  It is proved that in non-relativistic quantum mechanics (without spin) the
transition probability may be described in terms of particle paths, every path
having a (positive) probability. This leads to a stochastic hidden variables
theory providing an intuitive picture of particle motion. The change of
velocity at every time has a probability that depends on the potential over a
large region, at a difference with the local action of classical dynamics. Thus
the hidden variables theory is non-local like Bohm's, but not deterministic.

Quantum Physics