Reply to the Comment by Casati et al. on "Field theory of the quantum kicked rotor" [Phys. Rev. Lett. 77, 4536 (1996)]

In a recent comment [cond-mat/9703106] Casati, Izrailev and Sokolov claim that our analysis of the quantum kicked rotor [Phys. Rev. Lett. 77, 4536 (1996), chao-dyn/9609014] seems to miss an important aspect, viz. the difference in behavior between rational and irrational values of the parameter T = tau/4pi (tau being the time between kicks). The fact of the matter is that our approach does depend very sensitively on the number theoretical properties of T. In our reply we show how the 'degree of rationality' is related to the topological aspects of our theory and point out the phenomenological consequences of this connection.