Thermodynamically consistent description of criticality in models of correlated electrons

0482121 - FZÚ 2018 RIV US eng J - Journal Article
Janiš, Václav - Kauch, Anna - Pokorný, Vladislav
Thermodynamically consistent description of criticality in models of correlated electrons.
Physical Review B. Roč. 95, č. 4 (2017), s. 1-14, č. článku 045108. ISSN 2469-9950. E-ISSN 2469-9969
R&D Projects: GA ČR GA15-14259S
Institutional support: RVO:68378271
Keywords : conserving approximations * Anderson model * Hubbard model * parquet equations
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 3.813, year: 2017

Criticality in models of correlated electrons 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 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 scale from the spectral function and the magnetic susceptibility.

Permanent Link: http://hdl.handle.net/11104/0277529