Transport properties of the strongly

The transport properties of various systems are studied here in the context of three different models. These are: (i) the disordered Hubbard model ap-plicable to correlated binary alloys with a general disorder, (ii) the Anderson model used in describing the Kondo physics of a quantum dot connected to the external superconducting leads, and (iii) the Ranninger-Robaszkiewicz model applied to the study of optical properties of the system with pre-formed electron pairs above the temperature of transition to the supercon-ducting state. We calculate the density of states, specific heat, the Wilson ratio and conductivity of the correlated binary alloy with off-diagonal disor-der. We investigate the conditions under which the Kondo peak appears in the density of states and in the conductance of a dot coupled to the exter-nal superconducting leads. We analyze the effect of the pseudogap on the optical spectra in the high temperature superconductors described by the boson-fermion model. Key words: coherent potential approximation, slave bosons, non-equilibrium transport, quantum dot, continuous transformation, pseudogap PACS: 71.10.-w, 72.10.-d, 73.23.-b, 74.20.-z 1