For decades, frustrated quantum magnets have been a seed for scientific progress and
innovation in condensed matter. As much as the numerical tools for low-dimensional …

The Hubbard model represents the fundamental model for interacting quantum systems and
electronic correlations. Using the two-dimensional half-filled Hubbard model at weak …

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 …

Within many-body perturbation theory, Hedin's formalism offers a systematic way to
iteratively compute the self-energy Σ of any dynamically correlated interacting system …

Multipoint vertex functions, and the four-point vertex in particular, are crucial ingredients in
many-body theory. Recent years have seen significant algorithmic progress toward …

While calculations and measurements of single-particle spectral properties often offer the
most direct route to study correlated electron systems, the underlying physics may remain …

We study the microscopic mechanism controlling the interplay between local charge and
local spin fluctuations in correlated electron systems via a thorough investigation of the …

Conceptually, the Matsubara formalism (MF), using imaginary frequencies, and the Keldysh
formalism (KF), formulated in real frequencies, give equivalent results for systems in thermal …

In the field of quantum many-body physics, the spectral (or Lehmann) representation
simplifies the calculation of Matsubara $ n $-point correlation functions if the eigensystem of …

Electron correlation in finite and extended systems is often described in an effective single-
particle framework within the GW approximation. Here, we use the statically screened …