title: Application of the Bogoliubov-Krylov method of averaging to the Fermi-Pasta-Ulam system.
abstract: We apply the Bogoliubov-Krilov method of averaging to the study of the stability of the pi -mode solution (N/2 one-mode nonlinear solution) of the Fermi-Pasta-Ulam- beta system, with negative values of the nonlinearity parameter beta in the Hamiltonian of the system. The analysis is made as a function of the number N of the particles and of the product lambda = epsilon|beta|, where epsilon is the energy density. The results of this application are in excellent agreement with those obtained by the direct integration of motion equation.
authors.affiliation: Dipartimento di Fisica dell'Università, 73100 Lecce, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Leo
authors.forename: R A
authors.initials: RA
authors.lastname: Leo