Universality in non equilibrium dynamics

We study strong cooling quench and demonstrate universal scaling of dynamics of the induced non-equilibrium dynamics in time and space.  The time evolution within the scaling period is described by a single universal function and scaling exponent, independent of the species of the initial state which constitutes a crucial step in the verification of universality far from equilibrium [1]. Out experiment suggest that the dynamics is governed by a non-equilibrium generalization of Renormalization and can be described by the approach of a non-thermal fixed point. This suggests a comprehensive classification of systems far from equilibrium based on their universal properties similar to the universality classes in phase transitions.  Similarly, this can be the basis for a new type of quantum simulation that let us explore a large variety of systems at different scales.

Work performed in collaboration with the groupsof Th. Gasenzer und J. Berges (Heidelberg). Supported by DFG-FWF: SFB ISOQUANT: and the EU: ERC-AdG QuantumRelax

 [1] S. Erne et al. Nature 253, 225 (2018).