Thermodynamically consistent description of quantum criticality in models of correlated electrons
by
Prof. Vaclav Janis, University of Prague
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Europe/Berlin
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Room 222
Jungiusstr. 9
Description
Quantum criticality emerges in proximity of a low-temperature singularity in a two-particle Green function. Such singularities are generally related to a symmetry breaking of the one-particle self-energy. A consistent description demands that the symmetry breaking in the self-energy emerges at the critical point of the respective two-particle function. This cannot easily be achieved in models of correlated electrons, since there are two ways connecting one- and two-electron functions that cannot be made fully equivalent in approximations. We present a general construction of diagrammatic two-particle approximations consistent with the one-particle functions that lead to qualitatively the same quantum critical behavior in thermodynamically equivalent descriptions. We apply the scheme on the single-impurity Anderson model to derive the Kondo critical scale from both spectral and thermodynamic functions.
