  We study the interplay between antiferromagnetism and superconductivity in a
generalized infinite-$U$ Anderson lattice, where both superconductivity and
antiferromagnetic order are introduced phenomenologically in mean field theory.
In a certain regime, a quantum phase transition is found which is characterized
by an abrupt expulsion of magnetic order by d-wave superconductivity, as
externally applied pressure increases. This transition takes place when the
d-wave superconducting critical temperature, $T_c$, intercepts the magnetic
critical temperature, $T_m$, under increasing pressure. Calculations of the
quasiparticle bands and density of states in the ordered phases are presented.
We calculate the optical conductivity $\sigma(\omega)$ in the clean limit. It
is shown that when the temperature drops below $T_m$ a double peak structure
develops in $\sigma(\omega)$.
