The soft S $$ mathcal{S} $$ -matrix in gravity
Abstract The gravitational S $$ mathcal{S} $$ -matrix defined with an infrared (IR) cutoff factorizes into hard and soft factors.The soft factor is universal and contains all the IR and collinear divergences.Here we show, in a momentum space basis, that the intricate expression for the soft factor is fully reproduced by two boundary currents, which