A RENORMALIZATION-GROUP FOR HAMILTONIANS - NUMERICAL RESULTS

We describe a renormalization group transformation that is related to the break-up of golden invariant tori in Hamiltonian systems with two degrees of freedom. This transformation applies to a large class of Ha miltonians, is conceptually simple, and allows for accurate numerical computations. In a numerical implementation, we find a non-trivial fix ed point and determine the corresponding critical index and scaling. O ur computed values for various universal constants are in good agreeme nt with existing data for area-preserving maps. We also discuss the fl ow associated with the non-trivial fixed point.