Linking the hydrodynamic and kinetic description of a dissipative relativistic conformal theory

TL;DR

This paper develops a method to connect hydrodynamic and kinetic descriptions of relativistic conformal fluids using entropy production principles, providing explicit distribution functions and constitutive relations relevant for heavy-ion collision modeling.

Contribution

It introduces a generalized linking method between hydrodynamics and kinetic theory for conformal fluids, extending Grad's ansatz with explicit distribution functions.

Findings

Derived explicit distribution functions for conformal fluids.

Established constitutive relations matching previous dissipative theories.

Potential applications in modeling freeze-out in heavy-ion collisions.

Abstract

We use the entropy production variational method to associate a one particle distribution function to the assumed known energy-momentum and entropy currents describing a relativistic conformal fluid. Assuming a simple form for the collision operator we find this one particle distribution function explicitly, and show that this method of linking the hydro and kinetic description is a non trivial generalization of Grad's ansatz. The resulting constitutive relations are the same as in the conformal dissipative type theories discussed in J. Peralta-Ramos and E. Calzetta, Phys. Rev. D {\bfseries 80}, 126002 (2009). Our results may prove useful in the description of freeze-out in ultrarelativistic heavy-ion collisions.