SAMOP 2023 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 22: Poster II

Q 22.13: Poster

Dienstag, 7. März 2023, 16:30–19:00, Empore Lichthof

A functional renormalization group approach to non-thermal fixed points in an ultracold Bose gas — •Aleksandr N. Mikheev^1,2, Jan M. Pawlowski^2,3, and Thomas Gasenzer^1,2 — ¹Kirchhoff-Institut für Physik, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany — ²Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany — ³ExtreMe Matter Institute EMMI, GSI, Planckstraße 1, 64291 Darmstadt, Germany

Classification and understanding of scaling solutions in closed quantum systems far from thermal equilibrium, known as non-thermal fixed points, is one of the open problems in non-equilibrium quantum many-body theory. The usual method involves searching for possible self-similar solutions to a (non-perturbative) evolution equation, e.g., Boltzmann or Kadanoff-Baym, starting from a far-from-equilibrium initial condition. We outline an alternative approach based on the correspondence between scaling and fixed points of the renormalization group. Using an ultracold Bose gas as an example we show how possible far-from-equilibrium scaling solutions can be systematically obtained by solving fixed-point renormalization-group equations.