Rosenfeld, Léon Jacques Henri Constant (1904-1974)

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Léon Rosenfeld in Copenhagen 1963 source:Wikimedia commons

Physicist and atomic scientist, born in Charleroi on 14 August 1904 and died in Copenhagen on 23 March 1974.

Biography

Léon Rosenfeld was born in Charleroi on 14 August 1904, the son of an engineer. He attended secondary school at the Atheneum of Charleroi. In 1922, he enrolled at the University of Liège. Where he obtained a doctorate in physics and mathematics in 1926.
After obtaining his doctorate, he went abroad to study. He studied for one year at the École normale supérieure in Paris. Here he met Paul Langevin (1872-1946), Léon Brillouin (1889-1969) and Louis de Broglie (1875-1960). In 1927, he went to Göttingen, where he worked for two years as an assistant to Max Born (1882-1970). Then he went to Zurich, where he worked for Wolgang Pauli (1900-1958). In 1929 he met Niels Bohr (1885-1962) at a congress in Copenhagen, after which several visits to Copenhagen followed suit. He became a close associate of Niels Bohr with who he continued to work together until the Bohr's death in 1962.
In 1930, he returned to Belgium and became responsible for the course on radiation physics at the University of Liège. In 1933, statistical mechanics was added. In 1936, he became lecturer of the course on elements of theoretical and mathematical physics. In 1937 he was promoted to full professor. In 1940, he accepted the chair of theoretical physics at the University of Utrecht. He continued to combine this position with his professorship at the University of Liège for a year. However, the war circumstances forced him to give up his functions at the ULg in 1941. During the war he lived in Utrecht. In 1947, he accepted an offer to become director of the Department of Theoretical Physics at the University of Manchester.

In 1958, at the request of Niels Bohr, he started working at the Nordisk Institutet for Teoretisk Atomfysik (Nordita). He settled permanently in Copenhagen. However, he did not break all ties with our country. For example, he was appointed director of the Laboratory for High Energy at the Interuniversity Institute for Nuclear Science. He therefore regularly returned to Belgium.
In the 1970s he began to work closely with the group around Ilya Prigogine.

He was elected corresponding member of the Académie royale des Sciences, des Lettres et des Beaux-Arts de Belgique on 6 June 1959. He was a member of the Royal Academy of Denmark, of the Académie septentrionale (Paris), a foreign member of the Academy of the Federal Republic of Germany and a corresponding member of the Brazilian Academy. He received honorary doctorates from the University of Copenhagen and the ULB. In 1926, he was a laureate of the travel grant competition. In 1930 he won the Agathon De Potter Prize and in 1949 the Francqui Prize.

He died in Copenhagen on 23 March 1974.

Work

Léon Rosenfeld made fundamental contributions to various domains in physics.
During his stay in Paris, he was introduced to the theoretical aspects of physics and acquired a basic knowledge of quantum mechanics. Before moving to Zurich, Léon Rosenfeld mainly did research in wave mechanics. In Göttingen he worked on molecular physics, where he concerned himself with the formation of molecules in galaxies with temperatures colder than the sun.
In Zurich, he made an important contribution to the development of the theory of quantum electrodynamics.
He worked with Niels Bohr on the foundations of quantum mechanics. He furthermore worked on the effects of gravitation.

During his stay in Utrecht, he conducted research into nuclear physics and mesons.
In Manchester he published Nuclear Forces, a basic work on nuclear physics.Here he continued his work on atomic and nuclear physics.
He founded the journal Nuclear Physics in 1956 and was its chief editor. In Copenhagen, he continued to work on the theory developed by Bohr even after his death.
In the 1970s, he collaborated with Ilya Prigogine. Léon Rosenfeld gave new meaning to the irreversibility of thermodynamics.

History of science

In 1927, he founded the History of Science Society. He became a member of the National Committee for Logics, History and Philosophy of Science in 1933. In 1928, he published the article: Le premier conflit entre la théorie ondulatoire et la théorie corpusculaire de la lumière.

Philosophy of science

He reflected on the philosophical implications of quantum mechanics. He published on this subject: L'évolution de l'idée de causalité,Strife about complementarity, The Measuring Processing Quantum Mechanics, On the foundations of statistical thermodynamics, Le conflit épistémologique entre Einstein et Bohr and Questions of irreversibility an ergodicty.

Publications

• A list with his publications can be found in: Houziaux, Léo,"Léon Rosenfeld", In: Annuaire ARB, 2005, Brussel: ARB, p. 46-57.
  

Bibliography

• Houziaux, Léo,"Léon Rosenfeld", In: Annuaire ARB, 2005, Brussel: ARB, p. 39-46.
• Serpe, Jean, "Léon Rosenfeld", In: Nouvelle Biographie Nationale, vol. 2, Brussel, ARB, 1990, p.317-321.
• MARAGE, Pierre, "La physique nucléaire et la physique des particules élémentaires", in Robert Halleux, Geert Vanpaemel, Jan Vandersmissen en Andrée Despy-Meyer (red.), Geschiedenis van de wetenschappen in België 1815-2000, Brussel: Dexia, 2001, vol. 2, p. 86.