Nonextensive hydrodynamics for relativistic heavy-ion collisions

TL;DR

This paper introduces a nonextensive hydrodynamical model based on Tsallis statistics for relativistic heavy-ion collisions, providing a new perspective on local equilibrium and dissipation in such systems.

Contribution

It proposes a nonextensive hydrodynamics framework that replaces traditional local thermal equilibrium with a nonextensive parameter, linking it to dissipative hydrodynamics.

Findings

Derived simple expressions for dissipative entropy current.

Predicted ratios of bulk and shear viscosities to entropy density.

Established correspondence between nonextensive and dissipative hydrodynamics.

Abstract

The nonextensive one-dimensional version of a hydrodynamical model for multiparticle production processes is proposed and discussed. It is based on nonextensive statistics assumed in the form proposed by Tsallis and characterized by a nonextensivity parameter $q$. In this formulation the parameter $q$ characterizes some specific form of local equilibrium which is characteristic for the nonextensive thermodynamics and which replaces the usual local thermal equilibrium assumption of the usual hydrodynamical models. We argue that there is correspondence between the perfect nonextensive hydrodynamics and the usual dissipative hydrodynamics. It leads to simple expression for dissipative entropy current and allows for predictions for the ratio of bulk and shear viscosities to entropy density, $\zeta/s$ and $\eta/s$, to be made.