KS-entropy and logarithmic time scale in quantum mixing systems

We present a calculus of the Kolmogorov-Sinai entropy for quantum systems having a mixing quantum phase space. The method for this estimation is based on the following ingredients: i) the graininess of quantum phase space in virtue of the Uncertainty Principle, ii) a time rescaled KS-entropy that introduces the characteristic time scale as a parameter, and iii) a mixing condition at the (finite) characteristic time scale. The analogy between the structures of the mixing level of the ergodic hierarchy and of its quantum counterpart is shown. Moreover, the logarithmic time scale, characteristic of quantum chaotic systems, is obtained.