Non-thermal fixed points: Universal dynamics far from equilibrium

Understand

In this article we give an overview of the concept of universal dynamics near non-thermal fixed points in isolated quantum many-body systems.

• We outline a non-perturbative kinetic theory derived within a Schwinger-Keldysh closed-time path-integral approach, as well as a low-energy effective field theory which enable us to predict the universal scaling exponents characterizing the time evolution at the fixed point.
• We discuss the role of wave-turbulent transport in the context of such fixed points and discuss universal scaling evolution of systems bearing ensembles of (quasi) topological defects.
• This is rounded off by the recently introduced concept of prescaling as a generic feature of the evolution towards a non-thermal fixed point.