An expanded Luttinger model

This paper generalizes Luttinger's model by introducing curvature (d2ε (k) dk2 ≠ 0 ) into the kinetic energy. An exact solution for arbitrary interactions is still possible in principle, but it now requires disentangling the eigenvalue spectrum of an harmonic string of interacting boson fields at each value of q. The additional boson fields, extracted from the excitation spectrum of the Fermi sea, are self-selected according to the nature and strength of the dispersion.