  A small polarizable object (an atom, molecule or nanoparticle), placed above
a medium with flowing dc current in it, is considered. It is shown that the dc
current can have a strong effect on the force exerted on the particle. The
Casimir-Lifshitz force, well studied in the absence of current, gets modified
due to drifting mobile carriers in the medium. Furthermore, a force in the
lateral direction appears. This force is a non-monotonic function of the drift
velocity and its maximal value is comparable with the Casimir-Lifshitz force.
If the temperatures of the medium and the particle are different, this lateral
force can be directed along the current (drag) or in the opposite direction
(anti-drag).
