The renormalization group plays an essential role in many areas of physics, both
conceptually and as a practical tool to determine the long-distance low-energy properties of …

In this report we review recent progress achieved in the understanding of heavy quarkonium
under extreme conditions from a theory perspective. Its focus lies both on quarkonium …

Simulations of finite temperature quantum systems provide imaginary frequency Green's
functions that correspond one to one to experimentally measurable real-frequency spectral …

The precision with which hadronic vacuum polarization (HVP) is obtained determines how
accurately important observables, such as the muon anomalous magnetic moment a μ or the …

Green's functions of fermions are described by matrix-valued Herglotz-Nevanlinna functions.
Since analytic continuation is fundamentally an ill-posed problem, the causal space …

A bstract The computation of the parton distribution functions (PDF) or distribution
amplitudes (DA) of hadrons from first principles lattice QCD constitutes a central open …

A bstract This work employs the spectral reconstruction approach of ref.[1] to determine an
inclusive rate in the 1+ 1 dimensional O (3) non-linear σ-model, analogous to the QCD part …

We review the recent status of the QCD sum rule approach to study the properties of
hadrons in vacuum and in hot or dense matter. Special focus is laid on the progress made in …

Finite-temperature quantum field theories are formulated in terms of Green's functions and
self-energies on the Matsubara axis. In multiorbital systems, these quantities are related to …

We review the current state of research on electromagnetic probes in the context of heavy-
ion collisions. The focus is on thermal photons and dileptons which provide unique insights …