We present a general construction of diagrammatic two-particle approximations consistent with the one-particle functions so that both produce qualitatively the same quantum critical behavior in thermodynamically equivalent descriptions. The general scheme is applied on the single-impurity Anderson model to derive qualitatively the same Kondo critical behavior from the spectral function and the magnetic susceptibility.
Typical temperature behavior of the spectral function of strongly correlated electron systems with no long-range order. The combined effect of strong electron repulsion and thermal fluctuations expel electrons from the Fermi energy to satellite Hubbard bands. Lowering the temperature enhances the quantum coherence and a narrow central quasiparticle peak starts to develop reflecting formation of local magnetic moments in metals while the Hubbard bands remains present. The energy unit is the effective bandwidth of the metal.
Contact person: Václav Janiš