Lévy flights and Hydrodynamic Superdiffusion on the Dirac Cone of Graphene

It is shown that hydrodynamic collision processes in graphene at the neutrality point can be described in terms of a Fokker-Planck equation with a fractional derivative. This is a consequence of the fact that the phase space dynamics of electrons is governed by Lévy flights: rare large-angle scattering events interrupting the small-angle scattering. Lévy flights give rise to superdiffusive dynamics of collective excitations. Implications for transport and relaxation processes will be discussed.