Quantized chaotic systems are generically characterized by two energy 
scales: the mean level spacing and the bandwidth. 
This implies that with respect to driving such systems have an adiabatic, 
a perturbative and a non-perturbative regimes. A \"strong\" quantal 
non-perturbative response effect is found for systems that are described 
by random matrix theory models.
Is there a similar effect for quantized \"chaotic\" systems ? 
Theoretical arguments cannot exclude the existence of a \"weak\" 
non-perturbative response effect, but detailed numerical investigations 
results in an unexpected degree of semiclassical correspondence.