Physical review. B, Solid state
Soliton Green's functions in the one-dimensional Fermi gas with backward scattering
P. Schlottmann
Abstract
The energy spectrum of the one-dimensional Fermi gas and the one-particle Green's functions are calculated within the one-body (soliton) approximation by perturbation expansion from the particular limit solved by Luther and Emery. Fermion properties, in particular the Ward identity, of the Luttinger model are explicitly used to calculate the backward scattering amplitude. The gap in the excitation spectrum is in agreement with the results of other authors. At nonzero temperature the quasiparticles have a lifetime. As a consequence, for instance, the specific heat at low temperatures is linear in $T$ and not exponentially activated.