Energy relaxation in Fermi–Pasta–Ulam arrays

The dynamics of energy relaxation in thermalized one- and two-dimensional arrays with nonlinear interactions depend in detail on the interactions and, in some cases, on dimensionality. We describe and explain these differences for arrays of the Fermi–Pasta–Ulam type. In particular, we focus on the roles of harmonic contributions to the interactions and of breathers in the relaxation process.