  We compare a fully quantum mechanical numerical calculation of the
conductivity of graphene to the semiclassical Boltzmann theory. Considering a
disorder potential that is smooth on the scale of the lattice spacing, we find
quantitative agreement between the two approaches away from the Dirac point. At
the Dirac point the two theories are incompatible at weak disorder, although
they may be compatible for strong disorder. Our numerical calculations provide
a quantitative description of the full crossover between the quantum and
semiclassical graphene transport regimes.
