  We investigate the possibility of an Anderson type transition in the quantum
kicked rotor with a smooth potential due to dynamical localization of the
wavefunctions. Our results show the typical characteristics of a critical
behavior i.e multifractal eigenfunctions and a scale-invariant level-statistics
at a critical kicking strength which classically corresponds to a mixed regime.
This indicates the existence of a localization to delocalization transition in
the quantum kicked rotor.
  Our study also reveals the possibility of other type of transitions in the
quantum kicked rotor, with a kicking strength well within strongly chaotic
regime. These transitions, driven by the breaking of exact symmetries e.g.
time-reversal and parity, are similar to weak-localization transitions in
disordered metals.
