described in the context of ordinary quantum field theory. In fact, one can
find explicit solutions of the semi-classical Einstein equation that correspond
to black holes. In this picture, the black hole is just a long-lived resonance
and its evaporation is just a decay of the resonance, so the time evolution is
unitary and no information is lost.
Causality and unitarity as old principles, together with modern techniques, can put strong constraints on EFT. We think of modifications of Einstein gravity as low-energy gravity EFT, we will demonstrate how causality and unitarity can constrain the modifications by using dispersive sum rules of 2->2 amplitudes. Our bounds imply that gravitational interactions must shut off uniformly in the G->0 limit, and prove the scaling with higher-spin mass. We will also discuss possible experimental implications in the future.