Difficulties with Collapse Interpretations of Quantum Mechanics

TL;DR

This paper critically examines the concept of wave function collapse in quantum mechanics, highlighting theoretical and experimental challenges that undermine collapse interpretations and suggesting they are unlikely to be viable.

Contribution

It provides a comprehensive review of collapse theories, demonstrating their theoretical inconsistencies and lack of experimental support, and argues against their feasibility within current quantum frameworks.

Findings

No experimental evidence supports collapse theories.

Collapse models require nonlinear, non-local, and instantaneous processes.

Current quantum mechanics cannot accommodate a universal collapse mechanism.

Abstract

Quantum mechanics gives many versions of reality but we perceive only one. One potential explanation for this, the one considered here, is that the wave function collapses down to just one version. The experimental situation is briefly reviewed, with no evidence found for collapse. The theoretical position is also reviewed and found wanting. Collapse-by-observation schemes are logically untenable. A mathematical theory of collapse must be nonlinear, a significant departure from current quantum theory. In addition, the primary candidate theory, the GRW-Pearle model, requires instantaneous, non-local transmission of information. It also requires transmission of information across versions of reality, which is forbidden in current quantum mechanics. And there is no apparent physical quantity, such as particle number, that can provide the mechanism for collapse in all cases. Further, these aspects, which are in disagreement with current theory, seem to be necessary for any mathematical theory of collapse. The conclusion is that the outlook for mathematical collapse schemes is not encouraging.