A new exact solution of the relativistic Boltzmann equation and its hydrodynamic limit

TL;DR

This paper introduces an exact solution to the relativistic Boltzmann equation for Gubser flow, enabling precise testing of hydrodynamic models against non-equilibrium dynamics in high-energy collision scenarios.

Contribution

It provides the first exact solution for the relativistic Boltzmann equation under Gubser flow, facilitating validation of hydrodynamic approximations.

Findings

Exact non-equilibrium solution for Gubser flow

Comparison shows hydrodynamics accuracy varies with viscosity

Useful for testing relativistic hydrodynamic models

Abstract

We present an exact solution of the relativistic Boltzmann equation for a system undergoing boost-invariant longitudinal and azimuthally symmetric transverse flow ("Gubser flow"). The resulting exact non-equilibrium dynamics is compared to 1st- and 2nd-order relativistic hydrodynamic approximations for various shear viscosity to entropy density ratios. This novel solution can be used to test the validity and accuracy of different hydrodynamic approximations in conditions similar to those generated in relativistic heavy-ion collisions.