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arXiv · 2312.04760

Far-off-equilibrium early-stage dynamics in high-energy nuclear collisions

Chandrodoy Chattopadhyay·Ulrich Heinz·Thomas Schaefer
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Abstract

We explore the far-off-equilibrium aspects of the (1+1)-dimensional early-stage evolution of a weakly-coupled quark-gluon plasma using kinetic theory and hydrodynamics. For a large set of far-off-equilibrium initial conditions the system exhibits a peculiar phenomenon where its total equilibrium entropy decreases with time. Using a non-equilibrium definition of entropy based on Boltzmann's H-function, we demonstrate how this apparently anomalous behavior is consistent with the second law of thermodynamics. We also use the H-function to formulate `maximum-entropy' hydrodynamics, a far-off-equilibrium macroscopic theory that can describe both free-streaming and near-equilibrium regimes of quark-gluon plasma in a single framework.

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Chandrodoy Chattopadhyay, Ulrich Heinz, Thomas Schaefer. 2023-12-08. Far-off-equilibrium early-stage dynamics in high-energy nuclear collisions. https://arxiv.org/abs/2312.04760

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