Gravitational Regge bounds

Understand

We review the basic assumptions and spell out the detailed arguments that lead to the bound on the Regge growth of gravitational scattering amplitudes.

• The minimal extra ingredient compared to the gapped case - in addition to unitarity, analyticity, subexponentiality, and crossing - is the assumption that scattering at large impact parameters is controlled by known semi-classical physics.
• We bound the Regge growth of amplitudes both with the fixed transferred momentum and smeared over it.
• Our basic conclusion is that gravitational scattering amplitudes admit dispersion relations with two subtractions.