PEIERLS, RUDOLF ERNST

(b. Oberschöneweide, Berlin, Germany, 5 June 1907; d. Oxford, United Kingdom, 19 September 1995),

solid-state physics, nuclear physics, nuclear fission, nuclear weapons, education, nuclear weapon control.

Peierls is known for his profound contributions to the theory of condensed matter, nuclear structure, and elementary particles, including his pioneering work on the quantum-mechanical theory of solids and the electronic band theory. His demonstration with Otto Frisch of the feasibility of an atomic fission weapon gave rise to the British and American efforts to build the first atomic bombs at Los Alamos, New Mexico, where Peierls led the implosion theory program.

Early Years Peierls was the third child in his immediate family. His father, Heinrich, an electrical engineer from Breslau, had become the managing director of Allgemeine Elektrizitäts-Gesellschaft (AEG) by the time Peierls was born; his mother, Elisabeth, died when he was fourteen. In 1925 after schooling in the local Gymnasium (Humboldtschule) Peierls passed the Abiturium, the high-school graduation examination, and that same year he began his university studies. Some experience in AEG underlined his interests in mathematics rather than engineering, so from 1925, when he began his studies in the Humboldt University, Berlin, he concentrated on theoretical physics.

Peierls joined a higher education system that valued academic freedom and to which anyone who had passed the Abiturium had access. Lectures were not compulsory and there were neither a set of courses that a physics student had to follow nor examinations to pass unless teaching was considered. Often the first examination would be that for a doctorate. An aspiring physicist would expect to choose courses where noted professors worked; it was normal for students to go to various universities during their studies.

There was no real separation between graduates and undergraduates; after eight or twelve semesters a student could finish with a vocational diploma or with a “Staatsexamen” for work in the state service. Promising students could begin their doctorate work after six or seven semesters. This is the course that Peierls took. Courses given by Walther Nernst and Max Planck introduced him to the quantum theory, which interested him very much. After two semesters at Berlin, Peierls moved to Munich, where he remained from 1926 to 1928.

Atomic physics had only recently been transformed by Werner Heisenberg’s invention in 1925 of the matrix formulation of quantum mechanics, and in the following year by Erwin Schrödinger’s introduction of his wave formulation of quantum mechanics. Arnold Sommerfeld, during the 1910s and early 1920s, extended Niels Bohr’s theory of the hydrogen atom so it could deal with complex atoms, but enthusiastically adopted wave mechanics into lectures and research. Sommerfeld introduced quantum mechanics to Peierls, who quickly mastered the formalism. While in Munich Peierls met Hans Bethe, who became a lifelong friend and colleague.

In 1927 Peierls moved to Leipzig, where Heisenberg had founded a school of theoretical physics with which Peierls wished to associate himself. Heisenberg suggested that Peierls should examine the electrical conductivity in metals and should develop further the pathbreaking quantum-mechanical electron theory of metals that Heisenberg’s student Felix Bloch had recently developed. Bloch had approximated a lattice as a three-dimensional periodic potential, ignored the forces between electrons, and effectively had applied the existing theories of hydrogen molecule and formed the basis of the quantum-mechanical theory of solids. From this framework Peierls wrote several influential papers in 1929 and 1930 out of which the modern theory of electronic bands would emerge. Peierls realized that Bloch’s work was flawed by his assumption of the independence of the electrons, and began to seek a theory that would extend the theory to the many-electrons. The application of Bloch’s insights to the anomalous Hall effect suggested that there existed “holes” in nearly filled bands in some solids; and Marcel-Louis Brillouin extended Peierls’s idea to real solids in 1930. Now all the important parts of band theory were available: Bloch’s tight binding, Peierls’s weak binding, general and exact examples, and a fuzzy concept of holes still to be described clearly. In 1931 Alan Wilson drew on the work of Peierls and others to develop a simpler formulation of the band theory, widely used by experimentalists, that offered the first clear explanation of the difference between metals and insulators and for the behavior and nature of semiconductors.

While Heisenberg was away from Leipzig in the spring of 1929, Peierls worked as a research student and later as the Assistent of Wolfgang Pauli, who was the professor of theoretical physics at the Eidgenössische Technische Hochschule in Zürich. During this time Peierls developed a fundamental theory of thermal conductivity in crystals, in which he pointed out how the Umklapp-processes keep the lattice vibrations of solids in equilibrium and limit the electrical and thermal conductivity at low temperatures. For this work he received a PhD from Leipzig in 1929. In 1932, as Peierls’s student days came to an end, he published a major review article that helped to establish the new quantum-mechanical electron theory of metals. In 1932 he gained his Habilitation from the Eidgenössische Technische Hochschule with a paper titled “Zur Theorie der Absorptionsspektren fester Körper.”

During his student years, he traveled to many of the leading universities in Europe, interacting with leaders in the physics community, and finding friends and colleagues with whom he would work and correspond throughout his life. An All-Union Physical Congress held in Odessa in August 1930 was particularly memorable. Not only did he meet Yacov Frenkel and Igor Tamm, but he was introduced to Eugenia Kannegiser, a physics graduate from the University of Leningrad (now Saint Petersburg State University) and a contemporary of Peierls’s friend Lev Landau. The wedding in the spring of 1931 of Eugenia and Rudolf Peierls began their long, close, and very happy marriage. Wherever they lived their household would be open to colleagues and friends. Four children were born to them; Gaby Ellen, Ronald Frank, Catherine (Kitty), and Joanna.

Academic Appointments, 1932–1937 The award of a Rockefeller traveling scholarship in 1932 made it possible for Rudolf and Eugenia Peierls to spend the winter and spring of 1932 in Rome and the summer of 1933 in Cambridge, U.K.: in his own account of his time in Italy and England there are no clear reasons given for his decision to go to these centers of physics research. The impression is given that he wanted to interact with leading workers, not to work with particular men and women. In Rome, despite Enrico Fermi’s interest in nuclear physics, Peierls continued his theoretical work on solids. While in Munich Peierls and others had shown that the complex nature of solids could be understood; hence, while in Rome Peierls developed a quantum-mechanical description of diamagnetism. In Cambridge Peierls met Nevill Mott, who was to contribute notably to solid-state physics. Peierls remained in close touch with Mott for the rest of his life. In the late 1930s, for example, the two corresponded extensively about the theory of rectification that Mott developed with Harry Jones in Bristol.

Toward the end of his Rockefeller Fellowship Peierls had been offered an appointment in Hamburg. However, the political situation in Germany was becoming difficult for Jewish scientists. Although Peierls had been christened as a Lutheran, he was Jewish in background, and with political discrimination beginning he considered that returning to work in Germany would be an error. So during 1933 Peierls sought employment in Britain. Fortunately Manchester University appointed Peierls as an honorary research fellow from 1933 to 1935, using a fund administered by a Senate-Council’s Joint Committee on Assistance to Foreign Scholars, which liaised with the Academic Assistance Council in London. Peierls was granted a third year but resigned during 1935 in order to take up a post with the Mond Laboratory in Cambridge. While in Manchester Peierls collaborated with Bethe and they published several papers in nuclear physics: two on neutrinos, deuterium (they used the name “diplon”) and on the scattering of neutrons by protons. Just before leaving Manchester, Peierls was awarded a honorary DSc.

Between 1935 and the end of 1937 Peierls continued his theoretical work in solid-state physics in Cambridge, as much of the work in the Mond Laboratory was concerned with the physics of solids. Peierls continued on order-disorder problems that fitted in with the interests in the laboratory. In Cambridge he forged links with Maurice Goldhaber, Leo Szilard, and Marcus Oliphant, and continued with his studies of solids. In this he enlarged his superlattice theory of metals, which had stemmed from the researches of William L. Bragg and which had been begun by Evan J. Williams of Manchester, and which Peierls and Bethe had developed further.

Birmingham: 1937–1940 By the spring of 1937 Peierls had published some forty papers, had studied and worked in many of the most significant universities in Europe and had met with and had made friends of many men and women who were or who were about to become leading physicists. In 1936 Marcus Oliphant was appointed to the chair of physics at the University of Birmingham, and shortly afterward asked Peierls if he would be interested in a professorship at that university. As Peierls was interested in the offer from Birmingham, the university founded a chair in applied mathematics and appointed Peierls to it. The post was in the Mathematics Department, for in England theoretical physics was then typically judged as part of mathematics. He was professor of applied mathematics in Birmingham University until 1963.

In Birmingham he found himself the lone theoretician, and, furthermore, there were only a few research students in mathematics, and none in theoretical physics. However, two students, P. L. Kapur and Fred Hoyle, who had started their research in Cambridge, continued to work with him in Birmingham. Kapur coauthored two papers in 1937–1938, before he returned home to India. One of the papers, “The Dispersion Formula for Nuclear Reactions,” became well known, but in a few years was displaced by a method proposed by Eugene Wigner and Leonard Eisenbud. Peierls’s teaching load was not onerous, although he was required to teach a course in hydrodynamics for which some study was necessary.

During his first three years as a professor in Birmingham, Peierls turned increasingly toward the rapidly developing fields of nuclear and elementary particle physics; the majority of his academic papers concerned discoveries made in these fields. He worked on problems on B-particles (1937, 1939), mesons (1939), neutrons (1939), and nuclear forces (1940).

The Second World War: 1940–1945 Peierls had completed two years as a professor in Birmingham when World War II directed many scientists to war work, bringing rapid change to academic work in science. As a German, Peierls was initially considered an enemy alien and thus could not be brought into sensitive war work. He was joined in Birmingham by the Austrian experimental physicist Otto Robert Frisch, also Jewish. Frisch had been trapped in England at the outbreak of the war in late 1939. Roughly a year earlier, during the Christmas holidays of December 1938, Frisch visited his aunt Lise Meitner, also a physicist, who had fled to Stockholm after the German annexation of Austria in March 1938. Together Frisch and Meitner conceived of the notion of nuclear fission, announcing it publicly in early 1939.

In Birmingham, Frisch worked with Peierls to sort out theoretically the question of separating out the²³⁵ Ufissionable isotope from²³⁸ U, the more Abūndant isotope in natural uranium, and making enriched uranium for an atomic bomb. He was also barred from sensitive employment in England because of his enemy alien status. At this point Frisch was living in Birmingham with Rudolf and Eugenia Peierls, in their small flat. Frisch and Rudolf Peierls, perhaps unaware that British scientists had dismissed an atomic bomb, prepared the first thorough analysis of the possibility of building a fission bomb in a March 1940 memorandum. In it they not only suggested that such a bomb was feasible, but also calculated the critical mass of uranium needed for a chain reaction, and found that it might be possible to separate in just a few weeks the few kilograms they computed would be needed to make a bomb. They also suggested a means to control the process and outlined a means of separating the²³⁵ Uisotope to form enriched uranium. And they warned of the radiation dangers after the use of such a bomb.

At a point when winning the war against the Nazis did not look hopeful to these refugees, the 1940 memorandum that Frisch and Peierls wrote on this problem was forwarded, via Peierls’s friend and colleague Marc Oliphant, to James Chadwick and then George P. Thomson, then in charge of uranium research and thus in a position to take action. As the Peierls and Frisch memorandum led directly to the establishment of the projects in Britain and later America to build the atomic bomb, it can be argued that it is one of the most significant scientific papers of the twentieth century. The memorandum led to the organization of the committee, code-named MAUD.

Frisch and Peierls, as enemy aliens, were initially not allowed to take part in the committee’s meetings, but after Peierls pointed out the pointlessness of this exclusion, they were allowed to join part of the discussions. On 26 March 1940 the undersecretary of state at the Home Office signed Peierls’s certificate of naturalization as a British citizen, and his naturalization was registered on 12 April 1940. Now the government was prepared to use the expertise of men and women from enemy nations. In this way Frisch and Peierls were conscripted into the project to explore the possibility of developing an atomic bomb, but they were never included in the main MAUD committee.

Thirty-one of the thirty-four papers that Peierls wrote in 1940 were related to the atomic bomb. A few of his papers were coauthored by his assistant, Klaus Fuchs, who would later became notorious when it was learned that as a member of the theoretical division at Los Alamos, he passed classified secrets to the Soviet Union about the design of the implosion bomb.

During 1940 and most of 1941 Peierls worked on behalf of the Tube Alloys project, the front for the British development of the atomic bomb. Technical matters were the purview of a committee of which Peierls was a member. The preferred method of enriching uranium with²³⁵ U was gaseous diffusion using uranium hexafluoride. It was, however, clear that Britain would not be able to build or run a gas diffusion plant. For this and other reasons, it was important for Britain to join with the United States to develop and produce an atomic bomb. In December 1941 the MAUD committee was disbanded, giving some aggravation to some of its members as Tube Alloys was constructed without them being consulted. According to Margaret Gowing in Britain and Atomic Energy(1964, p. 111), the slights were eased and “leisurely research” continued.

Peierls and other British-based physicists had been in contact with American workers throughout 1941. Some Americans had visited Britain. But coordinated work on building the atomic bomb was not yet being pursued. After the Japanese attack on Pearl Harbor on 7 December 1941 brought the United States into the war, cooperation was more actively pursued. The Americans could draw on their industrial strength in this development. But, as Gowing has discussed, there were political difficulties, particularly concerning problems about secrecy. Cooperation between Britain and the United States on the atomic bomb effort was impossible to carry out across the Atlantic Ocean. Eventually in August 1943, British Prime Minister Winston Churchill and American President Franklin D. Roosevelt made an agreement in Quebec to allow a number of senior British scientist to join the Manhattan Project; they would work in Los Alamos as the “British Mission,” a group that included Peierls, Frisch, and in time nineteen others, including Chadwick and Niels Bohr.

Peierls initially spent some time in New York studying problems related to the diffusion separation method, but he soon moved to Los Alamos, where he took on the important responsibility of leading the Implosion Theory Group, replacing in this role Edward Teller, who had antagonized J. Robert Oppenheimer, the director of the Los Alamos laboratory, as well as Bethe, the head of the Theory Division, by focusing on the problem of the hydrogen bomb rather than the higher priority problem of building an implosion bomb. Among the top-priority problems Peierls coordinated at Los Alamos during the war was finding a realistic description of neutron diffraction through the core of the implosion weapon and developing a theory for the explosive lenses used in assembling the implosion bomb. Peierls was among the many Los Alamos scientists who watched the Trinity test of the first implosion bomb on 16 July 1945 in the Alamogordo desert of New Mexico.

Birmingham: 1945–1963 When Peierls returned to England in the summer of 1945, he had a problem, for he had been offered several professorships in Britain including in Cambridge. He was attracted to Cambridge, but in the end decided to remain in Birmingham, where his title was changed to professor of mathematical physics. His goal was to place the theoretical physics program in his independent department in Birmingham among the world’s leaders. He proved foundational in the growth of his department. His wide experience of physics, his acquaintanceships with contemporaries, his knowledge of many centers, and his inspiring and forthright character enabled him to construct and maintain the high quality of the physics department in Birmingham. His style of working with research students was critical, encouraging, helpful, and generous, and he had a great capacity for work. From the department that Peierls built in Birmingham came a number of physicists who became scientific leaders, for example, Richard Dalitz, Sam Edwards, and Brian Flowers.

By the end of the 1940s, the department was able to attract international scholars of the caliber of Freeman Dyson to Birmingham. In 1948 and 1953 the physics and mathematical physics departments joined forces to organize two international conferences in nuclear physics, which further widened Birmingham’s reputation as a leading center for physics. Peierls’s published papers in the years after the war reflect the wide range of research then being undertaken in theoretical physics. His published books include the textbook, The Quantum Theory of Solids(1955), and the popular book, Atomic Energy (1950).

In the years when Peierls worked in Birmingham he consulted for the Atomic Energy Research Establishment (AERE) in Harwell, United Kingdom, which had been founded 1945. He was particularly valuable to Harwell because of his knowledge and experience in the separation of uranium-235. By 1950 Harwell had become a general research establishment with weapon developments concentrated in Aldermaston, and with its production organization centered around Risley in the north of England. Peierls eventually became more interested in power reactors than in nuclear weapons.

In 1950 Klaus Fuchs, who had worked as an assistant to Peierls at Los Alamos during the war, was unmasked as a spy. At the time he was arrested Fuchs was the head of Harwell’s theoretical physics division. Because Fuchs and Peierls had worked closely together for years, the British secret service carefully investigated Peierls’s interests and background. As the files held in the Public Record Office show, nothing against him was found. He remained as a consultant to the AERE for power reactors.

From 1954, Peierls also consulted with the English Electric Company. By this time, Britain had begun building civil nuclear reactors. For Peierls, contacts with industry had a significance over and above the pure technical and scientific. As he later wrote in his autobiography, “I was always convinced that the experience of thinking physicists could be useful in more practical fields, and …. my contact with English Electric [seemed] to confirm this. I enjoyed these problems and [the] contacts [demonstrated] to my students that their talents could be put to good use outside the narrow academic field” (Bird of Passage, 1985, pp. 279–280). His consulting for the English Electric Company continued until 1969, when the structure of the nuclear industry changed.

Five years later he arranged a second international conference. Conferences and international contacts were important to Peierls. After all, before the war he had moved around Europe from one center of physics to another and began attending conferences from the early years of his researches, and links between Britain and the United States were to the mutual benefit of the participants. By the end of the 1950s theoretical physics in Birmingham was truly world class.

Oxford: 1963–1974 Nevertheless, in 1963 Peierls accepted a professorship in Oxford, where he was named the Wykeham Professor in Theoretical Physics. By this time, theoretical physics was thriving, but it was somewhat diffused at Oxford. Peierls insisted that a department of theoretical physics should be gathered into a suitable, single building. The department quickly became bigger than the one that Peierls had left in Birmingham, and he was not able to operate in the same way that he had previously. In Birmingham because he was the first professor of theoretical physics he was able to control the growth and development from the beginning. In Oxford many structures and interests were already in place. In particular there were fewer social situations available in Oxford in which members of the department, senior and postdoctoral, could meet. Believing frequent intercourse was essential for making good progress in physics, Peierls created a number of initiatives that would help the work of the department become more coherent, for instance, a weekly lunch for senior researchers and postdoctoral visitors. He encouraged and attended most of the more general seminars and colloquia in order to cement a coherence between the researchers. His student Richard Dalitz believed that the increase in coherence may possibly be Peierls’s most important contribution to Oxford during his time there.

When Peierls retired from full-time work in 1974, he accepted a part-time professorship at the University of Washington, Seattle, thereby continuing his association with an institution he first visited in 1962.

Political Activities Peierls played an active role in a number of political organizations relating to the peaceful use of atomic energy. In 1945 he was a founding member of the Atomic Scientists’ Association and served as its first acting president. The aim of the association was to inform the public about matters nuclear, particularly about the hazards of nuclear power. In 1958, when this association wound up its work, it was not clear to what extent it had been successful. Peierls also participated in the Pugwash Movement, which stemmed from a manifesto published in 1955 aimed at nuclear disarmament. He attended Pug-wash conferences in the period 1960–1992 and served as chairman from 1970 to 1972. Peierls’s commitment to nuclear disarmament was also demonstrated by his patronage of FREEZE, the U.K. Coalition for a Nuclear Weapon Freeze. For nearly ten years Peierls was a member of the Advisory Panel on Arms Control and Disarmament, which began its work in 1964 in the Labour government of 1964. By 1974, however, Peierls had grown disillusioned with the work of this panel, as he indicated in a letter to the Conservative government, and he resigned from the panel.

Retirement and Honors After Peierls retired from full-time teaching, he continued a full program of research, lecturing, writing, and traveling, but in the 1980s his health started to decline. He died in Oxford on 19 September 1995, after a productive physics career of more than sixty-five years. Between 1929 and 1995 Peierls authored or coauthored some 378 papers, letters, and books, of which the vast majority were concerned with physics. In the year of his death he published five works.

Peierls received many honors and held numerous visiting posts around the world. There are too many to list here in full, but R. H. Dalitz and Peierls’s Selected Papers(1997) contain a full chronology of Peierls’s life and work. Among his honors were fellow of the Royal Society in 1945, the Royal Society’s Royal Medal in 1959 and its Copley Medal in 1986, CBE in 1946, knighthood in 1968, honorary fellow of the Institute of Physics in 1973, the Guthrie medal in 1968, and the Dirac medal in 1991.

BIBLIOGRAPHY

For archival material, see list in Dalitz (2004), to which should be added files related to Peierls in the Public Record Office, the National Archives, Kew, Richmond, Surrey, TW9 4DU, and some sources in the AIP oral history collection, AmericanInstitute of Physics, One Physics Ellipse, College Park, Maryland 20740-3843 (http://www.aip.org/history).

WORKS BY PEIERLS

“On the Kinetic Theory of Thermal Conduction in Crystals.” Annalen der Physik 3 (1929): 1055–1101.

“On the Theory of Galvanomagnetic Effects.” Zeitschrift für Physiks 53 (1929): 255–266.

“On the Theory of the Hall Effect.” Physiks Zeitschrift 30 (1929): 273–274.

“On the Theory of Electric and Thermal Conductivity of Metals.” Annalen der Physik 4 (1930): 121–148.

“Elektronentheorie der Metalle.” Ergebnisse der Exakten Naturwissenschaften 11 (1932): 264–322.

“Zur Theorie de Absorptionsspektren fest Körper.” Annalen der Physik 13 (1932): 905–952.

“Statistical Theory of Superlattices with Unequal Concentrations of the Components.” Proceedings of the Royal Society, Series A, 154 (1936): 207–222.

Atomic Energy. London: Penguin, 1950.

The Laws of Nature. London: Allen and Unwin, 1955.

The Quantum Theory of Solids. Oxford: Clarendon, 1955.

“The Development of Quantum Theory. Part 1. Formulation and Interpretation.” Contemporary Physics 6 (1964): 129–139.

The Frisch-Peierls memorandum (in two parts): Part I. “On the Construction of a ‘Super-Bomb,’ Based on a Nuclear Chain Reaction in Uranium.” In Appendix 1, Britain and Atomic Energy, 1939–1945, by M. Gowing. London: Macmillan, 1964. Part II. “The Properties of a Radioactive ‘Super-Bomb.’” In Tizard, by R. W. Clark. London: Methuen, 1965.

“The Development of Quantum Theory. Part 2. Consolidation and Extension.” Contemporary Physics 6 (1965): 192–205. Surprises in Theoretical Physics. Princeton, NJ: Princeton University Press, 1979.

Bird of Passage. Princeton, NJ: Princeton University Press, 1985.

More Surprises in Theoretical Physics. Princeton, NJ: Princeton University Press, 1991.

Atomic Histories. Woodbury, NY: American Institute of Physics Press, 1997.

With R. H. Dalitz. Selected Scientific Papers of Sir Rudolf Peierls: With Commentary. London: Imperial College Press, 1997. Contains a complete bibliography, together with a chronology of Peierls’s life.

OTHER SOURCES

Clark, Ronald William. Tizard. London: Methuen, 1965. Dahl, Per F. Superconductivity: Its Historical Roots and Development from Mercury to the Ceramic Oxides. New York: American Institute of Physics Press, 1992.

Dalitz, R. H. “Sir Rudolf Ernst Peierls.” In Oxford Dictionary of National Biography, edited by H. C. G. Matthew and Brian Harrison. Oxford: Oxford University Press, 2004. Contains a list of archival information.

Edwards, S. “Rudolph E. Peierls.” [sic] Physics Today (February 1996): 75–77.

Gowing, Margaret. Britain and Atomic Energy, 1939–1945. London: Macmillan, 1964.

Hendry, John. Cambridge Physics in the Thirties. Bristol, U.K.: Adam Hilger, 1984. Contains essays written by physicists working in Cambridge in the thirties. These, and the introductions, include comments on the relationships between mathematics, theoretical and experimental physics, and the institutional contexts in Cambridge.

Hoddeson, Lillian, Ernest Braun, Jürgen Teichmann, et al., eds. Out of the Crystal Maze: Chapters from the History of Solid-State Physics. New York: Oxford University Press, 1991

———, Paul W. Henriksen, Roger Meade, et al. Critical Assembly: A Technical History of Los Alamos during the Oppenheimer Years, 1943–1945. New York: Cambridge University Press, 1993.

Kapur, P. L. “The Dispersion Formula for Nuclear Reactions.” Proceedings of the Royal Society, Series A, 166 (1938): 277–295.

Mott, N. “Rudolf Peierls (1907–95).” Nature 377 (1995): 577.

Colin Hempstead