Loophole-free test of local realism via Hardy's violation

[Twodogs]

This is a wide ranging and incisive discussion that prompts a question.
There is a YouTube video in which a physics post-doc uses the Schrodinger equations to calculate the energetics of “a speck of dust in a light breeze”. He determined that such a speck of dust was outside the quantum realm by 20 orders of magnitude.
Is there such a clear demarcation between a quantum realm wherein the low energetics produce uncertainty and non-local phenomenon and a more classical realm wherein events seem to be more clearly determined? I guess that here measurement is still problematic, the keenness of its blade.
Perhaps this is an off topic question or I am simply out of my depth here.

 

[vanhees71]

There is no clear "demarcation" between a quantum and classical realm. The latter is an approximation of the former. Whether or not you can observe quantum properties on macroscopic objects is a question of the ability of preparation as well as accuracy in measuring. A macroscopic object consists of a huge number of microscopic degrees of freedom, which usually you cannot resolve, i.e., you describe the system by some "relevant" macroscopic degrees of freedom. Usually it is very difficult to prevent decoherence concerning these macroscopic degrees of freedom due to their coupling to the many microscopic ones. The decoherence makes the behavior of the macroscopic degrees of freedom classical.

 

[Twodogs]

Thank you. So, while there is no clear demarcation between quantum and classical realms, there is a limit to the ability of an experimentalist to mathematically model more complex systems. There is no clear demarcation, but rather a sharply attenuated segue between realms. As the mass/energy of the system increases, there is a commensurate increase in the certainty of whether things will go one way or another in the work-a-day world. One can reliably set the shopping bag on the counter.