High-order perturbation expansion: application to a quantum thermodynamical system in one space dimension

Abstract

The recently proposed method for investigating the large-order behaviour of the perturbative expansion is applied to a quantum thermodynamical system of interacting bosons in one space dimension. The method makes essential use of the classical solutions for the total Hamiltonian and of the oscillations about them. The contribution of these oscillations is calculated by using a canonical transformation related to the inverse scattering method, the relevant equation being the nonlinear Schrodinger equation. The leading-order corrections to the Bose-Einstein distribution are obtained explicitly.