  We study the evolution of quantum fluctuations in the Glasma created
immediately after the collision of heavy nuclei. It is shown how the presence
of instabilities leads to an enhancement of non-linear interactions among
initially small fluctuations. The non-linear dynamics leads to an enhanced
growth of fluctuations in a large momentum region exceeding by far the
originally unstable band. We investigate the dependence on the coupling
constant at weak coupling using classical statistical lattice simulations for
SU(2) gauge theory and show how these non-linearities can be analytically
understood within the framework of two-particle irreducible (2PI) effective
action techniques. The dependence on the coupling constant is only logarithmic
in accordance with analytic expectations. Concerning the isotropization of bulk
quantities, our results indicate that the system exhibits an order-one
anisotropy on parametrically large time scales. Despite this fact, we find that
gauge invariant pressure correlation functions seem to exhibit a power law
behavior characteristic for wave turbulence.
