title: Finite-frequency optical absorption in 1D conductors and mott-hubbard insulators
abstract: The frequency-dependent conductivity is studied for the one-dimensional Hubbard model, using a selection rule, the Bethe ansatz, and symmetries associated with conservation laws. For densities where the system is metallic the absorption spectrum has two contributions, a Drude peak at omega = 0 separated by a pseudogap from a broad absorption band whose lower edge is characterized by a nonclassical critical exponent. Our findings shed new light on the "far infrared puzzle" and other optical properties of metallic organic chain compounds.
authors.affiliation: CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 and Department of Physics, University of Evora, Apartado 94, P-7002-554 Evora, Portugal.
authors.initials: JM
authors.lastname: Carmelo
authors.initials: NM
authors.lastname: Peres
authors.initials: PD
authors.lastname: Sacramento