  Using perturbative QED we show that, while the retarded dispersive force
between an electrically polarizable atom and a magnetically polarizable one is
proportional to $1/r^{8}$, where $r$ is the distance between the atoms, the
non-retarded force is proportiaonal to $1/r^{5}$. This is a rather surprising
result that should be compared with the dispersive van der Waals force between
two electrically polarizable atoms, where the retarded force is also
proportional to $1/r^{8}$, but the non-retarded force is proportional to
$1/r^{7}$.
