Subleading soft dressings of asymptotic states in QED and perturbative quantum gravity

The infrared structure of perturbative gauge theories

“…• It is clear from the procedure leading to Eq. (1.60) that there is ample freedom in choosing what to include in the 'asymptotic' behaviour of the Hamiltonian, and therefore in the coherent state operator: depending on the application one has in mind, one might want to include in the asymptotic dynamics also terms that do not lead to divergences in the amplitudes, or sub-leading powers in the resolution parameter [169,170]. This could provide an interesting avenue to explore infrared enhancements, and eventually resummations, beyond leading power, a subject that has recently received considerable attention, and could lead to relevant phenomenological applications (see, for example, [137] and references therein).…”