"Evaluations" of Observables Versus Measurements in Quantum Theory

TL;DR

This paper clarifies the conceptual distinction between direct measurements and evaluations of observables in quantum physics, demonstrating that evaluations cannot be equated with measurements due to fundamental contradictions.

Contribution

It provides a rigorous analysis distinguishing evaluations from measurements in quantum theory, clarifying their conceptual status and implications.

Findings

Evaluations are not equivalent to measurements in quantum physics.

Identifying evaluations with measurements leads to contradictions.

The paper establishes the conceptual role of evaluations in quantum theory.

Abstract

In Quantum Physics there are circumstances where the direct measurement of particular observables encounters diffculties; in some of these cases, however, its value can be evaluated, i.e. it can be inferred by measuring another observable characterized by perfect correlation with the observable of interest. Though an evaluation is often interpreted as a measurement of the evaluated observable, we prove that the two concepts cannot be identified in Quantum Physics, because the identifcation yields contradictions. Then, we establish the conceptual status of evaluations in Quantum Theory and the role can be ascribed to them.