  The electric drift current bias was recently introduced as a new paradigm to
break the Lorentz reciprocity in graphene. Here, we study the impact of the
nonreciprocal response in the energy extracted from a beam of swift charges
travelling in the vicinity a graphene sheet with drifting electrons. It is
demonstrated that the drift bias leads to an asymmetric electron-energy-loss
spectrum that depends on the sign of the charges velocity. It is found that
when the drift and electron beam velocities have comparable values but opposite
signs, the energy loss is boosted resulting in a noncontact friction-type
effect. In contrast, when the drift and electron beam velocities have the same
sign the energy loss is negligible. Furthermore, it is shown that different
theoretical models of the drift-biased graphene conductivity yield distinct
peaks for the energy-loss spectrum, and thereby electron beam spectroscopy can
be used to test the validity of the different theories.
