We show that the invariance of entropic distances under Liouville dynamics yields classical analogues of information-related, quantum mechanical impossible operations. By recourse to Fisher's information measure, we also establish a connection between such classically forbidden operations and statistical estimation theory.
We consider the possibility of performing, in the context of Liouville dynamics, certain information related, universal processes on classical ensemble probability distributions. This problem constitutes a classical counterpart of the study of universal processes in quantum mechanics, which is nowadays the focus of intensive research. The time independence of appropriate entropic distances between time dependent solutions of Liouville equation allows to establish the impossibility of some of the alluded processes. The present problem is also considered within the framework of discrete classical dynamics.
We clarify certain confusions in the literature of the density operator in quantum mechanics, and demonstrate that the quantum Liouville theorem has the same form in both the Schrodinger and the Heisenberg pictures.Our starting point is to treat the density operator as an observable which has its specific time dependence in each of the two pictures.It is further shown that such a formulation will provide the exact correspondence between classical and quantum statistical mechanics with the Liouville theorem being interpreted as a conservation law, which is derivable from the equation of motion only in the quantum case.