SMuK 2021 – scientific programme
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MP: Fachverband Theoretische und Mathematische Grundlagen der Physik
MP 4: AdS-CFT II
MP 4.1: Talk
Tuesday, August 31, 2021, 14:00–14:25, H7
Effective Transport Coefficients in Time-Dependent Field Theory: Far-from-Equilibrium Shear Viscosity via Holography — •Michael Florian Wondrak1,2, Matthias Kaminski3, and Marcus Bleicher1,2,4 — 1Helmholtz Forschungsakademie Hessen für FAIR, Frankfurt am Main, Germany — 2Institut für Theoretische Physik, Goethe-Universität Frankfurt am Main, Germany — 3Department of Physics and Astronomy, University of Alabama, Tuscaloosa, USA — 4GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
The gauge/gravity duality offers an elegant way of characterizing field theories at strong coupling. Close to equilibrium, hydrodynamic transport coefficients have been calculated successfully. Far from equilibrium, the main focus has been on thermalization based on the thermodynamic properties of the theory.
In this talk, we generalize transport coefficients from the near-equilibrium to the highly dynamic regime. Our approach is based on Wigner transformations in combination with Green–Kubo relations. Furthermore, we contrast field-theory and bulk-spacetime generalizations of the entropy density.
We consider a conformal field theory at time-dependent temperature and chemical potential corresponding to an accreting black hole in the bulk. At early and late times, we consistently recover the well-known near equilibrium value of the ratio of shear viscosity and entropy density. During the dynamic regime, there are substantial deviations of order unity.