Apparent randomness in quantum dynamics.

Abstract

We show how bounded quantum systems in the presence of time-periodic fields can mimic random behavior in spite of their almost periodic character. We calculate the distribution of values taken by observables in the course of time, and demonstrate how they become asymptotically Gaussian in the large-N limit but with constant variance and a posteriori, \ensuremath{\delta}-correlated noise. Thus, unlike a priori processes, the quantum dynamics of bounded systems remains nondiffusive while appearing to be random.