Solving the measurement problem within standard quantum theory

TL;DR

This paper demonstrates that the quantum measurement problem can be resolved within standard quantum theory by analyzing nonlocality experiments, showing the measurement state is a correlation superposition rather than a paradoxical superposition, thus clarifying the nature of definite outcomes.

Contribution

It provides a novel optical-path analysis that explains measurement outcomes without relying on reduced density operators, addressing longstanding criticisms and resolving the measurement problem.

Findings

Measurement state is a superposition of correlations, not paradoxical superpositions.

Nonlocality experiments support the interpretation of measurement as correlation.

Optical-path analysis predicts experimental results without reduced density operators.

Abstract

A misunderstanding of entangled states has spawned decades of concern about quantum measurements and a plethora of quantum interpretations. The "measurement state" or "Schrodinger's cat state" of a superposed quantum system and its detector is nonlocally entangled, suggesting that we turn to nonlocality experiments for insight into measurements. By studying the full range of superposition phases, these experiments show precisely what the measurement state does and does not superpose. These experiments reveal that the measurement state is not, as had been supposed, a paradoxical superposition of detector states. It is instead a nonparadoxical superposition of two correlations between detector states and system states. In this way, the experimental results resolve the problem of definite outcomes ("Schrodinger's cat"), leading to a resolution of the measurement problem. However, this argument does not yet resolve the measurement problem because it is based on the results of experiments, while measurement is a theoretical problem: How can standard quantum theory explain the definite outcomes seen experimentally? Thus, we summarize the nonlocality experiments' supporting theory, which rigorously predicts the experimental results directly from optical paths. Several previous theoretical analyses of the measurement problem have relied on the reduced density operators derived from the measurement state, but these solutions have been rejected due to criticism of reduced density operators. Because it avoids reduced density operators, the optical-path analysis is immune to such criticism.