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K. Boguslavski:
"Dynamics of non-Abelian plasmas: spectral functions and transport coefficients";
Vortrag: Seminar at TU Munich, Munich, Germany (eingeladen); 06.05.2019 - 10.05.2019.

A method is presented to extract the (single-particle) spectral function of a non-Abelian gauge theory in the region where occupation numbers are high. Although we apply it to a 3+1 dimensional (3+1D) system far from equilibrium in a self-similar regime, the extracted spectral function can be understood within the hard thermal loop (HTL) formalism and can thus be connected to thermal equilibrium at high temperatures. We also extract the heavy-quark momentum diffusion coefficient in this system. We observe that its time-evolution is consistent with a t^(-5/7) power law, as predicted by HTL, which is an important step forward in understanding the evolution of the diffusion coefficient at initial stages. Going beyond the range of applicability of HTL, we measure the spectral function in 2+1D. We show that quasi-particle assumptions become invalid at low momenta p <= m below the mass scale. This challenges our detailed understanding of phenomena like plasma instabilities at initial stages that are mostly based on HTL calculations of highly anisotropic gluonic matter.