Quantum fluctuations, particles and entanglement: a discussion towards the solution of the quantum measurement problems (2111.14723v2)

Abstract: The quantum measurement problems are revisited from a new perspective. One of the main ideas of this work is that the basic entities of our world are various types of particles, elementary or composite. It follows that each elementary process, hence each measurement process at its core, is a spacetime, pointlike, event. Another key idea is that, when a microsystem $\psi$ gets into contact with the experimental device, factorization of $\psi$ rapidly fails and entangled mixed states appear. The wave functions for the microsystem-apparatus coupled systems for different measurement outcomes then lack overlapping spacetime support. It means that the aftermath of each measurement is a single term in the sum: a "wave-function collapse". Our discussion leading to a diagonal density matrix, $\rho= {\rm diag} ( |c_1|^2, \ldots, |c_n|^2, \ldots )$ shows how the information encoded in the wave function $|\psi\rangle = \sum_n c_n | n \rangle$ gets transcribed, via entanglement with the experimental device and environment, into the relative frequencies ${\cal P}_n = |c_n|^2$ for various experimental results $F=f_n$. These results represent new, significant steps towards filling in the logical gaps in the standard interpretation based on Born's rule, and replacing it with a more natural one. Accepting objective reality of quantum fluctuations, independent of any experiments, and independently of human presence, one renounces the idea that in a fundamental, complete theory of Nature the result of each single experiment must necessarily be predictable. A few well-known puzzles such as the Schr\"odinger cat conundrum and the EPR paradox are briefly reviewed: they can all be naturally explained away.