Title: The Fermi-Pasta-Ulam Model: Periodic Solutions
Authors: G. Arioli, H. Koch, S. Terracini
Abstract:   We introduce two novel methods for studying periodic solutions of the FPU beta-model, both numerically and rigorously. One is a variational approach, based on the dual formulation of the problem, and the other involves computer-assisted proofs. These methods are used e.g. to construct a new type of solutions, whose energy is spread among several modes, associated with closely spaced resonances.
Paper: Preprint, programs and data files, formatted program source