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An Informal History

The Development of Theoretical Physics in Oxford

This article, written by Professor Sir Roger Elliott, was first published in the IOP History of Physics Group Newsletter, August 2007, No. 22.

 

Theoretical Physics in a recognisable prototype form of what we have today only began in Oxford after the Second World War. Before that there was no such tradition within Physics although the subject was represented in the Mathematics Faculty by the Rouse Ball Professor, Edward Milne and later Charles Coulson. In the interwar years Lindemann had been rebuilding Oxford Physics from its moribund state but his priorities were clearly in the experimental area. Here he used his extensive contacts with German physicists to help many scientists who were being persecuted by the Nazis and he succeeded in bringing some to Oxford to create a world class low temperature group with Francis Simon, Kurt Mendelssohn, and Nicholas Kurti and in strengthening the spectroscopy group with Heinrich Kuhn. There were opportunities on the theoretical side but for various reasons these did not mature. Einstein himself spent some time in Christ Church before being tempted away to Princeton although his interaction with the physicists appears to have been modest. Schrödinger was for a time a Fellow of Magdalen although his erratic behaviour and unconventional lifestyle alienated many of his supporters. He returned to Vienna, only to be rescued again by Eamon DeValera to his Institute in Dublin. Max Born was also approached but he preferred to go to Edinburgh apparently because of his dislike of Lindemann.

Maurice Pryce

Part of the problem was the lack of a permanent post to lead Theoretical Physics and one possibility was a dedication of the Wykeham Chair to this subject. The idea was apparently first suggested by Bragg when he became an elector in 1938 but there was an insuperable obstacle in the person of John Townsend. He had held the Chair since its inception in 1900 and although initially he had done important work on ionised gases and had built up the Electrical Laboratory in the form we now call the Townsend Building, he had long since ceased to be active in research and showed little interest in teaching. He was already over 70 but in those days there was no retirement age. Eventually pressure from the University forced him to retire but by then the war had started and everything was on hold. (There is a story, probably apocryphal, that when asked why he did not resign he replied that he was waiting for his knighthood to recognise his lifelong contributions to science. Lindemann supposedly then arranged this and he was indeed knighted just before his resignation.) Lady Townsend remained active in local politics into the post-war years. After the war it was agreed that the Chair should be allocated to Theoretical Physics and attached to the Clarendon Laboratory which had now absorbedTownsend’s Electrical Lab. It was advertised with a salary of £1200 p.a. (with children’s allowances).

The elector’s choice fell on Maurice Pryce, (above). Others known to show interest included Heitler, London and Wheeler but the electors took the bold option of electing someone only 32 years old who showed exceptional promise. In fact he looked so much younger than his years that he was once challenged by the Proctors in the Kings Arms who thought he was an undergraduate. At Trinity College, Cambridge, in the early 1930’s, Pryce had been regarded as one of the brightest mathematicians of his generation. Fred Hoyle, in his autobiography says that Pryce was much the cleverest of his contemporaries; he calls him a ‘wizard’. 

He did important work with Born on early versions of field theory and made contributions to neutrino physics, demolishing in a classic paper the briefly fashionable view that photons might consist of pairs of neutrinos. He worked in Princeton with Pauli and von Neumann before returning to Cambridge and moving to Chadwick’s department at Liverpool just before the war.

Pryce in his reminiscences mentions two highlights from his scientific career. At Princeton he had an introduction to Einstein from Born and went along with some trepidation to see the great man. He found Einstein deep in conversation with Rosen and immediately included Pryce into that discussion, showing considerable interest in his views and insights even though he was a strong supporter of the Bohr interpretation of Quantum Mechanics. On a second occasion when he presented one of his papers in Cambridge, Dirac spontaneously offered to communicate the results to the Royal Society. Indeed Dirac was a strong supporter in his application for the Chair.

During the war Pryce led a team at the Admiralty Research Station and made an important contribution to the theory and practice of the propagation of radio waves and radar, and subsequently with the Anglo Canadian team working on the design of reactors. During his time at Liverpool he had worked on fission but later declined to be involved in the atomic bomb project. He was therefore a man with very extensive interests and knowledge of physics.

Once in Oxford he rapidly built up a large group of research students. At that time there were many people returning from war service, some from the military and some from scientific occupations and they were all anxious to get on with their studies. These included Anatole Abragam, who went on to have an important influence on the rejuvenation of French physics, John Ward, whose contributions to field theory are well known, Ken Stevens in magnetism, Roger Blin-Stoyle a former president of the IOP, David Brink in nuclear structure, John Ziman who worked in solid state and later in the sociology of physics, and several others. Pryce’s technique was to offer only broad advice and let people find their own specific problems. While this was conspicuously successful in some cases there were some casualties who ended up with what were effectively insoluble problems for the time. There was only one other permanent appointment in Theoretical Physics, Stanley Rushbrooke whose interests and knowledge in thermodynamics and statistical mechanics attracted Simons attention. Cyril Domb who had worked with Pryce at the Admiralty held a short term position though he eventually went back to Cambridge and then to Kings College London. Nevertheless there was a core to make an active theoretical physics group and Pryce instituted regular seminars, and a journal club which met in the evenings in Balliol, and some graduate lectures. I still remember how totally incomprehensible were those given by John Ward, but then he was famously taciturn and brief. His thesis for example was only 26 pages long which might serve as a model for some of our graduates but did contain the proof of “Ward’s Identity”. Pryce’s own research was in magnetism and the nuclear shell model and he developed a close collaboration with the groups doing paramagnetic resonance under Brebis Bleaney and others.

Pryce however was frustrated by his position within the Clarendon Laboratory where every administrative and financial decision had to be referred to Lord Cherwell as he had then become. Accommodation in the Townsend Building was very cramped – indeed part of it was an incompletely converted gentlemen’s lavatory.

On one occasion John Ziman and I asked Pryce if we could have an electric calculating machine, a Marchant, to replace the hand Facit machines which were then in use. Pryce said he had no money and we had to ask Cherwell ourselves which we did with some trepidation. He received us courteously, showed us how to use a slide rule (with which he claimed to have won the war) and sent us away. But we did eventually get the machine.

For this reason, and possibly for personal ones, Pryce accepted an invitation to replace Neville Mott as the Head of Department in Bristol when the latter moved to the Cavendish Chair in Cambridge.

Willis Lamb

The file relating to the subsequent election to the Wykeham Chair is still closed but it appears that the electors faced a dilemma since there were no applicants. Several feelers were put out and Weiskopf headed the group for a time as a Visiting Professor but in the end the electors made, what seemed to many, a surprising choice. Willis Lamb was an American with little previous contact with Oxford but he had some obvious attractions. He was already a Nobel Laureate and his work, both theoretical and experimental, exploited spectroscopy and microwaves, both techniques which were widely in use in the Clarendon. Lamb was also a highly versatile physicist with a wide knowledge of the subject. He was therefore able to nurture the broad interests of the large group which Pryce had left behind, although he took no research students of his own. He also interacted strongly with the low temperature group under Kurti. His personality and American background also left him at a disadvantage when faced with the complexities of the Oxford system. Although technically Theoretical Physics had now become a separate department as part of the package to attract him, together with other inducements such as a designated parking place, not all the promised new appointments materialised, and it was essentially fully parasitic on the Clarendon Laboratory.

In the meantime great changes were taking place in Oxford Physics with the creation of the Nuclear Physics Department under Denys Wilkinson. It had been decided that there should be a large research institution based in a university to carry forward research in nuclear physics outside the Atomic Energy Establishments where for historical reasons this was then concentrated. Oxford was an obvious choice because of its proximity to Harwell and Denys Wilkinson was an inspired leader. At a stroke the size of Oxford Physics was doubled with a large number of new appointments and Wilkinson not surprisingly demanded a separate department so that the generous financing could be separately administered. This put considerable pressure on the Theoretical Physics group since those like Roger Blin-Stoyle, Brian Buck and David Brink who were working in the nuclear area were naturally attracted to work closely with this new group while those of us with interests in condensed matter felt more closely allied with the experimental groups in the Clarendon Laboratory. It looked for a while as if the department would dissolve and the pattern, not unknown elsewhere, where the theorists mixed with experimentalists in the same discipline, rather than with each other, was the norm.

It was at this point that Lamb decided that he would return to the US and the electors made what seemed the obvious choice by appointing Rudi Peierls. By then it was universally recognised that he had created in Birmingham the largest and most successful group of theoretical physicists in the country.

On accepting the Chair, Peierls made it clear that he wanted to recreate an effective Department of Theoretical Physics in a similar form, though of course adapted to the Oxford system. For this to happen he recognised that such a department needed its own premises and he was promised that new accommodation would be provided in the continued expansion plans for Oxford Physics. In the meantime the department was allocated 12 and 13 Parks Road which, with some outstations as the department grew, were to be the Department throughout this tenure. Because they were supposed to be temporary, conditions were relatively Spartan but this did not affect the spirit of the group.

  

Rudolf Peierls

The transition to the new premises was made by Ter Haar who had been appointed as Reader by Lamb, again with Simon’s influence, to provide some expertise in statistical mechanics, although his interests in astrophysics were an added bonus. Once Rudi had arrived he set about creating the atmosphere for a department which still lingers today. Coffee at 11.00 and a weekly picnic lunch (supplied by Mrs Palm from the Market) increased the interaction between all branches of the Department. A more formalised programme of graduate lectures was instituted to ensure that graduate students got a wide grounding in all aspects of theoretical physics. His concept of theoretical physics as a unified subject using common techniques though in different experimental areas was the philosophy which led the Department and still does so today. He also brought to Oxford a number of important new appointments.

Dick Dalitz came with his Royal Society Research Professorship; John Taylor, Ian Aitchison, Robin Stinchcombe and others all joined us in this period. Although the diffuse nature of Oxford with its conflicting loyalties between College and Department meant it was not possible to recreate the family atmosphere which had prevailed at Birmingham, Peierls created a strong sense of community.

One of the things that never happened was the promised new building as the unfinished walkways in the Keble Road Triangle testify. Not only did the money run out but a change in fashion meant that it was now impossible to knock down the row of Victorian houses in Keble Road to create that building on the corner of Parks Road where it had been planned.

As I know personally Peierls never relinquished the promise he had been given believing that it would strengthen the hand of his successor even if he could not use it himself. And indeed that proved to be the case since when I succeeded him I was able to bargain with the University for the reasonably acceptable and comfortable accommodation which we still occupy in Keble Road. It is not the new building which Peierls wanted but it is at least a functioning home for a Department which has served Theoretical Physics for 30 years. During this period I and my successor David Sherrington have attempted to maintain and develop the tradition of a unified department of Theoretical Physics emphasising common techniques and approaches.

          

Left to right, David Sherrington and Tony Leggett

The group has normally included about one hundred physicists with a distinguished staff (including more FRS’s than the rest of Oxford Physics all together) many postdocs and visitors. Several hundred graduate students have passed through and it is this training and the moulding of our approach which is the most important contribution. There are too many to mention in detail but a number have gone on to achieve great things in science and outside. They include one Nobel Prize winner, Ter Haar’s student Tony Leggett.

The traditions have continued into a reunified Physics Department where as a Sub-Dept, Theoretical Physics still inhabits the separate premises in Keble Road. It has expanded further with an “outstation”, the Dalitz Centre for the Elementary Particle Group in the Wilkinson Building. But finally, Theoretical Physics is to get the New Building it was promised 50 years ago growing out of the hole now being dug in front of the Clarendon. Sadly, it has proved difficult to fill the Wykeham Chair, but the department is as large and active as ever.