Jointly published by Akadémiai Kiadó, Budapest and Springer, Dordrecht
Scientometrics, Vol. 62, No. 3 (2005) 343–350
Klaus Fuchs – The enduring contribution to physics from his British period MANFRED BONITZ Dresden (Germany) Klaus Fuchs, during his years in England as an immigrant, has written 20 scientific papers. One of these papers, published in 1938, became a fundamental text in solid state physics and for the development of microelectronics in succeeding decades. It was cited more than 1200 times in the period from 1945 until 2003. It appears to be a typical case of delayed recognition in science. Pioneering papers simultaneously written by Hahn & Straßmann and by Meitner & Frisch on the discovery of nuclear fission are considered for comparison.
Introduction – Who was Klaus Fuchs? In the Encyclopedia Britannica we read: “Fuchs, (Emil) Klaus (Julius) (b. Dec. 29, 1911, Rüsselsheim, Ger.–d. Jan. 28, 1988, East Germany), German-born physicist and spy who was arrested and convicted (1950) for giving vital American and British atomic-research secrets to the Soviet Union. Fuchs studied physics and mathematics at the universities of Leipzig and Kiel and joined the German Communist Party in 1930. He was forced to flee Germany after the Nazis came to power in 1933, and he ended up in Great Britain, where he studied at the University of Edinburgh and received a doctorate there. He was briefly interned as a German at the start of World War II but was soon released in order to do research on the atomic bomb at the University of Birmingham. In 1942 he became a British citizen. When Fuchs realized the importance of the research he was engaged upon, he began passing scientific secrets on to the Soviet Union. In 1943 he was sent to the United States to work on the atomic bomb project at Los Alamos, where he acquired a thorough knowledge of the theory and design of the bomb and passed his knowledge on to the Soviets. His espionage is credited with saving the Soviets at least one year’s work in their own program to develop the atomic bomb. After the war he returned to England, where he became head of the physics department of the British nuclear research centre at Harwell. His espionage activities Received July 1, 2004 Address for correspondence: MANFRED BONITZ Halbkreisstraße 17, D–01187 Dresden, Germany E-mail:
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M. BONITZ: Klaus Fuchs’ enduring contribution to physics
were finally detected and he was arrested in 1950, upon which he admitted passing information to the Soviet Union since 1943. He was sentenced to 14 years in prison. After his release in 1959 for good behaviour, he went to East Germany, where he was granted citizenship and was appointed deputy director of the Central Institute for Nuclear Research, Rossendorf (near Dresden). He remained a committed Communist and received many honours from the East German Communist Party and the scientific establishment there.” (Copyright 1994–1999 Encyclopædia Britannica) In the Great Soviet Encyclopedia, 1970–1977 we read not a single word about Klaus Fuchs! A horrible scenario of the Cold War in the XXth century is reflected here: on the one side - Klaus Fuchs, the “atom spy”, thus an enemy of the western nations; on the other, the Soviet side – “we do not know a person Klaus Fuchs, our atomic achievements are exclusively due to Soviet scientists and engineers”. The truth appears slowly – with the “perestroika”, the end of the Cold War, and the opening of the archives of the secret services. New books and movies are uncovering the unbelievable biography of Klaus Fuchs. It is not the aim of this paper to list them. What we would like to focus on here is his excellence as a physicist-theoretician. Klaus Fuchs’ ideas and work significantly promoted the development not only of the first atomic bombs, but also the hydrogen bomb.1 Furthermore, as experts in the fields of solid state physics and microelectronics know, Klaus Fuchs produced numerous fundamental papers. Their citation history reveals high citation rates and in some cases points to delayed recognition. One particular paper is unceasedly cited also in present days.
The scientific papers by Klaus Fuchs 1935–1943 Klaus Fuchs wrote during his English period 20 scientific papers. Sir Nevill Mott, with whom Klaus Fuchs worked for four years in Bristol, where he in 1936 got his first doctoral degree (Doctor of Philosophy), recalls: “...that he was an extremely talented physicist-theoretician can be seen by his wonderful papers which are cited also in our times. If there had not been the war, and if he could have stayed in Great Britain, he certainly would have become ... a professor at a British university.
1G.
GONTSCHAROW, Vorgeschichte und Jahre auf dem Weg zur Wasserstoffbombe: Zur Rolle von Klaus Fuchs, paper at the colloquium ’Ethik in der Wissenschaft - Die Verantwortung der Wissenschaftler. Zum Gedenken an Klaus Fuchs’, Berlin, November 14–15, 2003, proceedings to be published by the LeibnizSocietät.
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I wouldn’t have been able, of course, to forecast whether he might have received a Nobel prize, or whether he would have also become a Fellow of the Royal Society. But for a man of his calibre I foresaw a great career in physics.” 2 In the following paragraphs we give (bold face) for each of Fuchs’ papers the number of citations received in the time span between 1945 – 2003. A further look back, for instance until the year 1936 is not yet possible because the used database Web of Science3 reaches back only to the year 1945. It could be expected that the citation rates for the papers under our consideration might be higher, since, in general highest citation rates are achieved in the years following publication. Cases of delayed recognition are exceptions and deserve special consideration. (GLÄNZEL et al., 2003). The (1938) paper [4] by Klaus Fuchs, titled: The Conductivity of Thin Metallic Films According to the Electron Theory of Metals, is undoubtedly such a case. In order to illustrate the contents of this paper we quote from its Introduction: “The conductivity of thin films of the alkali metals has recently been measured in the H. W. Wills Physical Laboratory, Bristol. It was found that as the thickness of the film is decreased to that of a few atomic layers the conductivity drops below that of the bulk metal. In the papers quoted the hypothesis was put forward that this effect is due to the shortening of the mean free paths of the conduction electrons of the metal by collisions with the boundaries of the film. The experimental results were compared with a formula derived on the basis of this hypothesis. This formula was, however, obtained subject to a number of simplifying assumptions, and it is the first purpose of this paper to obtain a more accurate formula. I also compare this formula with experiment, and make certain deductions about the surfaces of thin films.” Electron theory of metals (1935–1942) [1] A Quantum Mechanical Investigation of Cohesive Forces of Metallic Copper. Proc. Roy. Soc. (London), A151(1935), 585-602. 323 citations [2] A Quantum Mechanical Calculation of the Elastic Contants of Monovalent Metals. Proc. Roy. Soc. (London), A153(1936), 622-639. 381 citations [3] The Elastic Contants and Specific Heats of the Alkali Metals. Proc. Roy. Soc. (London), A157 (1936), 444-450. 202 citations [4] The Conductivity of Thin Metallic Films According to the Electron Theory of Metals. Proc. Cambr. Phil. Soc., 34(1938), 100-108. 1272 citations [5] Operator Calculus in the Electron Theory of Metals. Proc. Roy. Soc. (London), A176 (1940), 214-228. 12 citations 2From
E. PANITZ, Treffpunkt Banbury oder wie die Atombombe zu den Russen kam. Klaus Fuchs, Ruth Werner und der größte Spionagefall der Geschichte. Das Neue Berlin, Berlin 2002, p.114. Translation by M.B. 3 Online-Version WoS, Institute for Scientific Information (ISI – Thomson Scientific, Philadelphia, PA, USA)
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[6] Crystal Theory of Metals: Calculation of the Elastic Constants. (with H. W. Peng). Proc. Roy. Soc. (London), A180 (1942), 451-476. 13 citations Statistical mechanics (1938–1943) [7] The Statistical Mechanics of Condensing Systems. (with M. Born). Proc. Roy. Soc. (London), A166 (1938), 391-414. 84 citations [8] The Vapor-Pressure Curve. Proc. Roy. Soc. (London), A179 (1942), 194-201. 0 citations [9] Statistical Mechanics of Binary Systems. Proc. Roy. Soc. (London), A179, (1942), 340-361. 32 citations [10] The Statistical Mechanics of Many Component Gases. Proc. Roy. Soc. (London), A179 (1942), 408-432. 31 citations [11] Pressure Dependence of the Equilibrium Constant of Ammonia. Proc. Roy. Soc. (London), A179 (1942), 433-438. 1 citation [12] On the Statistics of Binary Systems. Proc. Roy. Soc. (London), A181 (1943), 414-415. 1 citation Theory of relativity and quantum field theory (1938–1940) [13] On the Invariance of Quantized Field Equations. Proc. Roy. Soc. (Edinburgh), LIX (1938/39), Part II, 109-121. 2 citations [14] On Fluctuations in Electromagnetic Radiation. (with M.Born). Proc. Roy. Soc. (London), A170 (1939), 252-265. 1 citation [15] The Mass Centre in Relativity. (with M. Born). Nature, 145 (1940), 587, 933. 1 citation [16] Reciprocity, Part II: Scalar Wave Functions. (with M. Born). Proc. Roy. Soc. (Edinburgh), LX (1939/40), Part I, 100-116. 5 citations [17] Reciprocity, Part III: Reciprocal Wave Functions. (with M. Born). Proc. Roy. Soc. (Edinburgh), LX (1939/40), 141-146. 9 citations [18] Reciprocity, Part IV: Spinor Wave Functions. Proc. Roy. Soc. (Edinburgh), LX (1939/40), 147-163. 4 citations Theory of the atomic nucleus (1939–1940) [19] On the Stability of Nuclei Against ß-Emission. Proc. Cambr. Phil. Soc., 35 (1939), 242-255. 5 citations [20] On the Statistical Method in Nuclear Theory. Proc. Roy. Soc. (London), A174 (1940), 509-522. 0 citations
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Citation history of Klaus Fuchs’ papers Electron theory of metals The papers belonging to this subfield represent in total the highest number of received citations, although with significant differences among the papers, see Figure 1. The outstanding paper is [4] The Conductivity of Thin Metallic Films According to the Electron Theory of Metals, which has received 1272 citations. Remarkable is the time patterns of these citations: the citation rate is very low at the beginning, then, in the 1960s, the paper experiences a steep growth in recognition with a high level of citing over a very long period right up to recent years. Among the other papers of this subfield, most are “normally” cited (papers [1], [2], and [3] respectively), that is, after reaching their maximum, citations slowed down. Papers [5] and [6] are not significant from a citational point of view.
Figure 1. The citation time scale covers a span of 60 years from 1944 until 2003 (in two year steps). The curve of the most cited paper will be repeated in the next figure for comparison
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Statistical mechanics, Theory of relativity, Quantum field theory, Theory of the atomic nucleus The papers in the other subfields are not cited beyond average rates. Most cited are the papers [7] and [10], one together with Max Born, both in the subfield Statistical Mechanics. A comparison with two famous papers published simultaneously by other authors Klaus Fuchs published his most cited paper [4] in 1938, the year of the discovery of nuclear fission. Therefore, it seems intriguing to look, for comparison, at the citation history of two pioneering papers on nuclear fission published at the same time. Most cited papers on nuclear fission by Hahn & Straßmann and Meitner & Frisch. [21] Hahn, O., Straßmann, F. Über den Nachweis und das Verhalten der bei der Bestrahlung des Urans mittels Neutronen entstehenden Erdalkalimetalle. Naturwissenschaften, 27, (Januar 1939), 11-15. 190 citations [22] Meitner, L., Frisch, O.R. Disintegration of Uranium by Neutrons: a New Type of Nuclear Reaction. Nature, 143 (1939) 239-240. 121 citations Citation history of the three pioneering papers. Figure 2 presents the number of citations received by each of the three pioneer papers since their publication in 1938 and 1939, by Fuchs, by Hahn & Straßmann, and by Meitner & Frisch respectively. Citing journals. The 1272 references to the most cited Fuchs paper [4] are contained in 180 scientific journals, however, half of these references are found in only eight journals (numbers of references in brackets): Physical Review (168), Thin Solid Films (137), Journal of Applied Physics (102), Journal of Physics (86), Physica Status Solidi A (39), Surface Science (37), Zhurnal Eksperimentalnoi i Teoreticheskoi Fiziki (35), Journal of Materials Science (34).
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Figure 2. The citation time scale covers a span of 60 years from 1944 until 2003 (in two year steps)
The 190 references to the Hahn & Straßmann paper are contained in 91 scientific journals, half of these references are found in 16 journals: Physical Review (14), Nuclear Physics (11), Uspekhi Fizicheskikh Nauk (7), Radiochimica Acta (7), Journal of Radioanalytical and Nuclear Chemistry (6), Review of Modern Physics (6), Nature (5), Angewandte Chemie International Edition (5), American Journal of Physics (5), Isotopenpraxis (5), Chemiker-Zeitung (4), Pramana (4), Nucleonics (4), Kernenergie (4), Journal of Chemical Education (4), Zeitschrift Für Naturforschung (3). The 121 references to the Meitner & Frisch paper are contained in 61 scientific journals, half of these references (59) are found in 11 journals: Nuclear Physics (11), Physical Review (7), Uspekhi Fizicheskikh Nauk (7), Nature (6), American Journal of Physics (6), Review of Modern Physics (5), Angewandte Chemie International Edition (5), Physics Today (3), Physics Reports (3), Journal of Chemical Education (3), Pramana (3). Discussion It is well-known, that the numerous papers of Nobel prize winners are in general highly cited. However, the conclusion that highly cited authors are already of “Nobel Scientometrics 62 (2005)
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class” (a term coined by Eugene Garfield) is not permitted, although this conclusion seems to be inevitable in the case of Klaus Fuchs. A similar situation exists with regard to the awarding of Nobel prizes; the rule states that these prizes cannot be awarded posthumously. Even after Fuchs’ death in 1988, the prediction made by his British doctoral supervisor, Sir Nevill Mott, that Fuchs would have a ‘great career in physics’ is indeed borne out in the citation history of Fuchs’ prewar publications. We do not possess a comprehensive theory of scientific citing. Too manifold are the reasons for a scientist to cite, or not to cite another scientist. An assessment of the three compared pioneering papers on the basis of mere citation counts is neither intended nor possible. The decision about the impact of Klaus Fuchs’ papers is a challenging task for the experts in their fields. His continuing citedness in the field of solid state physics adds further to the colourful mosaic of the life and work of Klaus Fuchs; an enigmatic and outstanding scientific personality of the 20th Century. * Extended version of a paper at a colloquium ‘Ethik in der Wissenschaft – Die Verantwortung der Wissenschaftler. Zum Gedenken an Klaus Fuchs’, Berlin, November 14–15, 2003 I am grateful to Prof. Klaus Fuchs-Kittowski, Berlin, a nephew of Klaus Fuchs, who probably possesses the most profound knowledge about the personality of Klaus Fuchs; and I wish to express my gratitude to Dr. Mari Davis, UNSW Australia, past president of ISSI, for her deep interest in the topic from a Scientometrician’s point of view, for her valuable comments, and for raising my English to a more or less international standard.
References GLÄNZEL, W., B. SCHLEMMER, B. THIJS (2003), Better late than never? On the chance to become highly cited only beyond the standard bibliometric time horizon. Scientometrics, 58 (3) : 571–586.
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