Discrete breathers in dissipative lattices - art. no. 066603

We study the properties of discrete breathers, also known as intrinsic loca lized modes, in the one-dimensional Frenkel-Kontorova lattice of oscillator s subject to damping and external force. The system is studied in the whole range of values of the coupling parameter, from C=0 (uncoupled limit) up t o values close to the continuum limit (forced and damped sine-Gordon model) . As this parameter is varied, the existence of different bifurcations is i nvestigated numerically. Using Floquet spectral analysis, we give a complet e characterization of the most relevant bifurcations, and we find (spatial) symmetry-breaking bifurcations that are linked to breather mobility, just as it was found in Hamiltonian systems by other authors. In this way moving breathers are shown to exist even at remarkably high levels of discretenes s. We study mobile breathers and characterize them in terms of the phonon r adiation they emit, which explains successfully the way in which they inter act. For instance, it is possible to form "bound states" of moving breather s, through the interaction of their phonon tails. Over all, both stationary and moving breathers are found to be generic localized states over large v alues of C, and they are shown to be robust against low temperature fluctua tions.