New Books of Note

The Harvest of a Century
Discoveries in Modern Physics in 100 Episodes

By Siegmund Brandt, Oxford University Press, 2009, illustrated, 512 pp., $70.00

The Quantum Ten
A Story of Passion, Tragedy, Ambition and Science

By Sheilla Jones, Oxford University Press, 2008, 323 pp., photographs, $24.95

Reviewed by Michael Riordan

Here are two interesting books that have been largely overlooked by the review media— at least those that I pay attention to. Both published by Oxford University Press, they make worthwhile contributions to the literature on 20th century physics, and therefore merit the consideration of Forum members.

Of the two, The Harvest of a Century is more to my liking, a compendium of what the author considers the most significant advances in physics during the past century. Siegmund Brandt is Professor Emeritus of Physics at the University of Siegen. He specialized in experimental particle physics, doing his research at DESY and CERN. From the thoroughness and detailed nature of the book, he has obviously devoted substantial time and effort to studying the history of 20th century physics.

Each of the “episodes,” which begin in 1895 with Röntgen’s discovery of X-rays, are described in four to six pages of text plus period photos and illustrations from the relevant physics literature. Most of them have a good mixture of theory and experiment, giving readers an idea of the interactions that occurred in arriving at a result and interpreting its meaning. More detailed derivations with equations are set off in sidebars, allowing readers so inclined to bypass this material or return to it later. Everything is thoroughly referenced, both to the primary literature where the original papers were published and to some (but not all) of the relevant historical interpretations. Brandt has done his homework.

He emphasizes the experimental side of the discipline, as one might expect, given his professional focus. I, for one, have no problem with this, but others might quibble. (And I was happy to see that no episode on string “theory” was included on his list!) Overall, the treatment is presented at a level such that graduate students in physics can benefit from the book. However, I cannot recommend it to undergraduate students in my courses on the history of 20th century physics, because Brandt assumes a deeper understanding of physics than all but the best of them have.

In any collection like this, there will inevitably be pivotal discoveries and contributions that other scientists feel have been omitted or given short shrift. For instance, the MITSLAC deep-inelastic electron scattering experiments, in which I was involved, are one such lacuna. They gave the first solid evidence for the existence of quarks inside nucleons. Surely these experiments should rate at least as high as the 1973 discovery of weak neutral currents at CERN or the 1979 discovery of gluon jets at DESY, both of which are given entire episodes. Perhaps this omission may be due to Brandt’s pro-European bias; or maybe he is just more familiar with experiments that occurred east of the Atlantic.

Another omission is the revolutionary 1998 discovery of the accelerating universe and its possible interpretation in terms of some variety of dark energy, such as Einstein’s cosmological constant. Perhaps Brandt deliberately overlooked recent astrophysics and cosmology, for the 1991 COBE discovery of fluctuations in the cosmic background radiation is also absent from his list. If so, these are unfortunate omissions.

The Harvest of a Century offers what professional science historians would call an “internalist” account of the history of physics—whose dynamics are determined entirely by the give-andtake of theorists and experimenters following only the internal logic of the field. Almost totally absent from these pages is the role of personal philosophy and individual choice, as well as the impact of external economic, social, and political forces on how the history of modern physics ultimately unfolded.

The opposite is true of The Quantum Ten. In this popular book aimed at a general audience, Sheilla Jones paints a lurid portrait of ten theoretical physicists whose ideas and writings of the 1920s, particularly the core years 1925–1927, led to a successful theory of quantum mechanics—a true scientific revolution in the Kuhnian sense. This is exceedingly well-worn terrain, particularly recently, and thus a difficult arena in which to say anything really new. But Jones succeeds, I believe, by weaving a narrative focused not upon a single physicist (e.g., Bohr or Heisenberg) but on the web of interactions that occurred among an entire group of remarkable iconoclasts. Their activities do not occur in a social or political vacuum but against the turbulent backdrop of Weimar Germany with its dark, looming cloud of intensifying Nazi anti-intellectualism.

The central characters in Jones’s taut drama are (none too surprisingly) “Albert Einstein, the lone wolf; Niels Bohr, the obsessive but gentlemanly father figure; Max Born, the anxious hypochondriac; Werner Heisenberg, the intensely ambitious one; Wolfgang Pauli, the sharp-tongued critic with a dark side; Paul Dirac, the silent Englishman; Erwin Schrödinger, the enthusiastic womanizer; Prince Louis de Broglie, the French aristocrat; Pascual Jordan, the ardent Aryan nationalist…; and Paul Ehrenfest, who was witness to it all” and increasingly depressed that his contributions did not measure up to the others’. Jones in large part mines the work of prominent historians—e.g., Abraham Pais on Einstein and Bohr, David Cassidy on Heisenberg, and Martin Klein on Ehrenfest—but she occasionally delves into original documents, particularly letters between the principals. All of this is fortunately well documented in the references.

But Jones takes greater freedom than most in her interpretations of events, comments and writings, ascribing more to personal and external influences than would most professional historians of science. In some cases, in fact, she gets downright gossipy—as her subtitle adumbrates— especially when it comes to the theorists’ interactions with their wives and lovers. The trysting Schrödinger is a favorite subject in this regard.

The favorite venue is Brussels, where the periodic Solvay Conferences on quantum theory occurred, beginning in 1911 with one on the quantum theory of radiation. An entire chapter and more is devoted to the climactic Fifth Solvay Conference in 1927—to which all ten principals except the Nazi-leaning Jordan were invited— where the interpretation of the new quantum mechanics was vociferously debated and Bohr and Heisenberg’s Copenhagen interpretation supposedly won out. Here Jones leans heavily on the recent Quantum Theory at the Crossroads, by Guido Bacciagaluppi and Antony Valentini (Cambridge, 2009; reviewed in these pages, Spring 2010), which challenges the commonly accepted notion that Bohr and Heisenberg emerged from Brussels victorious. It apparently took a lot longer, claims Jones, ultimately aided by the exhausted resignation of principal opponents de Broglie and Schrödinger.

For both books, I am grateful that Oxford has kept its prices down to levels where ordinary physicists can afford them. Interested but impecunious readers do not have to wait until the local physics library elects to pay a princely sum to put these books on its history of physics shelves. In this regard, The Harvest of a Century will go up on my own bookshelves to serve as a convenient, authoritative reference whenever I need to review in some detail the major advances in 20th century physics.

Michael Riordan is Adjunct Professor of Physics at the University of California, Santa Cruz. Formerly Editor of the History of Physics Newsletter, he now serves as its Book Review Editor. He is author of The Hunting of the Quark and coauthor of Crystal Fire.

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Note Added: This article represents the views of the author, which are not necessarily those of the FHP or APS.