“…Is it possible to get rid of the "anti-velocity" altogether? In the present Letter we show that this is feasible by using a method which has been introduced by Barbashov and coworkers [2,3,4] nearly 40 years ago. They showed how one can amputate exact Green functions in Quantum Field Theory without using perturbation theory but their work doesn't seem to have received much attention apart from the (rather specialized) field of quantum gravity where Fabbrichesi, Han and others [5,6,7,8] have extensively used the Barbashov method to describe gravitational scattering.…”