Tail resonances of Fermi-Pasta-Ulam q-breathers and their impact on the pathway to equipartition.

  title={Tail resonances of Fermi-Pasta-Ulam q-breathers and their impact on the pathway to equipartition.},
  author={Tiziano Penati and Sergej Flach},
  volume={17 2},
Upon initial excitation of a few normal modes the energy distribution among all modes of a nonlinear atomic chain (the Fermi-Pasta-Ulam model) exhibits exponential localization on large time scales. At the same time, resonant anomalies (peaks) are observed in its weakly excited tail for long times preceding equipartition. We observe a similar resonant tail structure also for exact time-periodic Lyapunov orbits, coined q-breathers due to their exponential localization in modal space. We give a… 

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