Growth rates of unbounded orbits in nonperiodic twist maps and a theorem by Neishtadt
Growth rates of unbounded orbits in nonperiodic twist maps and a theorem by Neishtadt

Markus Kunze , Mathematisches Institut der Universit¨at K¨oln
Rutgers  Hill Center, Room 705
We consider twist maps on the plane (like the pingpong map) with nonperiodic angles, where typically bounded and unbounded motions coexist. For the latter case we prove a theorem which shows that in the analytic setting the growth rate is at most logarithmic, and furthermore an example of a system is given where all orbits grow at this rate. Moreover, we determine the optimal growth rate for a pingpong with finite regularity. (This is joint work with R. Ortega.)