Did Herbert Fr\"ohlich predict or postdict the isotope effect in superconductors?

TL;DR

This paper critically examines whether Herbert Fröhlich truly predicted the isotope effect in superconductors in 1950, analyzing the historical facts and interpretations surrounding his work.

Contribution

The paper clarifies the historical record and debates whether Fröhlich's work was a genuine prediction or a postdiction regarding the isotope effect.

Findings

Fröhlich's role in predicting the isotope effect is ambiguous.

The interpretation of Fröhlich's work depends on the definition of 'shortly'.

Historical analysis challenges the common belief about Fröhlich's prediction.

Abstract

Herbert Fr\"ohlich is generally credited with having predicted the fundamental role of electron-phonon interactions in superconductivity in 1950, and in particular the isotope effect, without any experimental input. Here we examine the facts on which this belief is based and point out that whether or not the generally accepted view is true depends on the meaning of the word {\it shortly}.