Key points are not available for this paper at this time.
For systems whose classical orbits are chaotic, a set of quantum expectation values Qr is constructed which vanish for all, unlike their classical counterparts Cr which are finite. This behaviour is not paradoxical because Qr and Cr are moments of time correlation functions, which are dominated by the long-time limit where the quantum and classical evolution disagree.
Robbins et al. (Fri,) studied this question.