Simple kinetic-theory tests of dissipative and anisotropic hydrodynamics

We solve the one-dimensional boost-invariant Boltzmann equation in the relaxation time approximation and compare the results with the predictions of dissipative and anisotropic hydrodynamics. We observe that recent formulations of second-order viscous hydrodynamics agree better with the exact solutions than the standard Israel-Stewart approach. In addition, we find that the anisotropic hydrodynamics gives a very good approximation to the exact results provided the appropriate connection between the kinetic and anisotropic hydrodynamics relaxation times is introduced