Movingd-Dimensional Nonlinear Localized Modes and Envelope Solitons in Nonlinear Exciton Transfer Models in Lattices

Several lattice models of nonlinear excitation transfer in a d -dimensional version of the simple cubic lattice are prcsented to show the existence of exact moving d -dimensional nonlinear localized mode solutions. The eigenfrequencies of the localized modes appear either below or above the linear exciton frequency band. Profile functions of the four types of localized modes considered here are described by the sech-function, the square of the sech-function, the cosech-function and the square of the cosech-function, of which the first and the third are identified as envelope solitons in the d -dimensional lattice.