Editing Semiclassical physics (section)

== History ==
[[Max Planck]] was the first to introduce the idea of quanta of energy in 1900 while studying [[black-body radiation]]. In 1906, he was also the first to write that quantum theory should replicate classical mechanics at some limit, particularly if the [[Planck constant]] ''h'' were infinitesimal.<ref name=":0">{{Cite journal |last=Liboff |first=Richard L. |date=1984-02-01 |title=The correspondence principle revisited |url=https://pubs.aip.org/physicstoday/article/37/2/50/402950/The-correspondence-principle-revisitedThe-usual |journal=Physics Today |language=en |volume=37 |issue=2 |pages=50–55 |doi=10.1063/1.2916084 |issn=0031-9228|url-access=subscription }}</ref><ref name=":1">{{Cite book |last=Planck |first=Max |title=Vorlesungen über die Theorie der Warmestrahlung |publisher=Verlag von Johann Ambrosius Barth |year=1906 |publication-place=Leipzig}}</ref>  With this idea he showed that [[Planck's law]] for thermal radiation leads to the [[Rayleigh–Jeans law]], the classical prediction (valid for large [[wavelength]]).<ref name=":0" /><ref name=":1" />