Samuel Goudsmit and the 1970 Split of Physical Review


By: Hannah Pell

“Every time you turn around it seems that someone has published a new physics journal,” begins a Special Report in the August 1970 issue Physics Today. The report goes on to list more than 30 new physics and astronomy journals that started in 1968 and had been mentioned in the magazine within the past two years. “Should we, as physicists, welcome these additions to our reading lists? Or should we bemoan the extra contents pages that must be scanned…?” the author asks.

The American Physical Society’s Physical Review journal was no exception to this observation. That same year — exactly fifty years ago now — Physical Review split into four subsidiaries: Physical Review A (atomic, molecular, and optical physics; quantum information), Physical Review B (condensed matter and materials science), Physical Review C (experimental and theoretical nuclear physics), and Physical Review D (theoretical and experimental elementary particle physics, field theory, gravitation, and cosmology). Since its founding in 1893, at a time when there was “no journal in this country entirely devoted to physics, and there was no national society,” Physical Review alone sufficiently encompassed the latest physics research in its monthly volumes that spanned hundreds of pages.

Or did it?

1965: Goudsmit’s Proposed Physical Review Split
“The Physical Review is still growing, to the point where its size already impedes its usefulness to many subscribers,” Goudsmit wrote in a 1965 editorial published in Physical Review Letters, the complementary journal which he had founded in 1958 (and is today the world’s most cited physics journal). Goudsmit — famous for his 1925 joint proposal of the concept of electron-spin — was then editor-in-chief of Physical Review, and he was very outspoken about new directions the journal needed to explore.

Goudsmit’s 1965 proposal outlined five subdivisions of Physical Review as follows: one section would cover “Physics of Atoms and Molecules, Fluids, and Miscellaneous Topics”; a second would cover “Physics of Solids”; a third would cover “Physics of Nuclei”; and the last would cover the “Physics of Elementary Particles and Fields.” Each section was to be published monthly at approximately 300 pages. A member subscription to all sections of the journal was “between $32 and $35 per year” (about $280 today). “The Editors would like to see the five-way split go into effect in 1966,” Goudsmit hoped. But it wouldn’t be until 1970 that Physical Review would officially be published as Physical Review A, B, C and D.

What were some of the reasons that could help explain Goudsmit’s decision?

More and More Physics 

During the 1960s, physics was growing in both size and scope. “Physics research today is on a very much larger scale than it was thirty to forty years ago,” Goudsmit wrote in a 1964 editorial. “In 1965 the Zeitschrift für Physik published 367 papers by 285 authors. In 1963 The Physical Review printed some 1600 papers by about 2500 authors. … On page 486 of this issue of Physical Review Letters, we find a communication which may be described as ‘twenty-seven authors in search of a plot.’” This expansion was also reflected in the increased number of manuscript submissions that Physical Review Letters was seeing. “The number of manuscripts received during the first two and a half months of 1964 was about 30% higher than the average for that period over the preceding four years,” Goudsmit noted. More papers were written by more and more authors, and the influx became too much for one journal alone to publish.

Additionally, physics found its way into to new areas of research. Two years before his 1965 proposal to divide Physical Review, Goudsmit had initially suggested splitting the journal into only two subsections: A, which would cover “the physics of atoms, molecules, and condensed matter,” and B, focused on “physics of the nucleus and elementary particles.” But it didn’t cut it. There was so much new physics happening that even dividing Physical Review in half was not enough to represent the advances in optics, cosmology, field theory, gravitation, and so on. In fact, the editorial team even outlined an analytical subject index that organized the discipline into 65 subtopics. “A drastic modification in the publishing habits of physicists is needed if we do not want our science to disintegrate into a number of minor disciplines, competing for attention,” he wrote in another 1963 editorial.

The topical organization suggested by Goudsmit and the Physical Review editorial team in 1965.

Specializations and Communication Challenges
Because physics was splintering off into many new directions, it was becoming difficult for physicists to keep up with the latest findings outside their own area of expertise. Goudsmit referred to this as a “knowledge explosion,” an incredible amount of scientific information was being discovered and shared at drastically increasing rates. “With the rapid increase of available data, the theories undergo frequent changes or modifications. It has become impossible for a physicist to follow these changes except in his narrow field of specialization.” Although in Goudsmit’s opinion such a knowledge explosion had always existed, what was different then was that increased access to more information forced physicists to realize how much of it was connected to and impactful on their own ongoing research.

An important consequence of increased specialization — especially so in the context of science publishing — was that physicists were having difficulty clearly and effectively communicating their work. “In addition to using unintelligible, twisted sentences, many authors create and use slang expressions known to a few specialists only, and indulge in unnecessary abbreviations. … In fact, many papers give the impression that the author was writing a memorandum to himself merely for the benefit of a close collaborator,” Goudsmit wrote in a 1964 editorial. Although, according to Goudsmit, the “multiplication of journals is, however, not a good solution to the problem of communicating among physicists,” nevertheless this ended up being the best option at the time.

It’s clear that Goudsmit’s decision to divide Physical Review into Physical Review A-D was a consequence of intersecting trends in physics at the time: it’s expansion in size and scope, as well as increased specialization. It was Goudsmit’s hope that dividing the journal into smaller, more focused sections would more accurately encompass the breadth of physics research being done at that time.

The Physical Review Journals Today
In 2019 alone, Physical Review A published 2,490 articles; Physical Review B published 5,040; Physical Review C published 991 articles, and Physical Review D published 3,686 articles. The grand total? 12,207 articles. I won’t even try to guess how many authors (and referees!) were involved in all that work. APS now manages more than fifteen subsidiary journals of Physical Review, with PRX Quantum as the most recent addition focusing on quantum information science and technology research. 

The American Physical Society’s logo celebrating the 50th anniversary of Physical Review A-D.

I wonder what Goudsmit would say about those statistics and the additional journals we have today. The four journals that he played a central role in establishing — in addition to Physical Review Letters, which published 2,680 articles in 2019 with 443,084 total citations — have only continued to grow and maintain their highly prestigious reputation fifty years later. An anniversary offers an opportunity to look back at how things have changed. But in doing so, we’re often reminded that some things have not. Back in 1964, Goudsmit observed the following:
“It is obvious that the growth of physics demands an irreversible increase in specialization. Modern automation may have increased somewhat the amount of physics a researcher can produce, as well as the amount he can use. But the quantity he can read and learn has not changed. We need to modify our publication system to adapt it to the present circumstances.”

Only time will tell how our physics journals will continue to change.

Additional References:

“Box 49, Folder 28, Goudsmit’s Physical Review Letters editorials and announcements, 1958-1974.” Niels Bohr Library & Archives, American Institute of Physics. One Physics Ellipse, College Park, MD 20740.

“Box 45, Folder 097, ‘Consequences of the Knowledge Explosion,’ The Knowledge Explosion, 1966.” Niels Bohr Library & Archives, American Institute of Physics. One Physics Ellipse, College Park, MD 20740.

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