Leon Rosenfeld: Physics, Philosophy, And Politics In The Twentieth Century

Physics, Philosophy, and Politics in the Twentieth Century

Anja Skaar Jacobsen

• Publisher: WSPC
• Year: 2012
• ISBN:
  9789814452083
• Topic: Biological Sciences
• Subtopic: Science General
• Index: Biological Sciences

Léon Rosenfeld (1904–1974) was a remarkable, many-sided physicist of exceptional erudition. He was at the center of modern physics and was well-known as Niels Bohr's close collaborator and spokesman. Besides he reflected deeply on the history and philosophy of science and its social role from a leftist perspective. As both actor and acute spectator of modern physics and as a polyglot cosmopolitan whose life crossed those of many important people in both the East and West, as well as by virtue of his close collaboration and friendship with Bohr, Rosenfeld was an important figure in twentieth century physics. His biography illuminates the development, popularization, and reception of quantum physics and its interpretation in addition to the development of the political Left. The book draws extensively from previously untapped, unpublished sources in more than five languages.

Contents:

• Physicist of the Second Quantum Generation
• Rosenfeld in Copenhagen
• Physics, Philosophy, and Politics in the 1930s
• Surviving the War in Utrecht
• Cold War and Political Commitment
• Bohr's Cold Warrior

Readership: Students and professionals studying the history of science.

Chapter 1

Physicist of the Second Quantum Generation

The first chapter takes us through Rosenfeld’s education and follows his tracks around Europe as assistant professor and postdoc at some of the centers of theoretical physics in the late 1920s. The scientific context of Rosenfeld’s early career was primarily the development and consolidation of quantum physics and its combination with relativity theory beginning in 1926. In 1929, he began making his own important contributions to this research area. The pioneers of quantum theory included Max Planck, Albert Einstein, Niels Bohr, Arnold Sommerfeld, followed by Werner Heisenberg, Wolfgang Pauli, Pascual Jordan, P. A. M. Dirac, Erwin Schrödinger, Louis de Broglie, Oskar Klein, Hendrik Anthony Kramers, among others. Rosenfeld can be characterized as a physicist of the second quantum generation including Rudolf Peierls, Lev Davidovich Landau, Enrico Fermi, Christian Møller, Jacques Solomon, Matvei Bronstein, George Gamow, Hans Bethe, among others.¹ Generation here does not refer to age in a strict sense, but rather to the timing of the research of the physicists in question. Other characteristics can be used to divide the generations of theoretical physicists. Suman Seth has recently argued that during the early twentieth century, theoretical physics emancipated itself from experimental physics; a new generation of theoretical physicists, including Heisenberg, Pauli, Dirac, Klein and Kramers, comprised theoreticians who did not have a solid training in laboratory practice like the older generation.² Rosenfeld can be described as a physicist of the second quantum generation in both senses.

“You see, I was Belgian”

Léon Jacques Henri Constant Rosenfeld was born in the mining town of Charleroi in the Walloon part of Belgium on 14 August, 1904, and grew up as an only child. Belgium is a country with two major peoples, the Dutch-speaking Flemish in the north and the French-speaking Walloons in the south-east, sharply separated by both language and culture. It was one of the first countries to be industrialized on the European continent with metallurgy and coal mining primarily in the Walloon part; the Flemish part was predominantly agrarian. During the industrialization, the bourgeoisie gained social dominance and shaped the social, political, and economic life, mixing with Belgium’s traditional aristocracy. French was the official language even in Flemish areas and dominated higher education. In the early twentieth century, during the so-called second industrial period, Belgium was ruled by the Catholic Party and during its reign a strong tradition in engineering was cultivated.³ Rosenfeld’s father, Léon Rosenfeld (1872–1918), was a Jewish Russian immigrant from St. Petersburg who married a Belgian, Jeanne Marie-Laure Mathilde Pierre (1880–1955). He was an electrical engineer and inventor working for an electrical company. There seems to have been no contact between him and his family in Russia. However, his father’s Russian background may have initiated Rosenfeld Jr.’s curiosity and interest in Russia and the Russian language. His father’s background as a migrating Jew may also have affected Rosenfeld Jr. His father distanced himself from the Jewish community; their home was secular and Rosenfeld Jr.’s position became atheistic. His father’s example may have prepared Rosenfeld Jr. for not finding a migrating identity alien; he does not seem to have been particularly tied to Belgium.

Rosenfeld’s father died in an accident at the factory during the First World War when Rosenfeld Jr. was only 14. Naturally, this traumatic incident deeply and emphatically affected Rosenfeld Jr.’s life. The premature death of his father had a marked impact on his immediate choices and dispositions in life. His primary intellectual interests were initially history, Greek, Latin, and natural history, but his father’s premature death made him turn to study natural science and mathematics, “to be like his father”, despite the poor prospects in that field in Belgium at the time and his mother’s opposition to this choice.⁴

However, Rosenfeld’s background and interest in the human sciences came to mark his activities for the rest of his life, also as a physicist. He stood out from most of his later physicist colleagues as one who sought the philosophical meaning on a deeper level and traced the conceptual roots of physics. Already during his student years, Rosenfeld published numerous small pieces about history of science in Bulletin Scientifique de l’Association des Elèves des Ecoles Spéciales at the University of Liége.⁵ Wherever he worked, whether in Liège, Utrecht, Manchester, or Copenhagen, Rosenfeld engaged with philosophers and historians of science as well as with physicists and astrophysicists. Early on in the twentieth century, other scholars in Belgium also had strong interest in the history of science, notably George Sarton, the later founder of the American History of Science Society and the leading journal in the field, Isis. Sarton was a progressive, secular humanist who regarded history of science as the human activity demonstrating the progress of mankind.⁶ Besides Sarton, Rosenfeld was well-acquainted with the mathematician and historian of science Jean Pelseneer, whose approach to the history of science was rather conservative. Both Sarton and Pelseneer were involved with the institutionalization of the history of science in Belgium and internationally.⁷ Already in 1927, Rosenfeld published two papers in Isis.

Apart from the great loss of his father, Rosenfeld seems to have grown up in “a close and warm family life, not particularly rich, but not in poverty either”.⁸ According to Rosenfeld’s daughter Andrée, “after his father’s early death his maternal uncle took care of the well being of him and his mother and played an important role as a father figure in his later childhood”.⁹ Rosenfeld was quite close to his mother and assumed a great measure of responsibility for her. He brought his mother along with him (and later with him and his wife, Yvonne) to Copenhagen when he was living there at frequent intervals in the 1930s. His mother suffered from grave illness in the 1930s and during the Second World War, when Rosenfeld went to a great deal of trouble to visit her in Belgium from the Netherlands. After the war, she came to live with the Rosenfelds in Manchester.¹⁰

Rosenfeld began his mathematics and physics studies in 1922 at the University of Liège, which was in fact more of an engineering school, but a good one, and he graduated in 1926 with great distinction.¹¹ At this time he began his lasting friendship with another student, the later professor of spectroscopy and astrophysics at the same university, Polydore Swings.¹² Belgium had a strong tradition in engineering, but the country was rather peripheral with respect to modern physics. This fact lay behind the first sentence in Rosenfeld’s story about his life as a physicist when interviewed by Thomas S. Kuhn and John Heilbron in 1963, “You see I was Belgian”;¹³ he did not have the best starting point for a career in theoretical physics. According to Rosenfeld, the teaching he received was at a very low level. The students were introduced to neither relativity theory nor quantum theory, and Rosenfeld studied these topics on his own during his last year at university.¹⁴ For a comparison, it may be mentioned that not even at the Institute for Theoretical Physics in Copenhagen was quantum mechanics part of the curriculum until 1928. However, in Copenhagen graduate students could follow lectures and seminars and discuss the recent developments in quantum mechanics with the many visiting physicists.¹⁵

During their studies, the professor of topography at the University of Liège, Marcel Dehalu, played an important role as patron for Rosenfeld and Swings. When he received the Francqui Prize in 1949, Rosenfeld described how Dehalu never stopped encouraging, guiding, and giving him support and sympathy and, at the same time, never tried to restrict Rosenfeld’s activities or influence the orientation of his work. Rosenfeld further expressed gratitude to all those who had made it possible for him to follow the studies of his own choice.¹⁶ After his graduation Rosenfeld obtained scholarships from the Belgian government, the University Foundation, and the patrimony of the University of Liège to continue his studies in physics at the prestigious Ecole Normale Superieure in Paris.¹⁷

Paris 1926–1927: Physics and Socialism

In Paris Rosenfeld took courses and was supervised by Paul Langevin, Léon Brillouin, and Louis de Broglie. Besides physics and mathematics he was introduced to the strong tradition of the history of science and philosophy at the Sorbonne. Here Rosenfeld attended Abel Rey’s lectures “La Science Grecque”.¹⁸ However, Rosenfeld’s main interest lay at the very frontier of theoretical physics, the combination of quantum theory and relativity, and for a while he worked with de Broglie. According to Rosenfeld, de Broglie, who came from a noble family, was extremely shy and isolated even from other physicists in Paris, but the equally shy Rosenfeld still managed to establish relatively good contact with him. De Broglie, who was a pioneer in quantum physics, was the first with whom Rosenfeld discussed how to make sense of the new quantum theory. By drawing an analogy to the duality of light, which Einstein had suggested in 1905 could be described as both waves and particles, de Broglie proposed in 1923 that material particles like the electron possess a similar dual nature. He attributed to such particles a wavelength, since called the de Broglie wavelength. It was on this basis that the theory of wave mechanics that united the physics of light and matter was created a few years later by Erwin Schroödinger.¹⁹ Under de Broglie’s supervision Rosenfeld worked on combining relativity with wave mechanics, developing the wave equation in five dimensions, a topic which the Swedish physicist Oskar Klein was also working on independently at the time.

Besides being introduced to quantum theory, it was also in Paris that Rosenfeld’s political and social awakening began. “In Paris I got the first glimpse of social problems and international politics … It was only in Paris by listening to the animated discussions of the people that I realized that there was a problem there that was worth thinking about”.²⁰ At Langevin’s lectures on statistical mechanics at the Collège de France, Rosenfeld met another physics student, Jacques Solomon, and the two soon ...

Table of contents

• Cover Page
• Title Page
• Copyright Page
• Preface
• Contents
• List of Pictures
• Introduction
• Chapter 1. Physicist of the Second Quantum Generation
• Chapter 2. Rosenfeld in Copenhagen
• Chapter 3. Physics, Philosophy, and Politics in the 1930s
• Chapter 4. Surviving the War in Utrecht
• Chapter 5. Cold War and Political Commitment
• Chapter 6. Bohr’s Cold Warrior
• Epilogue
• Bibliography
• Index