Looking for soliton signatures in polaron Bloch states

We have recently made considerable progress on the classic problem of polaron theory using a variety of variational states to obtain the full ground-state energy band of the system. One of the ansatz states we have implemented was first proposed by Toyozawa and is closely related to localized states based on the Davydov ansatz. Our goal in this paper is to test certain archetypical characteristics of the soliton theories associated with localized states against the variational results based on the Toyozawa method. In the Toyozawa method, the internal structure of the complete set of polaron Bloch states for the ground-state energy band is represented by variational surfaces giving the optimal values of the complete set of exciton and phonon amplitudes for every value of the joint exciton-phonon crystal momentum kappa and the exciton and phonon subsystem wave vectors k and ri. Here we focus on those aspects of the band-theoretic results that show the greatest promise for a. favorable comparison with soliton theory. We find that quantitative characteristics typical of solitons do not survive this close scrutiny. Copyright (C) 1998 Elsevier Science B.V.