The branches of 20th-century physics that have most captured the public imagination are elementary particle physics and astrophysics. But the area that has undoubtedly had most influence on our daily lives, indeed revolutionised them, is solid-state physics. Where would we be without computers, televisions, mobile telephones, modern communications and modern medical equipment - all products of the electronics industry? At the forefront of this revolution stood John Bardeen, a man who carried the unique distinction of being awarded two Nobel prizes for physics.
Bardeen was a family man, and this biography by Lillian Hoddeson and Vicki Daitch links his scientific life to his liberal upbringing, his education and his family background. It contains portraits of Bardeen as a child, scientist, husband, father and sportsman. It also provides insights into relationships such as those between science and industry and science and government.
Science students will be most interested in the chapters on the discovery of the transistor and of the theory of superconductivity - the contributions that are recognised by his Nobel prizes. There are short clear descriptions of the science involved, but the reader who still finds the science difficult should not be deterred because the accounts also have a human angle. In both cases, the discoveries were the result of a collaboration of three scientists. The interplay between the individuals is as arresting as the science. Bardeen, Walter Brattain and Bill Shockley worked as a team on the discovery of the transistor. But a breach between Shockley and the other two led, ultimately, to Bardeen's departure from Bell Labs, where the discovery was made, to the University of Illinois, where he became professor of electrical engineering and physics and remained until his death.
Collaboration was vital to both discoveries, but the nature of the collaborations was very different. In the case of the transistor, the three scientists were at a similar stage of their careers, Brattain was an experimentalist and the interaction between theory and experiment was vital to the discovery. One of Bardeen's strengths was his ability to design and direct experiments and much of his time was spent in the laboratory with Brattain, especially in the critical days leading to the observation of the transistor effect. The description of the tweaking of the experiments to achieve the desired result is enthralling.
In the second collaboration Bardeen was the senior scientist, Leon Cooper was a research associate and Bob Schrieffer a research student. This did not prevent the three collaborating on equal terms. Although Bardeen knew the literature well and had a clear idea of what the shape of an ultimate theory should be, the younger two were more familiar with the modern mathematical techniques used in field theory. This account shows how these qualities combined to produce the final theory. Cooper used the techniques with which he was familiar to show that in a superconductor the normal state of a metal is unstable against the formation of what are now known as Cooper pairs of electrons. Schrieffer showed how to combine the interacting pairs of electrons into a single wave function for the ground state.
However, the whole edifice rested on the reduction of the complicated strong interactions of the electrons to a simple single weak interaction between quasi-electrons earlier introduced by Bardeen. Bardeen's knowledge and experience were invaluable in the productive period following the discovery of the wave function when the trio calculated an enormous variety of their measurable properties.
Although Bardeen was correct on numerous occasions, he was not always so. His most famous error concerned the existence of the tunnelling of paired electrons between two superconductors. Brian Josephson predicted that such tunnelling would take place and would give rise to a number of observable effects, now known as Josephson effects, while Bardeen denied that they would be observable. The authors describe the dramatic confrontation between Josephson, then a research student at Cambridge University, and the senior scientist and co-discoverer of the basic theory at the Low Temperature Conference in 1962. Experiment proved the student right and the predicted effects are now incorporated in a number of devices.
In his last years, Bardeen developed a macroscopic quantum theory of charged density waves. These are waves of electrons and ions that have a different periodicity from the underlying crystal lattice and occur in materials where electrical conduction takes place along linear chains of molecules. Although Bardeen was sure that his theory was basically correct, it was not accepted by the wider physics community. A picture emerges of a frustrated man estranged from previously close scientific colleagues.
This account of Bardeen's scientific contributions, especially that of the theory of superconductivity, provides a model for conducting research that will benefit those at the start of their careers. He studied the literature to discover what others had accomplished; selected a problem that he believed was tractable; split the problem into more manageable components; identified the physics at the core of these problems; produced simpler models that contained this essential physics; solved these simpler problems; and finally put the solved parts together to produce the whole.
Of course, this prescription requires particular abilities for it to be followed through successfully, but it is a useful ideal. Once Bardeen had focused on what he believed were the key elements, he could be impatient with other points of view. But this rigid belief in his view was no doubt an essential component of his success.
Although Bardeen conducted most of his research in collaboration with others, his oral communication skills were poor, and on social occasions he could be hard going. What was particularly disconcerting was his response when asked a question. There would follow a very long period of silence while he thought about his answer. This could be very embarrassing for those who did not know him well. Eventually one would be rewarded with a considered but brief reply that was worth waiting for. The book abounds with anecdotes arising from this characteristic of his.
Bardeen belied the popular image of mathematicians as unworldly. His skill and keenness for golf are summarised by the chapter heading "Two Nobels are better than one hole-in-one". His political sense to ensure that his younger collaborators were properly rewarded with a Nobel prize for superconductivity is particularly revealing. His practical advice was often sought by colleagues, by industry and by the government. From 1952 to 1980 he was a consultant to the Xerox Corporation and from 1961 to 1974, a member of its board. He also served a term on the Presidential Scientific Advisory Committee, where he advised on the national strategy for research.
The chapter titled "A hand in industry" contains his views on choosing research problems and his advice to others on the conduct of research in industry. Whether or not one agrees with his views, they are always stimulating. He believed that science should serve the public and he laid great stress on possible applications as a stimulus for research.
Nevertheless, the motivation for his own research on superconductivity must have been curiosity and the challenge of an intriguing problem that had defeated the efforts of some of the most distinguished physicists in the world.
As the title implies, the authors use the life of Bardeen to explore the concept of genius. To quote: "The profile (of a genius) which emerges from this biographyI differs greatly from the popular image of a creative genius, but its features are common to the profiles of manyI real geniusesI They include perseverance, motivation, passion, talent, confidence, focus and effective problem solving."
This book is an inspiring and exciting read that can be recommended to layman and scientist alike. It is an affectionate and accurate picture of John Bardeen and portrays science not as a dry isolated pursuit but as an activity of people with the usual prejudices, rivalries, friendships, camaraderie and concern for recognition. Because it quotes widely from Bardeen's notebooks and from his friends, collaborators and colleagues, one gains insight into his thought processes and learns directly of his advice, especially that to the young. It is a model scientific biography.
Gerald Rickayzen is emeritus professor of theoretical physics, University of Kent.
True Genius: The Life and Science of John Bardeen
Author - Lillian Hoddeson and Vicki Daitch
ISBN - 0 309 08408 3
Publisher - Joseph Henry Press
Price - £19.95
Pages - 467