Speaker: F. Mertens

Abstract: We consider atomic chains with nearest-neighbor interaction potentials with cubic and quartic anharmonicities. We use the Quasicontinuum Approach and derive analytic expressions for bright and dark envelope solitons. Moreover we derive and apply a numerical iteration procedure in order to take into account discreteness effects in a systematic way. This procedure yields envelope solitons with a width in the order of the lattice constant that can be compared with intrinsic localized modes derived by other authors. All our solutions are tested by molecular dynamics simulations.

We consider square lattices with anharmonic nearest and next-nearest interactions. We study envelope solitons which are localized in the direction of their motion and periodically modulated along the perpendicular direction. In the quasi-monochromatic approximation and low-amplitude regime a system of two coupled nonlinear Schroedinger equations in obtained for the envelopes of the longitudinal and transversal displacements. The stability of two solution classes is tested by molecular dynamics simulations.

MOBIL. Moving Breathers in Inhomogeneous Lattices. Workshop at Sevilla, 21-22 February 2003.