CHARGE-SPIN SEPARATION AND THE SPECTRAL PROPERTIES OF LUTTINGER LIQUIDS

We compute the spectral function rho(q,omega) of the one-dimensional Luttinger model. We discuss the distinct influences of charge-spin separation and of the anomalous dimensions of the fermion operators and their evolution with correlation strength. Charge-spin separation shows up in finite spectral weight at frequencies between upsilon(sigma)q and upsilon(rho)q, where upsilon(sigma) and upsilon(rho) are the velocities of spin and charge fluctuations, while spectral weight above upsilon(rho)q and below -upsilon(rho)q is generated by the hybridization of the Fermi surface at +/-k(F) by interactions. There are nonuniversal power-law singularities at these special frequencies. We discuss the consistency of recent photoemission experiments on Low-dimensional conductors with a Luttinger-liquid picture, which then would suggest very strong long-range interactions. It is pointed out that many-particle correlation functions in principle exhibit similar singularities, but they probe different and complementary aspects of the Fermi-surface interactions.