Ergodicity and mixing in quantum theory. II

Abstract

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 $〈x^2〉$ rapidly reach their equilibrium values. The second example makes use of a pair of rotators with nonlinear coupling. The matrix elements of $J_z$, in the energy representation, are pseudorandom in the energy range which is classically chaotic, but obey selection rules in the classically regular energy range.