On modelling adiabatic N - soliton interactions in external potentials
  We analyze perturbed version of the complex Toda chain (CTC) in an attempt to describe the adiabatic N - soliton train interactions of the perturbed nonlinear Schr\"odinger equation (NLS). We study perturbations with weak quadratic and periodic external potentials by both analytical and numerical means. The perturbed CTC adequately models the N - soliton train dynamics for both types of potentials. As an application of the developed theory we consider the dynamics of a train of matter - wave solitons confined in a parabolic trap and optical lattice, as well as tilted periodic potential. 
V. S. Gerdjikov, B. B. Baizakov and M. Salerno