Ergodicity and mixing in quantum theory. II

The approach proposed in the first part of this paper is illustrated by two examples. The first one involves the Hénon-Heiles model. A small wave packet, initially localized in the classically chaotic region, evolves so that x and x2 rapidly reach their equilibrium values. The second example makes use of a pair of rotators with nonlinear coupling. The matrix elements of Jz, in the energy representation, are pseudorandom in the energy range which is classically chaotic, but obey selection rules in the classically regular energy range.