The paper investigates the non-local property of quantum mechanics by using the quantum hydrodynamic analogy (QHA). The role of the quantum potential in generating the non-local dynamics of quantum mechanics is analyzed. The effectiveness of the Bohr-Sommerfeld quantization is investigated in the quantum hydrodynamic equations both in the deterministic as well as stochastic case. The work shows how in presence of noise the non-local properties as well as the quantization of the action are perturbed. The resulting quantum stochastic dynamics much depend by the strength of the interaction: Strongly bounded systems (such as linear ones) lead to a quantum entangled stochastic behavior, while weakly bounded ones may disentangle themselves and to be not able to maintain the quantum superposition of states on large distances acquiring the classical stochastic evolution . The work shows that in the frame of the stochastic QHA approach it is possible to have classical freedom between quantum weakly bounded systems. The stochastic QHA model shows that the wave-function collapse to an eigenstates (deriving by interaction of a quantum microscopic system with the measuring apparatus in a classical environment) can be described by the model itself. Since, on the basis of the Copenhagen interpretation of quantum mechanics the time of the wave function decay to the eigenstate represents the minimum duration time of a measurement, the SQHA shows that the minimum uncertainty principle is compatible with the relativistic postulate about the light speed as the maximum velocity of transmission of interaction. The paper shows that the Lorenz invariance of the quantum potential enforces the hypothesis that superluminal transmission of information is not present in measurements on quantum entangled states.
PACS: 03.65.Ud, 03.67.Mn, 03.65.Ta, 03.75.Gg Keywords: quantum non-locality, superluminal transmission of quantum information, classical freedom, local relativistic causality, EPR paradox, macroscopic quantum decoherence, Bell's inequalities, quantum hydrodynamic analogy