Motion of islands on vibrating smectic films

Vibrating SmA- and SmC-like films act as a kind of mechanical trap for small inclusions such as islands (thicker regions of the film), which tend to converge towards points of maximal amplitude. This behavior is due to lateral non-linear inertia forces. Small islands turned out to be a good probe to study this non-linear force field, In this paper, eve study the trajectories of islands in the field of the lateral NL force. We detect these non-linear forces and compare them with the gravitational force.