By Gerald E Brown and Chang-Hwan Lee (eds), World Scientific. Hardback ISBN 9789812566096 £56 ($98). Paperback ISBN 9789812566102 £22 ($38).
This book is the result of a request that Hans Bethe made at the age of 97 to his long-term collaborator Gerry Brown to explain “his physics” to the world. This is no easy feat considering that the published scientific papers, books and reports span the best part of eight decades, and include some of the most important contributions to 20th-century physics. Brown and Lee have risen to the challenge and produced a book of which Bethe himself would be proud. It even goes beyond Bethe’s initial request to explain his physics and provides a portrait of the great man in all aspects of his life, which Brown and Lee have accomplished by enlisting the help of experts, collaborators and friends.
In part one of this four-part book, we catch a personal glimpse of the man and his science through the eyes of close collaborators and friends. Brown summarizes and evaluates Bethe’s long career as a teacher and researcher, starting with a brief history of his early years in Germany and England, with a short stay in Italy. He describes how Bethe developed mathematical rigor working with Arnold Sommerfeld and gained physical intuition from Enrico Fermi.
However, Bethe found that the British had a much healthier attitude towards life than the Germans, and with the rise of Adolf Hitler and the new laws he could not hold a university position as two of his grandparents were Jewish. So in 1933 he moved to Manchester University where he was reunited with his old friend Rudi Peierls. Bethe regarded 1933–34 as his most productive time, although he had already published the famous “Bethe ansatz”. Brown ends his article by describing his own long collaborative research with Bethe in astrophysics.
Bethe’s own article, “My life in astrophysics”, highlights his strengths and the application of nuclear physics in stellar energy production, for which he won the Nobel prize in 1967. The article describes in detail the whole Nobel experience; his enjoyment is obvious. He concludes by describing his return to astrophysics after retiring from Cornell University.
“Three weeks with Hans Bethe” by Chris Adami is a transcript of conversations with Bethe and Brown over a three-week period at the Kellogg Radiation Laboratory at Caltech. Here Adami provides a unique insight into the mind of Bethe, his thoughts on science, people and politics. Adami quizzed Bethe on almost every aspect of his life, keeping a record of each day’s discussion, a real Bridget Jones’s Diary of physics. Here we learn that Bethe was an expert on shock waves and explosions, which he had ample opportunity to develop during his time at Los Alamos, and Adami was sometimes met with silence if the questioning came too close to classified work.
Bethe’s commitment to nuclear energy is highlighted in the short article by Jeremy Bernstein, who had written a piece about Bethe for the New Yorker, highlighting his enthusiasm for nuclear energy. At the time, Bethe debated the nuclear option with Barry Commoner, a committed environmentalist and the magazine’s energy guru. Such debates are again increasingly relevant, but without a Bethe, explaining the nuclear option is more difficult. Part one concludes with a well crafted piece by Ed Salpeter who interacted with Bethe over a 60 year period.
Kurt Gottfried introduces part two, followed by Silvan Schweber who gives an account of Bethe’s education, swift rise to international prominence and immense impact on American physics. The other four papers in this section deal with distinct aspects of his research. Salpeter and the late John Bahcall expand on Bethe’s work on energy production in stars, nuclear astrophysics and neutrino physics. Bethe wrote an important and influential paper in 1986 on the missing solar neutrinos, explaining the Mikheyev–Smirnov–Wolfenstein effect. This is the best explanation of matter effects on neutrino oscillations that I have come across. Freeman Dyson traces Bethe’s influence on the development of quantum electrodynamics and the story of how he solved the Lamb shift problem, claiming that “Hans Bethe was the supreme problem solver of the past century”. John Negele describes Bethe’s work on the theory of nuclear matter and the post-war contribution he made to the nuclear many-body problem. Brown concludes this section by providing an intimate look at his remarkable collaboration with Bethe on supernovae and mergers between neutron stars and black holes as possible sources of gravitational waves.
Part three contains papers by Chen Ning Yang and Mo-Lin Ge on the impact of what Yang had termed the “Bethe ansatz”, which extended to many systems beyond the 1D problem in quantum mechanics that Bethe originally considered. David Mermin and Neil Ashcroft describe how influential Bethe was in solid-state physics. However, although he played a major role in developing the quantum theory of solids, he realized by 1933 that his real interest was in nuclear physics. Jeremy Holt and Brown provide a historical summary of nuclear physics where they put Bethe’s major contributions into context. Sometimes in physics the exact details of discovery are not well documented, but not in this case I am pleased to say. This section ends with the paper “And don’t forget the black holes”, which Bethe co-authored with Brown and Chang-Hwan Lee shortly before his death.
The last part of the book concludes with a set of papers discussing Bethe’s contribution to science policy at all levels. Sydney Dell recounts the various ways in which Bethe’s integrity, together with his incredible scientific knowledge, made him an admirable adviser to policy makers. Bethe’s panel helped shape the Limited Test Ban Treaty of 1963. He was deeply concerned with new threats posed by nuclear weapons and was deeply involved in all aspects of the global-energy problem. The article by Boris Ioffe on “Hans Bethe and the global energy problem” outlines Bethe’s commitment to the peaceful use of nuclear energy. He also advocated strategies to police and limit the amount of weapons-grade material, a very real threat in today’s global political scene. The book concludes with obituaries by Richard Garwin, Frank von Hippel and Gottfried.
This book does an admirable task in drawing a portrait of a great scientist and a great man. Bethe’s power, in my experience, was that he could always easily get to the heart of a problem in any field and solve it in the most economical way, and this comes through clearly. The book is a “must read” for every researcher and teacher of science.
