  The mechanical action of light on atoms is nowadays a tool used ubiquitously
in cold atom physics. In the semiclassical regime where the atomic motion is
treated classically, the computation of the mean force acting on a two-level
atom requires in the most general case numerical approaches. Here we show that
this problem can be tackled in a pure analytical way. We provide an analytical
yet simple expression of the mean force that holds in the most general case
where the atom is simultaneously exposed to an arbitrary number of lasers with
arbitrary intensities, wave vectors, and phases. This yields a novel tool for
engineering the mechanical action of light on single atoms.
