The effect of changing the multiplicity of terms in the Cauchy problem for the Dirac equation in graphene with a constant electric field and a localized initial condition.

This paper considers the Cauchy problem for a two-dimensional massless Dirac equation in graphene with a constant electric field. It is assumed that, initially, the localized wave function describes quasi-electrons with momenta lying in the right half-plane. The article describes an effect based on the phenomenon of changing the multiplicity of terms (characteristics), leading to Klein tunneling. After some time, a hole component appears in addition to the wave function for the electron component. They move in opposite directions, with the hole component localized in the vicinity of the moving point.