Studying the validity of relativistic hydrodynamics with a new exact solution of the Boltzmann equation

Gabriel S. Denicol, Ulrich W. Heinz, Mauricio Martinez, Jorge Noronha, Michael Strickland

Published 2014-08-29Version 1

We present an exact solution to the Boltzmann equation which describes a system undergoing boost-invariant longitudinal and azimuthally symmetric radial expansion for arbitrary shear viscosity to entropy density ratio. This new solution is constructed by considering the conformal map between Minkowski space and the direct product of three dimensional de Sitter space with a line. The resulting solution respects SO(3)_q x SO(1,1) x Z_2 symmetry. We compare the exact kinetic solution with exact solutions of the corresponding macroscopic equations with the same symmetry that were obtained from the kinetic theory in ideal and second-order viscous hydrodynamic approximations.