Will we ever quantize the center of mass of macroscopic systems? A case for a Heisenberg cut in quantum mechanics

The concept of quantum particles derives from quantum field theory. Accepting that quantum mechanics is valid all the way implies that not only composite particles (such as protons and neutrons) would be derived from a field theory, but also the center of mass of bodies as heavy as rocks. Despite the fabulous success of quantum mechanics, it is unreasonable to assume the existence of annihilation and creation operators for rocks, and so on. Fortunately, there are strong reasons to doubt that wave mechanics can describe the center of mass of systems at or above the Planck scale, thereby jeopardizing the construction of the corresponding Fock space. As a result, systems with masses exceeding the Planck mass would have their center of mass described through classical mechanics, regardless of being able to harbor macroscopic quantum phenomena as observed in the laboratory. Here, we briefly revisit (i) the arguments for the need for a Heisenberg cut delimitating the boundary between the quantum and classical realms and (ii) the kind of new physics expected at (the uncharted region of) the Heisenberg cut."