https://doi.org/10.1140/epjh/e2012-20023-1
Bothe’s 1925 heuristic assumption in the dawn of quantum field theory⋆
1 Philipps-Universität Marburg,
Fachbereich Physik,
35032
Marburg,
Germany
2 Fritz-Haber-Institut der Max-Planck
Gesellschaft, 14195
Berlin,
Germany
3 Max-Planck-Institut für
Wissenschaftsgeschichte, 14195
Berlin,
Germany
a e-mail: fick@staff.uni-marburg.de
Received:
7
June
2011
Received in final form:
21
September
2012
Published online:
26
October
2012
In an unpublished manuscript filed at the Archive of the Max-Planck Society in Berlin, Walther Bothe (1891–1957) put, with one heuristic assumption, the spontaneous and induced transitions of light quanta, on an equal footing, probably as early as 1925. In modern terms, he assumed that the probability for the creation of a light quantum in a phase space cell already containing s light quanta is proportional to s + 1 and not, as assumed at that time, proportional to s; that is proportional to the fraction of the total radiation density which belongs to s light quanta. For Bothe, the added +1 somehow replaced the spontaneous decay and allowed him to treat empty phase space cells in a black body as thermodynamically consistent. We describe in some detail Bothe’s route to this heuristic trick. Finally we discuss why, both Bose’s and Bothe’s heuristic assumptions lead to an identical distribution law for light quanta in a black body and thus to Planck’s law and Einstein’s fluctuation formula.
This work emerged from a talk presented by the author at HQ3, The Third International Conference on the History of Quantum Physics organised from by the Max Planck Institute for the History of Science, Berlin. Therefore the mostly technical Sections 2 and 3 do overlap to a large extent with the corresponding sections of “Traditions and Transformations in the History of Quantum Physic” forthcoming in Edition Open Access (http://www.edition-open-access.de)
© EDP Sciences, Springer-Verlag 2012
