  Generic scalar perturbations on a fixed slowly rotating Kerr-AdS black hole
background exhibit stable trapping, that is, the scalar field remains in a
region between the exterior of the black hole and the AdS boundary for a very
long time, decaying only inverse logarithmically in time. We study this effect
employing fully general simulations that take into account the non-linear
backreaction of the scalar field on the geometry. We find that the stable
trapping of generic perturbations of Kerr-AdS persists at the non-linear level.
Furthermore, the spacetime settles into a time-dependant and non-axisymmetric
black hole which differs from Kerr-AdS. Since our perturbations are generic,
our results indicate that slowly rotating Kerr-AdS black holes are non-linearly
unstable.
