A PROPAGATING SELF-LOCALIZED MODE IN A ONE-DIMENSIONAL LATTICE WITH QUARTIC ANHARMONICITY

A pure one-dimensional lattice with quartic anharmonicity and nearest-neighbor in-teractions is shown to exhibit a fairly well-defined propagating self-localized mode above the harmonic frequency band. This is a propagating-mode version of a sta-tionary, immobile p-like self-localized mode having the displacement pattern (…, 0, 0, −1/2, 1/2, 0, 0, …) in the extreme localization limit. An approximate analytical expression for localized-mode envelope functions is obtained in a form similar to that of the Ablowitz-Ladik lattice solitons. Nonlinear eigenvalue equations are studied by using the method of lattice Green's functions, by which an approximate analytical ex-pression for the dispersion relation of the localized mode is also obtained. © 1990, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.