Fermi-Luttinger liquid: Spectral function of interacting one-dimensional fermions

We evaluate the spectral function of interacting fermions in one dimension. Contrary to the Tomonaga-Luttinger model, our treatment accounts for the nonlinearity of the free fermion spectrum. In a striking departure from the Luttinger liquid theory, the spectrum nonlinearity restores the main feature of the Fermi liquid: a Lorentzian peak in the spectral function on the particle mass shell. At the same time, the spectral function displays a power-law singularity on the hole mass shell, similar to that in the Luttinger liquid.