strongly correlated materials revealed a number of unexpected intriguing phenomena which can not be explained within the standard theory of solids. [@Ashcroft] The paradigm of correlation effects is based on the Mott insulating state and the Mott-Hubbard metal-insulator transition,[@imadaRMP; @mott] but a key role is also played by high-temperature superconductivity in copper oxides [@Bednorz86; @Anderson87] and the unconventional superconductivity at the edge of a magnetic phase observed in heavy fermions.[@Flouquet06; @CePd2Si2] More recently, the partnership between exotic superconductivity, strong correlations and magnetism has been strengthened by the discoveries in the iron-based superconductors,[@Hosono08] in the alkali-doped fullerides[@Takabayashi09; @Capone09] and possibly also in the molecular conductors based on aromatic molecules.[@kubozono10; @Giovannetti11; @nomura11]

A common companion of Mott physics and anomalous superconductivity is the deviation from the standard Fermi-Liquid (FL) theory in the metallic phase, or non-Fermi-liquid (NFL) behavior.[@nflstewart] The FL theory describes a system of interacting fermions as a collection of renormalized non-interacting [*quasi-particles*]{} which propagate coherently in the solid.[@nozieres97] The main qualitative effect of the electron-electron correlations is to enhance the effective mass and accordingly reduce the coherence of the Fermi gas. This reflects in a reduction of the coherence temperature, the scale at which the thermal fluctuations destroy the coherent 