Astrid de Wijn: Vertical chaos and horizontal diffusion in the bouncing-ball billiard
Abstract:
The bouncing-ball billiard is an interesting, low-dimensional system in which transport properties of real physical systems can be studied theoretically. We study the bouncing-ball billiard, which was first introduced in ref. [3], with non-convex scatterers with small slopes. We show that there is a time-scale separation between the horizontal and vertical motion, which is controlled by the slope of the billiard. We apply the theory of time-scale separation developed in ref. [2]. If the vertical motion is chaotic, the horizontal motion is diffusive, but if the vertical motion is (quasi-)periodic, there is no diffusion. We confirm the results with numerical simulations. Hence, the order-chaos transition in the vertical degrees of freedom translates into a localisation-delocalisation transition for the horizontal motion.

[1] Astrid S. de Wijn and Holger Kantz, Physical Review E 75 046214 (2007).
[2] Anja Riegert, Niluefer Baba, Katrin Gelfert, Wolfram Just, Holger Kantz, Phys. Rev. Lett. 94 054103 (2005).
[3] Laszlo Mátyás and Rainer Klages, Physica D 187 165 (2004).