Exact solutions of the Boltzmann equation and optimized hydrodynamic approaches for relativistic heavy-ion collisions

TL;DR

This paper discusses exact solutions to the relativistic Boltzmann equation and their use in developing optimized hydrodynamic models to improve the accuracy of simulations in relativistic heavy-ion collision experiments.

Contribution

It introduces exact solutions of the relativistic Boltzmann equation in anisotropic systems and applies them to refine hydrodynamic approaches for heavy-ion collisions.

Findings

Exact solutions serve as benchmarks for hydrodynamic models.

Optimized hydrodynamics better captures anisotropic expansion.

Progress towards more precise relativistic fluid dynamics models.

Abstract

Several recent results are reported from work aiming to improve the quantitative precision of relativistic viscous fluid dynamics for relativistic heavy-ion collisions. The dense matter created in such collisions expands in a highly anisotropic manner. Due to viscous effects this also renders the local momentum distribution anisotropic. Optimized hydrodynamic approaches account for these anisotropies already at leading order in a gradient expansion. Recently discovered exact solutions of the relativistic Boltzmann equation in anisotropically expanding systems provide a powerful testbed for such improved hydrodynamic approximations. We present the latest status of our quest for a formulation of relativistic viscous fluid dynamics that is optimized for applications to relativistic heavy-ion collisions.