Radiation problems accompanying carrier production by an electric field in the graphene

TL;DR

This paper investigates radiation phenomena in graphene subjected to strong electric fields, combining nonperturbative Dirac model analysis with kinetic equations to predict observable effects like spectral anisotropy and harmonic generation.

Contribution

It develops a comprehensive kinetic formalism for photon radiation from electron-hole plasma in graphene under strong fields, including analytical and numerical results.

Findings

Predicted spectral anisotropy of quantum radiation

Possible presence of even harmonics in emitted radiation

Development of an advanced kinetic equation framework

Abstract

A number of physical processes occurring in a flat one-dimensional graphene structure under the action of strong time-dependent electric fields are considered. It is assumed that the Dirac model can be applied to the graphene as a subsystem of the general system under consideration, which includes an interaction with quantized electromagnetic field. The Dirac model itself in the external electromagnetic field (in particular, the behavior of charged carriers) is treated nonperturbatively with respect to this field within the framework of strong-field QED with unstable vacuum. This treatment is combined with a kinetic description of the radiation of photons from the electron-hole plasma created from the vacuum under the action of the electric field. An interaction with quantized electromagnetic field is described perturbatively. A significant development of the kinetic equation formalism is presented. A number of specific results are derived in course of analytical and numerical study of the equations. We believe that some of predicted effects and properties of considered processes may be verified experimentally. Among these effects, it should be noted a characteristic spectral composition anisotropy of the quantum radiation and a possible presence of even harmonics of the external field in the latter radiation.