On the motion of microscopic bodies and observation of position in quantum theory

Abstract

Abstract Newtonian and Scrödinger dynamics can be formulated in a physically meaningful way within the same Hilbert space framework. The resulting unexpected relation between classical and quantum motions goes beyond the results provided by the Ehrenfest theorem. The normal probability distribution and the Born rule turn out to be related. Here a dynamical mechanism responsible for the latter formula is proposed and applied to measurements of macroscopic and microscopic systems. A new meaning of the wave function collapse is proposed. The results are used to explore the classical behavior of macroscopic bodies in quantum theory.