## Seminar on Theoretical Nuclear Physics

## 28.01.14 16:15

# The long-wavelength limit of the Boltzmann equation: recent insights in deriving relativistic dissipative fluid dynamics

## Dirk Rischke (Uni Frankfurt)

Abstract

In this talk, I present a new derivation of dissipative relativistic fluid dynamics from the Boltzmann equation via the method of moments. In constrast to previous derivations, the single-particle distribution function is not subjected to a truncation in an uncontrolled way. Instead, it is expanded in terms of irreducible tensors in momentum-space and orthogonal polynomials in energy. The infinite system of moment equations, which is equivalent to the Boltzmann equation, can then be truncated in a controlled way by considering only the slowest microscopic time scale and a rigorous power-counting in Knudsen and inverse Reynolds numbers. I demonstrate that agreement with microscopic solutions of the Boltzmann equation for specific test problems can be improved by going beyond the traditional 14-moment approximation.

(Seminarraum II)