When considering nanocrystalline structures, we are near the microscopic world.

What is the difference between the macro and micro world?

The difference is subtle. For atoms, the macrosocopic world holds, and atoms can be assumed as rigid spheres. In metals this is expressed by a nucleus surrounded by a cloud of electrons.

Inside the atom, the electrons spin the nucleus, in a perpetuum motion. By another hand, in the macroscopic  world, perpetuum motion does not exist (due to friction, for example).

Here, different philosophical approaches of quantum mechanics are discussed, as the Bohmian mechanics, the Bohr interpretation (Kopenhagen) and also the Everett many-worlds hypothesis.

Instead of a “many worlds”, it seems clear that the correct interpretation would be the “many paths”, in agreement with Feynman view.

Experiments have in general confirmed the Bohr interpretation, thus rulling out the Bohmian mechanics

Also by using the Kopenhagen interpretation, the Heisenberg uncertainty principle can be reinterpreted,  showing that time is not absolute.

Also, it will be discussed that as the electron has to be defined using 5 variables (3 dimensions, spin and time) [1], it will be argued that in the microscopic world there are extra dimensions, which we can not observe in the macroscopic world. (In the macro world, we see 4 dimensions: (x,y,z time))  

The concept of Flatland, as exposed in Carl Sagan Cosmos [2] will be used to clarify the different philosophical interpretations of quantum mechanics.