System of classical nonlinear oscillators as a coarse-grained quantum   system
  Constrained Hamiltonian dynamics of a quantum system of nonlinear oscillators is used to provide the mathematical formulation of a coarse-grained description of the quantum system. It is seen that the evolution of the coarse-grained system preserves constant and minimal quantum fluctuations of the fundamental observables. This leads to the emergence of the corresponding classical system on a sufficiently large scale. 
Milan Radonji\'c, Slobodan Prvanovi\'c and Nikola Buri\'c
quant-ph nlin.CD