Kinetics of ehγ excitations generated in graphene by time-dependent electric fields

The kinetics of ehγ excitations in graphene generated by time-dependent electric fields is studied. To do this, following the work [1] and using methods of kinetic theory in QED with strong electromagnetic fields [2], we construct a consistent system of kinetic equations (KE), which nonperturbatively describes the generation and evolution of eh subsystem under the influence of an external electric field and takes into account interaction between eh and photon subsystems in the second order of the perturbation theory. The constructed KE system takes into account all single-photon processes: the stimulated photoproduction and annihilation of eh pairs and carrier redistribution over momenta. The corresponding single-photon channels open in the presence of an external time-dependent electric field, which is consistent with the general theory of the influence of external fields on elementary processes of interaction in multiparticle systems [3,4]. Maxwell's equations for the internal plasma field complement the system of KE. In the framework of this approach, electromagnetic radiation from graphene, which accompanies ehγ excitation, is considered. The latter results are compared with the radiation of plasma oscillations in graphene studied earlier in [5].