Turbulent thermalization process in heavy-ion collisions at ultrarelativistic energies

TL;DR

This study uses large-scale lattice simulations to analyze the non-equilibrium thermalization process in ultrarelativistic heavy-ion collisions, revealing self-similar turbulent dynamics consistent with the bottom-up scenario.

Contribution

It provides the first large-scale classical Yang-Mills simulation demonstrating the universal, turbulence-driven thermalization process in high-energy heavy-ion collisions.

Findings

Dynamics become independent of initial conditions after transient phase.

System exhibits self-similar wave turbulence behavior.

Results align with the bottom-up thermalization scenario.

Abstract

The non-equilibrium evolution of heavy-ion collisions is studied in the limit of weak coupling at very high energy employing lattice simulations of the classical Yang-Mills equations. Performing the largest classical-statistical simulations to date, we find that the dynamics of the longitudinally expanding plasma becomes independent of the details of the initial conditions. After a transient regime dominated by plasma instabilities and free streaming, the subsequent space-time evolution is governed by a nonthermal fixed point, where the system exhibits the self-similar dynamics characteristic of wave turbulence. This allows us to distinguish between different kinetic scenarios in the classical regime. Within the accuracy of our simulations, the scaling behavior found is consistent with the ``bottom-up" thermalization scenario.