# Planck's radiation law, the light quantum, and the prehistory of indistinguishability in the teaching of quantum mechanics

## TL;DR

This paper explores the historical development of Planck's radiation law, the concept of light quanta, and the origins of indistinguishability in quantum mechanics, proposing improvements for teaching these foundational ideas.

## Contribution

It provides a simplified historical account linking Planck's law, light quanta, and indistinguishability, suggesting enhancements in quantum mechanics education.

## Key findings

- Clarifies the historical debate on Planck's quantization
- Highlights the role of indistinguishability in quantum theory
- Proposes integrating historical insights into teaching practices

## Abstract

Planck's law for black-body radiation marks the origin of quantum theory and is discussed in all introductory (or advanced) courses on this subject. However, the question whether Planck really implied quantisation is debated among historians of physics. We present a simplified account of this debate which also sheds light on the issue of indistinguishability and Einstein's light quantum hypothesis. We suggest that the teaching of quantum mechanics could benefit from including this material beyond the question of historical accuracy.