakest force: S-matrix arguments and implications

by Anna Tokareva

Tuesday Feb 17, 2026, 12:00 PM → 1:30 PM Europe/Madrid

IFAE Downstairs Meeting Room 28 (In-Person)

I propose a derivation of the lower bound on the absolute value of the shift-symmetric scalar self-coupling in the presence of gravity. I implement unitarity and causality of both low energy theory and its UV completion in dispersion relation techniques. A set of non-linear integral inequalities can be constructed in such a way, that the infrared divergences cancel each other providing with a non-trivial constraint which predicts that a theory coupled to gravity must gain self-interactions. I discuss further generalizations and implications of consistency constraints on gravitational EFTs for black hole physics and early Universe cosmology.