Brian Pippard interviewed by Alan Macfarlane 31st March 2008
0:09:06 Born in Earls Court, London, 1920; when I was three we moved to Cardiff where my father became head of the Engineering Department at Cardiff University, the first Chair that he held; moved to Bristol when I was eight when my father got the Chair at Bristol; went to Clifton College where the teaching was extremely good; I think that in the whole of my school career I never had a bad teacher; the science department at that time was the best in the country; there were also good mathematicians; above all I was taught the piano by Douglas Fox who was a musician of the first quality; had a happy home life, with one older brother; both my parents were born in Yeovil, Somerset; father's father was a builder; know less about my mother's family but her grandmother was the widow of a publican; I was brought up in a lower middle class family where my father was the first one to go to university; both parents were extremely kind and we were good children; when the First World War broke out, my father was just graduating and went to work for the Air Ministry on the strength of aeroplane structures; afterwards set up as a consultant for a year or two before taking the Chair at Cardiff; after Bristol he went to Imperial College; father never overtly encouraged me but I knew that science would be a good thing to do; about the age of fourteen when I took School Certificate I was under pressure from school to do classics, Douglas Fox wanted me to do music, but knew that my father would prefer me to be a scientist; by good fortune science won; my heart was not in classics although I found it easy; I didn't want to be a professional musician; David Willcox was my contemporary at Clifton and was so extraordinarily good that I knew I wasn't in that class; I have played the piano ever since; believe that music supplies that part of one's mind which mathematics doesn't touch, so no affinity; I enjoy Viennese classics, Haydn, Mozart, Beethoven, Schubert and Brahms; I was absolutely hopeless at games; I was a reading boy; I like to read slowly and critically and have always read a lot; always had a strong feeling for Kipling
12:24:18
The head of science at Clifton was Dr E.J. Holmyard
who was well know for his textbooks on chemistry; a formal teacher who lectured
rather than taught, but they were so good; W.C. Badcock
who was the head of physics was also a good teacher who loved the subject,
although he was a martinet of a man; I did learn from them how important it
is to love your subject when you are teaching it; among my other teachers,
one of the most interesting was the head of the Preparatory School, Forbes
Mackintosh, and a mathematician, Sammy Wells, who made it fun; I came up to
Clare College, Cambridge, in 1938 fully intending to be a chemist; I had done
well in physics but had received advice from several people that physics was
a subject where you had to be very good at mathematics; I did one year of
Natural Sciences tripos then the war came; my tutor
said that they did not seem to want chemists in the war but did want physicists;
if I switched to physics I could avoid being called up and could return to
chemistry after the war; as soon as I went to a few physics lectures I knew
that that was what I wanted to do and have never changed my mind since; in
the first year Alec Wood was an amusing teacher; after the war started my
teachers and supervisors were terrible, all the good ones had gone to work
on radar; I spent most of my third year in the University Library reading;
as soon as I got my degree I was drafted into radar work; it was Army radar,
the ‘Cinderella’ as far as radar was concerned; I learnt a lot in four years
working on transmission lines, wave guides, aerials, things where physics
come in all the time; by the time the war was over and I left the establishment
I was fully competent in the new microwave techniques;
I knew more than almost anybody at that time; I came back to
19:06:18 Contemporaries of mine both at Cambridge and during the war was Jeff Hanner of Trinity and John Robson of King's; they both went on to do excellent work; John Robson went to Chalk River in Canada when the war was over and I think was the first person to measure the lifetime of a neutron in the free state; they are both dead now but we remained very good friends all our lives; worked in the old Cavendish building where Bragg had just taken over; J.J. Thomson once came but we thought him a wreck by then; Paul Dirac was there but I didn't know him until much later; when I came back after the war the Mond Laboratory was run by Jack Allen who left for St Andrews soon after, and David Shoenberg was my supervisor and we remained friends for the rest of his life; the Mond was a very nice lab. to work in; the layout was spacious with a big hall in the middle; when we came to build a New Cavendish in West Cambridge I was chairman of the building committee and I suggested that all the members should sketch what an ideal physics lab. would be like; I built a model on the basis of the Mond, of how to extend an open space with rooms to get away in; the architect liked that and it became the basis of the new building; it was Kapitsa's idea in the first instance; open spaces are very important so that people pass by the work rooms and get a vague idea that something is going on there; in the New Cavendish, the passages on the first floor look down into the open spaces
25:09:15 Ph.D. was on superconductivity; later I moved on to the behaviour of electrons in ordinary metals; that was something about which very little was known when I was a research student; the problem is that electrons move around in solids pretty well freely because their wave motion enables them to pass by atoms without being deflected but their dynamics are changed; the relation between energy and momentum is not only different for an electron in a solid but it differs with direction; if you plot coordinates of momentum and plot the energy of an electron, if it was a free electron the constant energy surface would be a sphere, in a real metal that is not so, you get all sorts of curious distortion of shape; the difference between one metal and another lies very strongly in the difference in shape of this so called Fermi surface; when I started virtually nothing was known about it; the theoreticians had played around with it but the equations were too difficult to solve; David Shoenberg became the world expert in the use of an effect called the De Haas-vanAlphen effect for studying these; this has turned out to be by far the most important way so studying these problems; but before David got onto this I thought of another way using microwaves to get some information and managed to get the shape of the surface in copper; I got it more or less right; that was a most enjoyable game; it was jolly hard work analysing the results but it was worth doing
29:15:06 There were two brothers, Fritz and Heinz London, Jewish refugee scientists from Germany; in 1935 they hit on simple equations which describe the motion of electrons in superconductors, electrons moving without resistance and these London equations are at the heart of most discussions of superconductivity; they are explicable in quantum mechanic terms; some of the work I was doing in the early 1950's made me doubt if they were quite correct and I modified them into a non-local form, that is to say that the current at any one point is not related to the field at that point but related to fields all round it; sorry to say that Fritz London was rather upset and thought I had made a mistake; sadly he died very shortly afterwards; David Shoenberg just before the war went for a year to Russia; his father was Russian although he was brought up in England; he want to work for Kapitsa for a year to get his low temperature work started in Moscow; while he was there he wrote a small textbook on superconductivity; years afterwards I asked David why he had said so little about the London equations in the book; he said that Landau, the great Russian theorist, didn't approve of them and thought they were wrong; in 1957 I went to Moscow to a conference; I had already produced my modification of the London equations and I was severely taken to task by Landau and Ginzberg and all the Russians; we had a most marvellous shouting match at one another; what I do love about the Russians is they can shout at you without offence and can be shouted back at; it is purely intellectual shouting as far as the physicists were concerned; they told me how wrong I was to swallow the London equations; Landau thought there was nothing in them but by 1957 he thought they were the absolute heart of the matter and anyone who was going to change them was practically immoral; Landau was a very great man; I have a sort of classification for top physicists, those who are enviable and those who are beyond envy; Heisenberg whom I had quite a lot of conversations with I regarded as enviable because we talked the same language, he just did it better; Landau was beyond envy, he seemed to have a private line to truth; one didn't follow his argument, and he wasn't always right, but there was a greatness about his thought; the only other beyond enviable man I knew was Lars Onsager, Norwegian by birth who went to Yale when he was quite young; Mott and Bragg were with Heisenberg in the enviable category; if I had known Dirac he would have been in the beyond envy category but I wasn't in that sort of physics; Maxwell, Einstein and Newton are the three outstanding ones; Rutherford I would regard as being very high in the enviable class, Thomson similarly; they were the same sort of physicist as me only so much better; Cockcroft, I never understood, he was so silent; he had been Chief Superintendent of the radar establishment where I worked; he used to walk into the lab. and stand beside you smiling; I was warned early on that when Cockcroft comes in don't wait for him to speak but just tell him what you are doing; he didn't like initiating conversation; Chadwick had gone to Liverpool after the war; I met him once or twice, again a very remote creature; Bragg was very friendly
38:24:23 I never took to computing; one of the troubles with being a scientist in Cambridge in those days was that we had secretaries; you never typed anything but wrote in longhand and it was typed for you; when word processors came in your secretary had to learn how to use them but you didn't waste your time doing it; thus I have remained totally ignorant of these things; on the future of superconductivity, there is not the hope that was projected for it transmitting power over thousands of miles without any loss; I cannot see any sign that that is going to happen yet; one of the troubles is that the materials are very peculiar, they have to be made very carefully, they are brittle and if they break they can't just be stuck together again; electrical engineers are wholly opposed to the idea of sending vast amounts of power through something that is brittle which may break down at any moment; helium cooled superconductors have been seriously considered but the criticism of the engineers has always been, if they go wrong you have to heat up the whole system, take it apart, mend it, put it together again, cool it down, so it is going to be out of action for weeks; high temperature superconductors are worse than that; the low temperature ones can be quite malleable and strong, the high temperature ones, no; they will have uses in small applications; I haven't followed the work very well; when the supposed breakthrough in the 1990's came out I was immediately repelled by it; not by an idea that was something that I had not thought of, but by the first papers that were written by people in America who were clearly totally ignorant of anything that had gone before in superconductivity; I was getting old anyhow so was really beyond serious work so it doesn't matter much