Two and Many Impurity Effects in Soliton Dynamics

Abstract

Since perfect systems are an idealization never found in nature, the study of the effects of disorder on them is of paramount importance. In particular, nonlinear models, which have been very much fruitful in many fields of physics,¹ have been the subject of an intense effort in this direction.² A complete description of this problem can only be achieved through a step-by-step analysis, in which the influence of one, two, and many impurities are addresed separately, one after the other. In this fashion, the knowledge acquired on the one-impurity problem helps understand the new features arising when two impurities are present, and this can be later used to account for the unavoidable cooperative effects which appear in a system with many impurities present. This work is a part of such a project, devoted to the study of nonlinear excitation dynamics in Nonlinear Klein-Gordon models. The one impurity problem is discussed in another contribution in this volume,³ and here we deal with the remaining stages of the work.