title: Nonlinear parametric instability in double-well lattices.
abstract: A possibility of a nonlinear resonant instability of uniform oscillations in dynamical lattices with harmonic intersite coupling and onsite nonlinearity is predicted. Numerical simulations of a lattice with a double-well onsite anharmonic potential confirm the existence of the nonlinear instability with an anomalous value of the corresponding power index, approximately 1.57, which is intermediate between the values 1 and 2 characterizing the linear and nonlinear (quadratic) instabilities. The anomalous power index may be a result of a competition between the resonant quadratic instability and nonresonant linear instabilities. The observed instability triggers transition of the lattice into a chaotic dynamical state.
authors.affiliation: Department of Theoretical Physics, Palacký University, Tr. 17, Listopadu 50, 77207 Olomouc, Czech Republic.
authors.forename: J
authors.initials: J
authors.lastname: Riedel
authors.forename: B A
authors.initials: BA
authors.lastname: Malomed
authors.forename: E
authors.initials: E
authors.lastname: Majerníková