# Towards a unified lattice kinetic scheme for relativistic hydrodynamics

## TL;DR

This paper develops a unified relativistic lattice kinetic scheme for particles with finite mass, bridging the gap between massive and ultra-relativistic regimes, validated through numerical benchmarks.

## Contribution

It introduces a systematic derivation of relativistic lattice kinetic equations applicable to both massive and near-massless particles, expanding previous models.

## Key findings

- Accurate numerical validation against standard relativistic fluid dynamics benchmarks.
- Effective discretization of the relativistic Boltzmann equation on Cartesian lattices.
- Demonstrates the model's applicability across a wide range of particle masses.

## Abstract

We present a systematic derivation of relativistic lattice kinetic equations for finite-mass particles, reaching close to the zero-mass ultra-relativistic regime treated in the previous literature. Starting from an expansion of the Maxwell-Juettner distribution on orthogonal polynomials, we perform a Gauss-type quadrature procedure and discretize the relativistic Boltzmann equation on space-filling Cartesian lattices. The model is validated through numerical comparison with standard benchmark tests and solvers in relativistic fluid dynamics such as Boltzmann approach multiparton scattering (BAMPS) and previous relativistic lattice Boltzmann models. This work provides a significant step towards the formulation of a unified relativistic lattice kinetic scheme, covering both massive and near-massless particles regimes.