Collective phenomena in quantum many-body systems are often described in terms of hydrodynamics, an appropriate framework when the involved particle numbers are effectively macroscopic. Motivated by the recent observation of collective phenomena in high-energy proton-proton and proton-nucleus collisions, where particle numbers are small and a fluid description is a priori inapplicable, we...
A very striking manifestation of collective behaviour of many particles is the emergence of hydrodynamics, the effective description of a system as a fluid. In addition to classical systems, hydrodynamic expansion has also been observed in different many-body quantum systems, ranging from heavy ion collisions (1) to ultracold quantum gases (2). However, the fundamental requirements for...
We compute gluon, fermion and scalar spectral functions in highly occupied systems far from equilibrium using classical-statistical lattice simulations. We compare our nonperturbative results for fermion and gluon spectral functions in two and three spatial dimensions with perturbative hard loop calculations, extract the full momentum dependence of the damping rates of quasiparticles and...
Heavy quarks (i.e. charm and beauty) are powerful tools to characterize the quark-gluon plasma (QGP) produced in heavy-ion collisions. Although they are initially produced out of kinetic equilibrium via hard partonic scattering processes, recent measurements of anisotropic flow of charmed hadrons [1] pose the question regarding the possible thermalization of heavy quarks in the medium. Our...
Science is entering a new era in the investigation of nuclear matter, driven by a wealth of precision data from the JLab, HERA, RHIC & LHC experiments. The nCTEQ project employs cutting-edge theoretical techniques to analyse these data sets comprehensively. In my talk I will review some of the most recent advances in the nCTEQ approach including 1) the addition of heavy-quark production data...
When coming close to an atom, a muon can be captured by the nucleus and form a hydrogen-like muonic ion, which is typically also surrounded by atomic electrons. This atomic system is commonly referred to as a muonic atom. Due to the muon's high mass, it is located much closer to the nucleus; and, especially for heavy nuclei, this results in big nuclear size effects and a strong dependence of...
Controlling interactions is a key to experimentally study far-from-equilibrium dynamics in isolated quantum systems. Here we present two methods of changing the symmetry properties of Heisenberg spin systems implemented with Rydberg atoms. By using time-periodic driving, a naturally given many-body Hamiltonian of a closed quantum system can be
transformed into an effective target Hamiltonian....
Tabletop experiments with ultracold atoms provide the opportunity to simulate non-perturbative phenomena in quantum field theory. In the proposed experiment, we consider two weakly coupled, one-dimensional Bose-Einstein condensates. The evolution of the population imbalance, in the mean field approximation, is described by a scalar field moving in an effective potential. We discuss in detail...
Lasers providing ultra-strong fields might allow for the first time a verification of electron-positron pair production via the Schwinger effect. Recent theoretical investigations have elucidated many aspects of this essentially non-perturbative effect. However, there is, at least, one fundamental question which has remained elusive: What is the formation time of the electron (or,...
