Weak Gravity Conjecture and positivity conditions

by Dr. Stefano Andriolo

Ben-Gurion University
at Particles and Fields Seminar

Mon, 01 Mar 2021, 14:00


In this talk, we study the relationship between the Weak Gravity Conjecture (WGC) and positivity conditions imposed by causality, analyticity and unitarity of scattering amplitudes. In the first part, we take a 3D/4D effective field theory with massive particles charged under multiple U(1) gauge fields. After integrating out the particles, we can derive constraints on the charge-to-mass ratios of such particles from requiring that photons propagate causally and have an analytic S-matrix. We thus find that the theories need to contain bi-fundamentals and satisfy the WGC. Moreover, demanding self-consistency of the constraints under Kaluza-Klein compactification, we show that (for scalars) they imply a stronger version of the weak gravity conjecture, in which the charge-to-mass ratios of an infinite tower of particles are bounded from below. In the second part, we present an example where the derivation of the WGC requires more detailed UV information than the consistency of scattering amplitudes. We do so by taking an axion-dilaton-gravity system, and show that the (axionic) WGC can be satisfied if we assume duality constraints on higher derivative corrections on top of to positivity bounds, while it does not follow if we assume positivity bounds only.

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Created on 26-02-2021 by Palti, Eran (palti)
Updaded on 26-02-2021 by Palti, Eran (palti)