The quantum mechanics needs the principle of wave function collapse, but this principle should not be misunderstood

TL;DR

The paper argues that wave function collapse is a necessary aspect of quantum mechanics, clarifies misconceptions about its nature, and critiques interpretations that attempt to avoid it, emphasizing its role in reconciling quantum and classical worlds.

Contribution

It provides theoretical proofs that the collapse postulate is essential in quantum mechanics and clarifies misconceptions about collapse at a distance, especially in relativistic contexts.

Findings

Collapse is necessary for quantum mechanics consistency.

Interpretations avoiding collapse often make incompatible assumptions.

Collapse at a distance leads to contradictions in entanglement scenarios.

Abstract

The postulate of the collapse of the wave function stands between the microscopic, quantum world, and the macroscopic world. Because of this intermediate position, the collapse process cannot be examined with the formalism of the quantum mechanics (QM), neither with that of classical mechanics. This fact makes some physicists to propose interpretations of QM, which avoid this postulate. However, the common procedure used in that, is making assumptions incompatible with the QM formalism. The present work discusses the most popular interpretations. It is shown that because of such assumptions those interpretations fail, i.e. predict for some experiments results which differ from the QM predictions. Despite of that, special attention is called to a proposal of S. Gao, the only one which addresses and tries to solve an obvious and major contradiction. A couple of theorems are proved for showing that the collapse postulate is necessary in the QM. Although nonexplainable with the quantum formalism this postulate cannot be denied, otherwise one comes to conclusions which disagree with the QM. It is also proved here that the idea of collapse at a distance is problematic especially in relativistic cases, and is a misunderstanding. Namely, in an entanglement of two quantum systems, assuming that the measurement of one of the systems (accompanied by collapse of that system on one of its states) collapses the other system too without the second system being measured, leads to a contradiction.