



01252nas a2200157   4500008004100000245003400041210002700075260000900102490000800111520082700119100001900946700002300965700002300988700002101011856006201032       2018                        eng d00aOn the need for soft dressing0 aneed for soft dressing  c20180 v1213 a<p>In order to deal with IR divergences arising in QED or perturbative quantum gravity scattering processes, one can either calculate inclusive quantities or use dressed asymptotic states. We consider incoming superpositions of momentum eigenstates and show that in calculations of cross-sections these two approaches yield different answers: in the inclusive formalism no interference occurs for incoming finite superpositions and wavepackets do not scatter at all, while the dressed formalism yields the expected interference terms. This suggests that rather than Fock space states, one should use Faddeev-Kulish-type dressed states to correctly describe physical processes involving incoming superpositions. We interpret this in terms of selection rules due to large U(1) gauge symmetries and BMS supertranslations.</p>1 aCarney, Daniel1 aChaurette, Laurent1 aNeuenfeld, Dominik1 aSemenoff, Gordon  uhttps://www.quics.umd.edu/publications/need-soft-dressing