Zuriguel, I. (Iker); Boudet, J.F. (Jean-Français); Amarouchen, Y. (Yacine). "Role of fluctuation-induced interactions in the axial segregation of granular materials". Physical review letters. 2005; 95 (25), 258002
The movement of a few large diameter spheres immersed in a granular medium composed of smaller beads in a rotating cylinder is studied. We evidence attractions and repulsions between the large spheres depending on the rotation frequency. The large spheres also show relative position fluctuations which are Gaussian. A complete study of this problem sheds new light on the problem of size segregation in granular materials and points to the importance of fluctuation-induced interactions.