Prof. RNDr. Václav Janiš, DrSc.

Science is what we have learned about how to keep from fooling ourselves. (R. Feynman)

Research area & expertise:
Condensed Matter Theory

Research interests:
Model description of electron correlations, Hubbard and Anderson impurity models, collective and cooperative phenomena, transition from weak to strong coupling regimes, breakdown of Fermi-liquid phase, (dynamical) mean-field theory for intermediate and strong coupling, Kondo and insulating regimes; implementation of electron correlations in realistic calculation schemes
Quantitative description of quantum criticality, interaction-driven quantum phase transitions in metals, effects of noncommutativity of relevant operators on critical behavior, formation of bound and resonant pair states, structure of order parameters of quantum phases, transverse magnetic order, superconductivity
Vertex corrections in the electrical conductivity in impure metals, quantum diffusion and coherence, diagrammatic theory of weak and strong electron localization, metal-insulator transition
Mean-field theory based on real replicas in the thermodynamic approach of Thouless, Anderson and Palmer for Ising and Heisenberg spin glasses and related models
Feynman diagrams and many-body Green functions for nonrelativistic quantum interacting systems, advanced approximations for two-particle Green functions, vertex corrections, parquet approach to two-particle vertex functions
Interacting quantum dots attached to superconducting leads, Andreev bound states, 0-pi transition, perturbation theory with anomalous functions