title: Energy localization in the phi4 oscillator chain.
abstract: We study energy localization in a finite one-dimensional phi(4) oscillator chain with initial energy in a single oscillator of the chain. We numerically calculate the effective number of degrees of freedom sharing the energy on the lattice as a function of time. We find that for energies smaller than a critical value, energy equipartition among the oscillators is reached in a relatively short time. On the other hand, above the critical energy, a decreasing number of particles sharing the energy is observed. We give an estimate of the effective number of degrees of freedom as a function of the energy. Our results suggest that localization is due to the appearance, above threshold, of a breather-like structure. Analytic arguments are given, based on the averaging theory and the analysis of a discrete nonlinear Schrödinger equation approximating the dynamics, to support and explain the numerical results.
authors.affiliation: Dipartimento di Matematica F. Enriques, Università degli Studi di Milano, Italy. ponno@math.unipd.it
authors.forename: A
authors.initials: A
authors.lastname: Ponno
authors.forename: J
authors.initials: J
authors.lastname: Ruggiero
authors.forename: E
authors.initials: E
authors.lastname: Drigo
authors.forename: J
authors.initials: J
authors.lastname: De Luca