Аннотация:
We examine the role of long–range interactions on the dynamical and statistical properties of two
1D lattices with on–site potentials that are known to support discrete breathers: the Klein–Gordon
(KG) lattice which includes linear dispersion and the Gorbach–Flach (GF) lattice, which shares the
same on–site potential but its dispersion is purely nonlinear. In both models under the implementation
of long–range interactions (LRI) we find that single–site excitations lead to special low–dimensional
solutions, which are well described by the undamped Duffing oscillator. For random initial conditions
we observe that the maximal Lyapunov exponent scales as N−0.12 in the KG model and as N−0.27 in
the GF with LRI, suggesting in that case an approach to integrable behavior towards the thermodynamic
limit. Furthermore, under LRI, their non-Gaussian momentum distributions are distinctly different from
those of the FPU model.