Moving discrete breathers in a β-FPU lattice revisited

摘要

In this work we revisit the existence, stability and dynamical properties of moving discrete breathers in beta-FPU lattices. On the existence side, we propose a numerical procedure, based on a continuation along a sequence of velocities, that allows us to systematically construct breathers traveling more than one lattice site per period. On the stability side, we explore the stability spectrum of the obtained waveforms via Floquet analysis and connect it to the energy-frequency bifurcation diagrams. We illustrate in this context examples of the energy being a multivalued function of the frequency, showcasing the coexistence of different moving breathers at the same frequency. Finally, we probe the moving breather dynamics and observe how the associated instabilities change their speed, typically slowing them down over long-time simulations. (c) 2022 Elsevier B.V. All rights reserved.