Constructing Reality: Quantum Theory and Particle Physics, John Marburger, Cambridge U. Press, New York, 2011. $29.00 (287 pp.). ISBN 978-1-107-00483-2
On 28 July 2011, at the age of 70, distinguished physicist John Marburger III passed away, less than two months before the publication of Constructing Reality: Quantum Theory and Particle Physics. Prior to his death, he had served as physics professor at, and president of, Stony Brook University; science adviser to former president George W. Bush; and director of Brookhaven National Laboratory.
Constructing Reality is an ambitious attempt to explain, in a thin volume, special and general relativity, the foundations of quantum mechanics, quantum field theory, and the standard model of particle physics. According to Marburger, the book was written “for my friends who are not physicists, but who are . . . willing to invest some effort to understand it.” He also acknowledges that the book is not likely to be an easy read.
The book’s emphasis on such topics as gauge invariance, the Dirac equation, and the measurement problem in quantum mechanics is unusual for a semipopular exposition. Although the mathematical concepts are presented to aid the reader, when they appear with the text—and not at the end of chapters, as they sometimes do—they’re often awkwardly or partially presented. A physicist would know what the author wants to say and may need no explanation; the nonphysicist is unlikely to be satisfied with arguments that go part way and then break off with phrases like, “It is not difficult (at least for a quantum mechanic) to write down the wave function for two-electron excitations when the nucleus decays.” Nevertheless, if the nonexpert is willing to accept a number of technical assertions without a clear explanation, the book would impart a general flavor of the physics discussed.
The author’s presentation of the standard model is interesting. The explanation of internal symmetries and the important role of symmetry and symmetry-breaking is handled well. No author can escape the tedium of describing the taxonomy of the current particle zoo. It is true that we now have fewer fundamental entities—quarks, leptons, gauge particles, and the Higgs—than there were 50 years ago. But throw in a few internal attributes such as color and muon number, and somehow the burden on the reader does not seem significantly lightened. Nonetheless, Marburger succeeds as well as anyone in making the taxonomy sections readable.
I infer from Constructing Reality that the author has a specific interpretation of quantum mechanics: Copenhagen with a dose of decoherence. Yet he is generous to a fault with those who might hold other views or maintain, as I do, that there are still deep and unresolved issues. His generosity is admirable, but it leads, in places, to vague characterizations of the alternative views. John Bell was very clear about his criticism of the “ ‘and’ of the superposition becoming an ‘or’ in the detection event” in the measurement process. Bell criticized those who thought that there was no problem if only one understood what the wavefunction really is or what detectors really do. He famously qualified the great success of the theory as FAPP (“for all practical purposes”), by which he meant that the orthodox interpretation did not satisfactorily address the foundational questions about measurement. But a reader of Constructing Reality may come away with the notion that Marburger’s disagreement with Bell on the measurement question is not serious. In sidestepping that disagreement and other controversies, Marburger is gracious in motive, but readers should be aware of his strategy.
Constructing Reality should be received as more than an exposition of quantum theory and the standard model of particle physics. It is a personal and passionate statement—a “what I believe” essay—by a distinguished physicist with a lifelong love of physics and a deep commitment to public service. In that context, the book succeeds and is a pleasure to read.
