Edward Condon’s reflections on the first 60 years of quantum physics
DOI: 10.1063/PT.5.010173
On 2 December 1960 Edward Condon stood in the auditorium of the Natural History Museum in Washington, DC, to address the 1500th meeting of the Philosophical Society of Washington . The topic of his talk was another scientific milestone. Sixty years before, at the 19 October meeting of the German Physical Society in Berlin, Max Planck presented his radiation formula for the first time; quantum mechanics made its public debut.
Condon (shown here) was well qualified to survey the history and progress of quantum physics. After earning his PhD in physics in 1926 at the University of California, Berkeley, he moved to Goettingen to work with Max Born. That same year he published what is perhaps his most famous contribution to physics: His quantum mechanical extension of James Franck’s semiclassical description of vibronic transitions in molecules. In 1929 he and Philip Morse wrote Quantum Mechanics, the first English-language textbook on the topic.
Besides witnessing and participating in the establishment of quantum mechanics, Condon had another early experience that I think prepared him for delving into the subject’s history. Between leaving high school and attending university, he spent three years as a reporter for the Oakland Inquirer and other newspapers.
A reporter’s curiosity and tenacity are evident in Condon’s Washington talk, which appeared in written form in the October 1962 issue of Physics Today. Fascinated by how Lord Rayleigh and other great old physicists of the time struggled to accommodate Planck’s formula within their classical worldviews, he dug into their papers and memoirs and quoted them extensively. Even Planck himself had difficulty, as evidenced from the excerpt that Condon quoted from Planck’s autobiography:
My futile attempts to fit the elementary quantum of action somehow into the classical theory continued for a number of years [actually until 1915] and they cost me a great deal of effort. Many of my colleagues saw in this something bordering on a tragedy. But I feel differently about it, for the thorough enlightenment I thus received was all the more valuable. I now knew for a fact that the elementary quantum of action played a far more significant part in physics than I had originally been inclined to suspect, and this recognition made me see clearly the need for the introduction of totally new methods of analysis and reasoning in the treatment of atomic problems.
In all, Condon devoted five of nine pages of his Physics Today article to his inquiries into the acceptance of quantum mechanics among physicists. That editorial choice, plus his emphasis on his own fields of study, atomic and nuclear physics, left him little room to cover the application of quantum mechanics to condensed matter and field theory. Still, I urge you to read the fascinating article.
And if you want to learn more about Condon, I recommend another Physics Today article. In “Edward Condon and the cold war politics of loyalty,” which appeared in December 2001, historian Jessica Wang discussed the groundless political persecution that Condon faced during his distinguished and productive career.