|MadSci Network: Physics|
Mechanics or classical physics is somehow regained from quantum theory in the limiting process h -> 0. In fact h is not equal to zero, but very close to it, so we observe behaviour different from what common sense (classical physics) suggests. Deviations from classical physics can be observed at small distances (atomic and subatomic distances) and small energy flows. Macroscopic world is in fact probabalistic and macroscopic objects may admit tunneling, but only the tunneling probability is so small that it will most probably never happen. Macroscopic objects have to tunnel a macroscopic distance, and the amplitude decays exponentially with the distance, so it is de facto zero. So quantum mechanics is the theory the world should be described with. But considering macroscopic phenomena these effects do not often play a prominent role.
I hope my answer helps
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