The correlation functions of quantum systems—central objects in quantum field theories—
are defined in high-dimensional space-time domains. Their numerical treatment thus suffers …

We present and implement a parquet approximation within the dual-fermion formalism
based on a partial bosonization of the dual vertex function which substantially reduces the …

The fundamental idea of the excitonic insulator (EI) driven by electron–hole correlations in
narrow-gap semiconductors or semimetals was originally proposed in the 1960s, and only …

We generalize the formalism of the dynamical vertex approximation (D Γ A)—a
diagrammatic extension of the dynamical mean-field theory (DMFT)—to treat magnetically …

We study the conditions to realize an excitonic condensed phase in an electron-hole bilayer
system with local Hubbard-like interactions at half-filling, where we can address the interplay …

The low-energy excitation properties of the excitonic condensate in the semimetal and
semiconducting materials are inspected in the extended Falicov-Kimball model. In the …

The influence of phonons on the low-energy excitonic excitations at zero temperature in the
extended Falicov-Kimball model has been investigated. In the framework of the unrestricted …

We investigate magnetic-field effects on a two-orbital Hubbard model that describes multiple
spin states. The exploration of spin-state degrees of freedom in perovskite-type cobalt …

We present a dynamical mean-field study of antiferromagnetic magnons in a one-, two-, and
three-orbital Hubbard model of square and bcc cubic lattice at intermediate coupling …

We discuss the thermodynamic and magnetic properties of a competing high-spin/low-spin
two-orbital two-electron model on a square lattice possibly relevant to the nickelates such as …