Léon Rosenfeld (; 14 August 1904 in

Charleroi Charleroi (, , ; ) is a city and a municipality of Wallonia, located in the province of Hainaut, Belgium. It is the largest city in both Hainaut and Wallonia. The city is situated in the valley of the Sambre, in the south-west of Belgium, not ...

– 23 March 1974) was a Belgian

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

and a

communist Communism () is a sociopolitical, philosophical, and economic ideology within the socialist movement, whose goal is the creation of a communist society, a socioeconomic order centered on common ownership of the means of production, di ...

activist. Rosenfeld was born into a

secular Secularity, also the secular or secularness (from Latin , or or ), is the state of being unrelated or neutral in regards to religion. The origins of secularity can be traced to the Bible itself. The concept was fleshed out through Christian hi ...

Jewish Jews (, , ), or the Jewish people, are an ethnoreligious group and nation, originating from the Israelites of History of ancient Israel and Judah, ancient Israel and Judah. They also traditionally adhere to Judaism. Jewish ethnicity, rel ...

family. He was a polyglot who knew eight or nine languages and was fluent in at least five of them. Rosenfeld obtained a

PhD A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of graduate study and original research. The name of the deg ...

at the

University of Liège The University of Liège (), or ULiège, is a major public university of the French Community of Belgium founded in 1817 and based in Liège, Wallonia, Belgium. Its official language is French (language), French. History The university was foun ...

in 1926, and he was a close collaborator of the physicist

Niels Bohr Niels Henrik David Bohr (, ; ; 7 October 1885 – 18 November 1962) was a Danish theoretical physicist who made foundational contributions to understanding atomic structure and old quantum theory, quantum theory, for which he received the No ...

from 1930 until Bohr's death in 1962. Rosenfeld published in 1930 the first systematic Hamiltonian approach to Lagrangian models that possess a local gauge symmetry, which predates by two decades the work by

Paul Dirac Paul Adrien Maurice Dirac ( ; 8 August 1902 – 20 October 1984) was an English mathematician and Theoretical physics, theoretical physicist who is considered to be one of the founders of quantum mechanics. Dirac laid the foundations for bot ...

and Peter Bergmann. Rosenfeld contributed to a wide range of physics fields, from statistical physics and quantum field theory to astrophysics. Along with Frederik Belinfante, he derived the Belinfante–Rosenfeld stress–energy tensor. He also founded the journal ''

Nuclear Physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies th ...

'' and coined the term

lepton In particle physics, a lepton is an elementary particle of half-integer spin (Spin (physics), spin ) that does not undergo strong interactions. Two main classes of leptons exist: electric charge, charged leptons (also known as the electron-li ...

. In 1933, Rosenfeld married Yvonne Cambresier, who was one of the first women to obtain a Physics PhD from a European university. They had a daughter, Andrée Rosenfeld (1934–2008) and a son, Jean Rosenfeld.

Awards and honors

Rosenfeld held chairs at multiple universities: Liège,

Utrecht Utrecht ( ; ; ) is the List of cities in the Netherlands by province, fourth-largest city of the Netherlands, as well as the capital and the most populous city of the Provinces of the Netherlands, province of Utrecht (province), Utrecht. The ...

Manchester Manchester () is a city and the metropolitan borough of Greater Manchester, England. It had an estimated population of in . Greater Manchester is the third-most populous metropolitan area in the United Kingdom, with a population of 2.92&nbs ...

, and

Copenhagen Copenhagen ( ) is the capital and most populous city of Denmark, with a population of 1.4 million in the Urban area of Copenhagen, urban area. The city is situated on the islands of Zealand and Amager, separated from Malmö, Sweden, by the ...

. In 1949 Léon Rosenfeld was awarded the Francqui Prize for Exact Sciences.

Works

* * * Demonstrated the logical consistency of quantum electrodynamics.

References

External links

*
Oral history interview transcript for Léon Rosenfeld on 3 September 1968, American Institute of Physics, Niels Bohr Library & Archives
1904 births 1974 deaths Belgian Jews Scientists from Charleroi Belgian physicists Jewish physicists University of Liège alumni Members of the German Academy of Sciences at Berlin {{Belgium-scientist-stub