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HK: Fachverband Physik der Hadronen und Kerne
HK 57: Heavy-Ion Collisions and QCD Phases XIII
HK 57.3: Talk
Friday, April 3, 2020, 11:45–12:00, J-HS G
Dynamic critical exponents from classical-statistical spectral functions — •Dominik Schweitzer1, Sören Schlichting2, and Lorenz von Smekal1 — 1Institut für Theoretische Physik, Justus-Liebig-Universität Gießen — 2Fakultät für Physik, Universität Bielefeld
When a thermodynamic system comes close to a critical point, large fluctuations lead to scale-invariant physics, not only in static but also dynamic observables, such as spectral functions. Such observables can be measured by a range of experiments, and will become relevant in future heavy-ion collision experiments closing in on the QCD critical point.
We investigate the dynamic critical behavior of self-interacting scalar fields with Z2 symmetry and hence the same static universal behavior as QCD at the critical endpoint. We calculate spectral functions of the order parameter at zero and non-vanishing momenta from classical statistical lattice simulations in real time. In the high-temperature phase, we find that the spectral functions are well described by relativistic quasi-particle peaks; at low temperatures, we find an additional mode with a different dispersion relation. Close to the transition temperature, we see a strong IR contribution building up.
Considering the equations of motion for a closed system as well as a system coupled to a heat bath, we determine the underlying universal scaling functions in the critical region, and extract the dynamic critical exponents z for two different dynamic universality classes, Model A & C.