Macroscopic Body Motion in Terms of Quantum Evolution
  Macroscopic body is considered as a system, consisting of an infinite number of quantum particles. Mechanical motion of the system center of mass in physical space is described, using Feynman's representation of the quantum evolution. It is shown that the center of mass of the system moves accordingly with the minimum action principle if action functional is much higher then Plank's constant. 
A. Yu. Samarin
quant-ph