Following the procedure introduced by Israel and Stewart, we expand the
entropy current up to the third order in the shear stress tensor
παβ and derive a novel third-order evolution equation for
παβ. This equation is solved for the one-dimensional Bjorken
boost-invariant expansion. The scaling solutions for various values of the
shear viscosity to the entropy density ratio η/s are shown to be in very
good agreement with those obtained from kinetic transport calculations. For the
pressure isotropy starting with 1 at τ0=0.4fm/c, the third-order
corrections to Israel-Stewart theory are approximately 10\% for η/s=0.2
and more than a factor of 2 for η/s=3. We also estimate all higher-order
corrections to Israel-Stewart theory and demonstrate their importance in
describing highly viscous matters.Comment: Version published in Phys.Rev.C. 5 pages, 1 figur