Numerically simulating colliding planar gravitational shock waves in AdS gives rise to rich and interesting dynamics. Wide shocks come to a full stop and expand hydrodynamically, as was previously found by Chesler and Yaffe. High energy collisions (corresponding to thin shocks) pass through each other, after which a plasma forms in the middle, quite akin to heavy-ion collisions. After an initial stage of far-from-equilibrium evolution the pressures become positive and are governed by hydrodynamics within a proper time 1/T, with T the local temperature at that time.
In the end I will discuss recent results where we were able to perform a somewhat similar simulation for boost-invariant central collisions and matched this with recent hydrodynamic and hadronic cascade codes, which enables an interesting comparison with transverse spectra for light particles.