ABSENCE OF BACKSCATTERING AT INTEGRABLE IMPURITIES IN ONE-DIMENSIONALQUANTUM MANY-BODY SYSTEMS

We study interacting one-dimensional (1D) quantum lattice gases with i ntegrable impurities. These model Hamiltonians can be derived using th e quantum inverse scattering method for inhomogeneous models and are b y construction integrable. The absence of backscattering at the impuri ties is shown to be the characteristic feature of these disordered sys tems. The value of the effective carrier charge and the Sutherland-Sha stry relation are derived for the half-filled XXX model and are shown to be independent of the impurity concentration and strength. For the half-filled XXZ model we show that there is no enhancement of the pers istent currents for repulsive interactions. For attractive interaction s we identify a crossover regime beyond which enhancement of the curre nts is observed.