Quantum mechanics without measurements

TL;DR

This paper proposes a measurement-independent approach to quantum mechanics using consistent microscopic probabilities, which clarifies conceptual issues and can be incorporated into teaching through toy models.

Contribution

It introduces a framework for quantum probabilities that avoids measurement postulates, emphasizing sample spaces and conditional probabilities, enhancing conceptual understanding.

Findings

Probabilities can be calculated without wave function collapse.

Toy models demonstrate the approach's pedagogical utility.

The method clarifies quantum incompatibility and measurement issues.

Abstract

Many of the conceptual problems students have in understanding quantum mechanics arise from the way probabilities are introduced in standard (textbook) quantum theory through the use of measurements. Introducing consistent microscopic probabilities in quantum theory requires setting up appropriate sample spaces taking proper account of quantum incompatibility. When this is done the Schrodinger equation can be used to calculate probabilities independent of whether a system is or is not being measured, and the results usually ascribed to wave function collapse are obtained in a less misleading way through conditional probabilities. Toy models that include measurement apparatus as part of the total quantum system make this approach accessible to students. Some comments are made about teaching this material.