WHAT DO POLARONS OWE TO THEIR HARMONIC ORIGINS

Polaron (and related) soliton concepts are based on the assumption tha t quasiparticles are in linear interaction with harmonic oscillators. The discrete nonlinear Schrodinger equation and its semiclassical rela tives are also based on this assumption. Study of the effects of nonli nearity in interaction, and anharmonicity in the restoring force of th e oscillators, has led to notable results such as saturation of nonlin earities and counterintuitive pheonomena such as destruction of self-t rapping on increasing the nonlinearity. We report on these and related results, The general aim of the investigation is to determine what po larons owe to their harmonic (and linear) origins and how a generalize d conceptual framework may be built which includes known polaron physi cs as a subset. Copyright (C) 1998 Elsevier Science B.V.