Paper detail

"Without in Any Way Disturbing the System": Illuminating the Issue of Quantum Nonlocality

In several recent communications (Khrennikov 2019a, b, c, 2020a, b), A. Khrennikov argued for "eliminating the issue of quantum nonlocality" from the analysis of quantum entanglement and quantum phenomena in general. He proposed to differentiate quantum and classical phenomena and entanglement not by their respective nonlocality and locality, as is common, but by the discreteness of quantum phenomena vs. the continuity of classical phenomena, supplemented by Bohr's complementarity in the case of quantum phenomena. As I argue here, however, the question may not be that of "eliminating the issue of quantum nonlocality" but instead of illuminating this issue, a task that can, I also argue, be pursued by relating quantum nonlocality to other key features of quantum phenomena. I suggest that the following features of quantum phenomena and quantum mechanics, distinguishing them from classical phenomena and classical physics--(1) the irreducible role of measuring instruments in defining quantum phenomena; (2) discreteness; (3) complementarity; (4) entanglement; (5) quantum nonlocality; and (6) the irreducibly probabilistic nature of quantum predictions--are all interconnected in defining quantum phenomena and distinguishing them from classical ones, so that it is difficult to give an unconditional priority to any one of them. To argue this case, I consider quantum phenomena and quantum mechanics from a nonrealist or, in terms adopted here, "reality-without-realism" (RWR) perspective. This perspective extends and gives new dimensions to Bohr's view, grounded in his analysis of the irreducible tole of measuring instruments in the constitution of quantum phenomena, with quantum measurement defined by the entanglements between the quantum object under investigation and the instrument used.