On (Scalar QED) Gravitational Positivity Bounds

Abstract

We study positivity bounds in the presence of gravity. We first review the gravitational positivity bound at the tree-level, where it is known that a certain amount of negativity is allowed for the coefficients of higher-derivative operators. The size of these potentially negative contributions is estimated for several tree-level, Reggeized gravitational amplitudes which are unitary at high energies and feature the t-channel pole characteristic of graviton exchange. We also argue for the form of the one-loop Regge amplitude assuming that the branch cut structure associated with the exchange of the graviton and higher-spin particles is reflected. We demonstrate how the one-loop Regge amplitude appears by summing over Feynman diagrams. For our one-loop amplitude proposal, the positivity bounds generically receive a finite contribution from the Regge tower and do not lead to a parametrically small bound on the cut-off scale of the low-energy EFT, consistent with recent studies based on sum rules of the amplitude.

27 pages, 5 figures, matches version published in JHEP

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Cited by in corpus (5)

• Running Love Numbers and the Effective Field Theory of Gravity
• Black Hole Extremality in Nonlinear Electrodynamics: A Lesson for Weak Gravity and Festina Lente Bounds
• Positivity Bounds in Scalar Effective Field Theories at One-loop Level
• Gravitational Positivity for Phenomenologists: Dark Gauge Boson in the Swampland
• Positivity bounds in scalar-QED EFT at one-loop level