by John Gribbin
This, maybe, explains why Feynman never got too upset that credit for his greatest discovery had to be shared. It was his own fault, and nobody else’s, that he hadn’t looked up the experimental data before going to Brazil, spotted the error and published his theory immediately. He could live with that; and, besides, he still knew that he had worked it all out by himself, even if some other people were almost as quick off the mark as he had been.
Maybe the theory of the weak interaction might, under other circumstances, have won somebody a Nobel Prize; the work is certainly of at least as high a standard as many of the achievements which have been honoured in that way. But there’s a snag – one of the rules that is never broken is that the prize for a particular piece of work cannot be shared by more than three people. It is a ridiculous and arbitrary rule, but it means that the possibility of giving the award jointly to Feynman, Gell-Mann, Marshak and Sudarshan was never even discussed.
The theory of superfluidity and the theory of the weak interaction were Feynman’s two great contributions to physics in the 1950s, and either of them would have been enough to establish the credentials of any ordinary physicist in the top rank of the profession, and provide him or her with sufficient kudos to last a lifetime. They pale in the Feynman legend only alongside the glorious brilliance of QED itself. And yet, alongside these two epic pieces of work, his domestic troubles, his visits to Las Vegas and other interesting places, his sometimes exotic social life and then his meeting and marriage with Gweneth,* in the 1950s Feynman also found time to make a few other contributions, by way of relaxation, in different fields of science and engineering.
In the mid-1950s, as if he didn’t already have enough on his plate, Feynman got involved with the development of masers (forerunners to lasers) through the presence at Caltech of Robert Hellwarth, a maser specialist. In collaboration with a research student, Frank Vernon, they developed a simple way of calculating problems involving masers and lasers, using a new kind of diagram as an easy way for engineers dealing with practical problems to come to grips with quantum mechanics; the work became one of Feynman’s most cited contributions to physics,14 and the chances are that the person who designed the laser in your CD player used the FVH technique in that work. Hellwarth moved on to work for the Hughes Aircraft Company, and through this connection Feynman began to give a series of lectures at Hughes, talking on any subject he liked. The lectures took place every week, on Wednesday, when Feynman was in California, and he enjoyed them so much that the tradition continued for the best part of 30 years.
Feynman was also interested in the new developments in molecular biology, the study of DNA, which carries the genetic message of life. One of the reasons why he decided to stay at Caltech, as we have seen, was the presence of biological researchers such as Max Delbrück on the campus, and the opportunity to keep bang up to date with developments in this field. In the second half of the 1950s, Feynman arranged with Delbrück and a younger biologist, Robert Edgar, that he would hang out in their department from time to time, acting like a graduate student in biology, being taught how to handle the biological material and given a small project to work on. This proved so interesting that when he became eligible for another sabbatical year, in 1959–60, Feynman spent it working on DNA studies at Caltech with Matt Meselson. He learned a great deal, without making any major contribution, and had an opportunity to get acquainted with many of the top researchers in the field. But the most pleasing aspect of his year in biology came through his duties as a teaching assistant. He taught first-year biology students, who had no idea who Dick Feynman was, the basic practical techniques of their trade, plus mathematics and statistics. At the end of the year, the students ranked him as the best teaching assistant they had encountered. ‘I got a tremendous boost by obtaining the best score of all teaching assistants; even in biology, not my field, I could explain things clearly, and I was rather proud of it.’15
Feynman was, indeed, about to come into his prime as a great explainer. But his most memorable contribution to science during that sabbatical year in biology came from a one-off talk that he gave, at the end of December 1959, to the annual meeting of the American Physical Society, which happened to be held in Caltech that year. The talk was titled ‘There’s Plenty of Room at the Bottom’,16 and it is hailed today as the first clear statement of the possibilities of nanotechnology – engineering on the scale of atoms and molecules.17
In the talk, Feynman threw out two challenges, offering a $1,000 prize to the first person to solve each of them. One was to build a working electric motor that would fit inside a cube 1⁄64 inches on each side. To his surprise (and consternation – he had made no arrangements to fund the prize, and paid up out of his own pocket) this was achieved by a local engineer, William McLellan, by November 1960. McLellan took his equipment along to show Feynman; it was in a large wooden box, and he has told how Feynman’s eyes seemed to glaze over at the sight. Then, McLellan opened the box and took out a microscope with which to view his tiny motor. ‘Uh-oh’, Feynman said.18
The other prize was for anyone who could find a way to write small enough to get the entire Encyclopaedia Britannica on the head of a pin, a reduction of 25,000 times from its standard print size. On that scale, ‘all of the information which mankind has ever recorded in books can be carried around in a pamphlet in your hand’,19 a pamphlet equivalent to 35 pages of the printed Encylopaedia Britannica. This prize was claimed in 1985, by Tom Newman, a graduate student at Stanford University. He wrote out the first page of Charles Dickens’ A Tale of Two Cities at the required scale, on the head of a pin, using a beam of electrons. The main problem he had before he could claim the prize was finding the text (using an electron microscope) after he had written it – the head of the pin was a huge empty space compared with the page of text inscribed on it. Ten years later, in 1995, scientists at the Los Alamos National Laboratory were literally copying the texts of entire books on the sides (not the heads) of steel pins measuring 25 by two millimetres, each capable of storing two Gigabytes of data in a permanent, readable form. What seemed like a wild flight of fancy at the end of 1959 became practical reality some 35 years later, with applications for data storage and retrieval anywhere that large amounts of information have to be stored in read-only form.
In the next century, such databases as the Library of Congress and the British Library really may be based on maintaining a collection of a few steel pins from which copies of any book ever written can be printed up on demand. All this was clearly foreseen by Feynman, and presented to the astonished gathering of physicists in 1959, like a magician pulling a rabbit out of a hat, by someone taking time off from being the best teaching assistant in the biology department at Caltech. Having finished his work on superfluidity and on the weak interaction, and having completed his biological sabbatical, at the beginning of the 1960s Feynman was without a major research problem to pursue over the next few years (except for his unpublished private investigations of gravitational theory), but had settled at last into a happy marriage. He was ideally placed to make the leap from being the best teacher at Caltech to being the best physics teacher in the world, reaching a wider audience than ever before (and pulling a few more rabbits out of the hat as he did so) with the books that, as Schwinger might have put it, brought Feynman’s way of thinking about physics to the masses.
Notes
1. See Most of the Good Stuff.
2. Surely You’re Joking.
3. Told by Feynman to Mehra.
4. Surely You’re Joking.
5. See Joan Feynman’s contribution to No Ordinary Genius.
6. Surely You’re Joking.
7. Willy Fowler, conversation with JG, early 1970s.
8. Ralph Leighton, interview with JG, April 1995. See also Surely You’re Joking.
9. Proceedings of the International Conference on the Theory of Gravitation, Gauthier-Villars, Paris, 1964.
10. Surely You’re Joking.
11. Mehra. Th
e comment that ‘no one else knew’ refers, of course, to how Feynman felt at the time he made his discovery; it was only later, as we discuss in the main text, that he found out that Gell-Mann, and Sudarshan and Marshak, had got there independently, and that didn’t diminish his euphoria one bit.
12. See Mehra.
13. Surely You’re Joking.
14. Mehra.
15. Mehra.
16. It was published in the February 1960 issue of Engineering and Science, see also No Ordinary Genius.
17. See, for example, Ed Regis, Nano! (Bantam Press, London, 1995).
18. Told by McLellan to Gleick.
19. Feynman, note 16.
* The social life and physics entwine delightfully here, since the reason Feynman was in Switzerland when he met Gweneth was that in 1958 the ‘Rochester’ conference had become peripatetic, uprooting itself and settling in Switzerland for a season.
9 Fame and (some) fortune
As Feynman entered the 1960s, he was secure in both his personal and his professional lives. He was about to be married, he had made the decision never to leave Caltech, and in the autumn of 1959 he had been appointed Richard Chace Tolman Professor of Theoretical Physics, bringing his salary in 1960 above the $20,000 mark and making him the highest paid member of the faculty. But he was as yet a well-known figure only in the world of physics.1 By now in his early forties, even Feynman himself may have suspected that his great achievements in theoretical physics all lay behind him, although he continued to beaver away on his investigations of gravity, trying to find a way to a quantum mechanical description of gravitational phenomena, linking gravity and quantum physics in the way that Maxwell had linked electricity and magnetism. He never succeeded in that objective. But his career was about to take an unexpected turn that would lead to much more fame than Feynman can ever have anticipated; and as we shall see in Chapter 10, by the end of the decade, even in his fifties Feynman would make one last great contribution to theoretical physics.
In spite of its success as a world centre for research, at the beginning of the 1960s physics at Caltech had a problem. Undergraduates were still being taught courses along the lines laid down in the 1940s, learning a great deal of classical physics in their first two years, but only coming on to the excitement of topics like relativity, quantum theory and atomic physics in their third year of study, by which time their brains had been numbed by the dullness of the first two years.
The person who started the move to drag physics teaching at Caltech into the second half of the 20th century was Matthew Sands, the physicist friend of Feynman who had acted as Gweneth’s sponsor when she had applied for her visa. Sands persuaded an initially reluctant Robert Bacher, head of the physics division, that something needed to be done, and Bacher obtained funds from the Ford Foundation towards the cost of a complete overhaul of the introductory physics course. Bacher brought Robert Leighton, a more traditionally minded physicist, on board to act as a counterbalance to some of Sands’ more extreme enthusiasms, while the experimenter Victor Neher set to work devising the practical side of the lab work for the new course.
The collaboration between Sands and Leighton did not proceed smoothly in the early months of 1960. Leighton wanted a traditional course; Sands, constantly seeking advice from Feynman, wanted something new and fresh. ‘We could not seem to converge on a solution’, Sands later told Mehra; but ‘one day I had the brilliant inspiration of saying, “Look, why don’t we get Feynman to give the lectures and let him make the final decision on the contents?”’
No other great physicist had ever taught freshman physics (at least, not after achieving the status of being a great physicist), and Feynman was intrigued by the challenge, and the opportunity to set out his way of thinking about the world for a wider audience. Leighton was wary, but carried along by the enthusiasm of Sands and Neher. So it was that Feynman began what was supposed to be a one-year series of lectures on introductory physics in the autumn of 1961. In the end, the course spanned two academic years, from September 1961 to May 1963. The deal was that he would give the course once, and once only.
Aware that this was going to be a special event, from the outset Caltech took care to ensure that the lectures were preserved for posterity. Everything was recorded, and Leighton and Sands took on the job of converting the recordings (a total of more than a million spoken words)2 first into written notes and then into book form (a task which Leighton estimated involved from ten to twenty hours of work per lecture).3 Feynman gave two lectures a week, and devoted himself full time to their preparation and presentation, planning how to structure his presentation and get the story across. But although he thought everything through in advance, he had no formal notes when it came time to talk, just a single sheet of paper with key words written on it to remind him of the flow of the presentation.
What made Feynman a great teacher, according to David Goodstein,4 was that ‘for Feynman, the lecture hall was a theater, and the lecturer a performer, responsible for providing drama and fireworks as well as facts and figures. This was true regardless of his audience, whether he was talking to undergraduates or graduate students, to his colleagues or the general public.’ Goodstein stresses the amount of preparation that went into all of Feynman’s lectures down the years, so that although he was certainly capable of talking spontaneously on almost any aspect of physics, and did indeed include off-the-cuff remarks in his lectures, the whole structure of the talk (including some of the apparent ad libs and joking asides) was carefully planned in advance. ‘He didn’t need very many notes – I know from his lecture notes, that he didn’t need very many notes to remind himself of what he wanted to say. But he knew in great detail what he wanted to say.’5
Feynman’s famous undergraduate lectures lived up to this ideal; they were like shows, entertainments with a beginning, a middle and an end. Each lecture was self-contained, but ended with a summary of key points that the students were supposed to carry away with them for future reference. Anybody who wants to can now get a flavour of what it was like to be present at these lectures, because in 1995 six of them were presented in a package combining a book and copies of the original audio recordings of Feynman giving the lectures.6 There is no better way to get a feel for the physics of atoms and molecules, quantum theory, energy, gravity and the relationship of physics to other sciences than by listening to these recordings and reading the book that goes with them. For, of course, Feynman being Feynman, the lectures were not just an introduction to physics for freshmen. They represent a guide to physics as he understood it, the way different pieces fit together, the way to think about things, a philosophy of problem solving.
The originally intended basic course in physics occupies the first two volumes of the published version of the Lectures. At the end of the course, in May 1963, Feynman gave himself the challenge of presenting advanced quantum mechanics to a sophomore audience. Together with a republishing of two introductory chapters from volume one, and some additional material developed in 1964, these final lectures formed the basis of volume three of the Lectures.
The whole package made a huge impact on physics, and physicists, around the world, although not quite in the way that Feynman and his colleagues had originally intended. Feynman’s aim, as he states in the preface to the books, was ‘to address them to the most intelligent in the class’ while also providing ‘at least a central core or backbone of material’ for the less able students. It is generally accepted that the lectures failed the less able students, at least partly, and Feynman’s course did not become the basis of the formal teaching of physics undergraduates at Caltech (or, as far as we are aware, anywhere). By all accounts, the first-year lectures went well. ‘I think’, said Feynman in his preface, ‘that things worked out – so far as the physics is concerned – quite satisfactorily in the first year.’ But while Feynman goes on to comment (referring particularly to the lectures on quantum physics), ‘I don’t think I did very well by the students’, Sands says
in his foreword to volume three, ‘I believe that the experiment was a success.’
One of us (JG) is well placed to explain this seeming dichotomy. I studied physics (at the University of Sussex) from 1963 to 1966, and read the famous ‘red books’ as they were published, from 1963 to 1965, alongside the formal coursework for my degree. The Feynman Lectures came across as a breathtaking insight into how physics really works, a brilliant counterpart to the formal course-work. For anyone who loved physics (not necessarily, as my example shows, the brightest students, but the ones who really cared about the subject), they provided a goldmine of information and opportunities to go beyond the formal teaching. Anyone with sufficient motivation could indeed learn physics, including quantum physics, from the books; but they work best if you already know some of the story.
Feynman’s ‘magnificent achievement’, in the words of Goodstein,7 ‘was nothing less than to see all of physics with fresh new eyes. Feynman was more than merely a great teacher. His lasting monument is that he was a great teacher of teachers.’ And Feynman himself told Goodstein that his most important contribution to physics, in the long run, would not be seen as QED or his other theoretical work, but the Feynman Lectures.8 The point he was surely making is that scientific theories may come and go, being superseded by better theories, but the scientific method, the pleasure of finding things out that he describes so lovingly in these books, is the bedrock upon which all of science is built.
