  Considering a kicked rotor coupled to a model heat bath both the classical
and quantum entropy productions are calculated exactly. Starting with an
initial wave packet, the von Neuman entropy as a function of time is determined
from the reduced density matrix while the Liouville evolution of the
corresponding Husimi distribution provides us with the classical entropy. It is
found that both these entropies agree reasonably satisfying the same asymptotic
growth law and more importantly both are proportional to the classical
Liapounov exponent.
