Annular billiard dynamics in a circularly polarized strong laser field
  We analyze the dynamics of a valence electron of the buckminsterfullerene molecule (C60) subjected to a circularly polarized laser field by modeling it with the motion of a classical particle in an annular billiard. We show that the phase space of the billiard model gives rise to three distinct trajectories: "Whispering gallery orbits", which only hit the outer billiard wall, "daisy orbits" which hit both billiard walls (while rotating solely clockwise or counterclockwise for all time), and orbits which only visit the downfield part of the billiard, as measured relative to the laser term. These trajectories, in general, maintain their distinct features, even as intensity is increased from 10^10 to 10^14 W*cm^-2. We attribute this robust separation of phase space to the existence of twistless tori. 
Adam Kamor, Francois Mauger (CPT), Cristel Chandre (CPT), Turgay Uzer
physics.atom-ph