Spontaneous Ratchet Effect in a Granular Gas
arXiv:cond-mat/0306640 · doi:10.1103/PhysRevLett.92.184301
Abstract
The spontaneous clustering of a vibrofluidized granular gas is employed to generate directed transport in two different compartmentalized systems: a "granular fountain" in which the transport takes the form of convection rolls, and a "granular ratchet" with a spontaneous particle current perpendicular to the direction of energy input. In both instances, transport is not due to any system-intrinsic anisotropy, but arises as a spontaneous collective symmetry breaking effect of many interacting granular particles. The experimental and numerical results are quantitatively accounted for within a flux model.
4 pages, 5 figures; Fig. 4 has been reduced in size and quality