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

Bjorken hydrodynamics applies to the boost invariant regime of heavy ion collisions; Gubser generalized this to nuclei of finite radius. Assuming Gubser's symmetry, the authors solve the Boltzmann equation numerically, and show that hydrodynamics is applicable in a much larger regime than one might naively expect, even when the ratio of the shear viscosity to the entropy density is relatively large.