  The electronic and optical conductivities for anisotropic tilted Dirac
semimetals are calculated using the Kubo formula. As in graphene, it is shown
that the minimal conductivity is sensitive to the order in which the
temperature, frequency and scattering limits are taken. Both intraband and
interband scattering are found to be direction dependent. In the high frequency
and low temperature limit, the conductivities do not depend on frequency and
are weighted by the anisotropy in such a way that the geometrical mean
$\sqrt{\sigma_{xx}\sigma_{yy}}$ of the conductivity is the same as in graphene.
This results from the fact that in the zero temperature limit, interband
transitions are not affected by the tilt in the dispersion, a result that is
physically interpreted as a global tilting of the allowed transitions. Such
result is verified by an independent and direct calculation of the absorption
coefficient using the Fermi golden rule. However, as temperature is raised, an
interesting minimum is observed in the interband scattering, interpreted here
as a result of the interplay between the tilt and the chemical potential
increasing with temperature.
