Numerical studies on boundary effects on the FPU paradox

We study numerically the dynamics of a chain of particles subjected to an on site restoring nonlinear force and a first neighbor harmonic coupling. We excite the first linear mode and investigate the distribution of the average harmonic energies at metastable regime, in the spirit of Fermi Pasta Ulam experiment. The limit distribution turns out to strongly depend on the boundary conditions. A theoretical discussion of the phenomenon is also given.