Finite-time memory detectors and fully constraining Faddeev-Kulish dressings in QED and gravity

Abstract: We show that for both QED and perturbative quantum gravity, finite-time Faddeev-Kulish dressings can be fully constrained by symmetry, and that this gives the unique choice which reproduces the classical memory effect. For gravity, we show that using this dressing to construct finite-time Fock spaces, as well as a carefully defined finite-time memory detector allows us to recover both the first order gravitational memory, as well as higher order Christodoulou contributions from the gravitational field. We explain how these higher order perturbative corrections arise in inclusive in-in calculations.