Wilhelm Lenz (February 8, 1888 in

Frankfurt am Main Frankfurt am Main () is the most populous city in the States of Germany, German state of Hesse. Its 773,068 inhabitants as of 2022 make it the List of cities in Germany by population, fifth-most populous city in Germany. Located in the forela ...

– April 30, 1957 in

Hamburg Hamburg (, ; ), officially the Free and Hanseatic City of Hamburg,. is the List of cities in Germany by population, second-largest city in Germany after Berlin and List of cities in the European Union by population within city limits, 7th-lar ...

) was a German

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 ...

, most notable for his invention of the

Ising model The Ising model (or Lenz–Ising model), named after the physicists Ernst Ising and Wilhelm Lenz, is a mathematical models in physics, mathematical model of ferromagnetism in statistical mechanics. The model consists of discrete variables that r ...

(named after his student, Ernst Ising), and for his application of the

Laplace–Runge–Lenz vector In classical mechanics, the Laplace–Runge–Lenz vector (LRL vector) is a vector (geometric), vector used chiefly to describe the shape and orientation of the orbit (celestial mechanics), orbit of one astronomical body around another, such as a ...

to the old quantum mechanical treatment of

hydrogen-like atom A hydrogen-like atom (or hydrogenic atom) is any atom or ion with a single valence electron. These atoms are isoelectronic with hydrogen. Examples of hydrogen-like atoms include, but are not limited to, hydrogen itself, all alkali metals such as ...

Biography

In 1906, Lenz graduated from the Klinger-Oberralschule, a non-classical secondary school in Frankfurt, and went to study mathematics and physics at the

University of Göttingen The University of Göttingen, officially the Georg August University of Göttingen (, commonly referred to as Georgia Augusta), is a Public university, public research university in the city of Göttingen, Lower Saxony, Germany. Founded in 1734 ...

. From 1908 to 1911, Lenz studied under

Arnold Sommerfeld Arnold Johannes Wilhelm Sommerfeld (; 5 December 1868 – 26 April 1951) was a German Theoretical physics, theoretical physicist who pioneered developments in Atomic physics, atomic and Quantum mechanics, quantum physics, and also educated and ...

, at the

University of Munich The Ludwig Maximilian University of Munich (simply University of Munich, LMU or LMU Munich; ) is a public university, public research university in Munich, Bavaria, Germany. Originally established as the University of Ingolstadt in 1472 by Duke ...

, and he was granted his doctorate on March 2, 1911. Upon graduation, he stayed on at the University, became Sommerfeld’s assistant on April 1, 1911, and he completed his

Habilitation Habilitation is the highest university degree, or the procedure by which it is achieved, in Germany, France, Italy, Poland and some other European and non-English-speaking countries. The candidate fulfills a university's set criteria of excelle ...

on February 20, 1914, becoming a

Privatdozent ''Privatdozent'' (for men) or ''Privatdozentin'' (for women), abbreviated PD, P.D. or Priv.-Doz., is an academic title conferred at some European universities, especially in German-speaking countries, to someone who holds certain formal qualifi ...

on April 4, 1914. During

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

, he served as a radio operator in

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

and was awarded the

Iron Cross The Iron Cross (, , abbreviated EK) was a military decoration in the Kingdom of Prussia, the German Empire (1871–1918), and Nazi Germany (1933–1945). The design, a black cross pattée with a white or silver outline, was derived from the in ...

Second Class in 1916. From September 30, 1920, he was again an assistant to Sommerfeld at the University of Munich’s Institute of Theoretical Physics, and he was appointed to the title and rank of extraordinarius professor at the University, on November 11, 1920. On December 1, 1920 he became an extraordinarius professor at the

University of Rostock The University of Rostock () is a public university located in Rostock, Mecklenburg-Vorpommern, Germany. Founded in 1419, it is the third-oldest university in Germany. It is the oldest university in continental northern Europe and the Baltic Se ...

. From 1921, until his retirement in 1956, he was at the

University of Hamburg The University of Hamburg (, also referred to as UHH) is a public university, public research university in Hamburg, Germany. It was founded on 28 March 1919 by combining the previous General Lecture System ('':de:Allgemeines Vorlesungswesen, ...

, as Ordinarius Professor of Theoretical Physics and Director of the Institute of Theoretical Physics.Lenz
– ETH Zurich
– Litten The formation of the new chair and institute for theoretical physics at Hamburg was a result of advances being made in Germany on

atomic physics Atomic physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. Atomic physics typically refers to the study of atomic structure and the interaction between atoms. It is primarily concerned wit ...

and

quantum mechanics Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Addison-Wesley, 1989, It is ...

and the personal intervention of Sommerfeld, who helped many of his students get such professorships. At Hamburg, Lenz trained Ernst Ising and

J. Hans D. Jensen Johannes Hans Daniel Jensen (; 25 June 1907 – 11 February 1973) was a German nuclear physicist. During World War II, he worked on the German nuclear energy project, known as the Uranium Club, where he contributed to the separation of uranium ...

; his assistants there included

Wolfgang Pauli Wolfgang Ernst Pauli ( ; ; 25 April 1900 – 15 December 1958) was an Austrian theoretical physicist and a pioneer of quantum mechanics. In 1945, after having been nominated by Albert Einstein, Pauli received the Nobel Prize in Physics "for the ...

Pascual Jordan Ernst Pascual Jordan (; 18 October 1902 – 31 July 1980) was a German theoretical and mathematical physicist who made significant contributions to quantum mechanics and quantum field theory. He contributed much to the mathematical form of matri ...

, and Albrecht Unsöld.Unsöld was a former doctoral student of Sommerfeld, who got his degree in 1927. Se
Unsöld
– Mathematics Genealogy Project. Together with Pauli and

Otto Stern :''Otto Stern was also the pen name of German women's rights activist Louise Otto-Peters (1819–1895)''. Otto Stern (; 17 February 1888 – 17 August 1969) was a German-American physicist. He is the second most nominated person for a Nobel Pri ...

, Lenz built up the Institute into an international center for nuclear physics. They maintained close scientific and personal exchanges with the institutes for theoretical physics at the Universities in Munich (Sommerfeld), Göttingen (

Max Born Max Born (; 11 December 1882 – 5 January 1970) was a German-British theoretical physicist who was instrumental in the development of quantum mechanics. He also made contributions to solid-state physics and optics, and supervised the work of a ...

), 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 ...

(

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 ...

). When Lenz retired in 1956 he was succeeded by Harry Lehmann.

Books

*Wilhelm Lenz ''Einführungsmathematik für Physiker'' (Verlagsanstalt Wolfenbüttel, 1947)

Notes

References

* Mehra, Jagdish, and Helmut Rechenberg ''The Historical Development of Quantum Theory. Volume 1 Part 1 The Quantum Theory of Planck, Einstein, Bohr and Sommerfeld 1900 – 1925: Its Foundation and the Rise of Its Difficulties. ''(Springer, 2001) *Mehra, Jagdish, and Helmut Rechenberg ''The Historical Development of Quantum Theory. Volume 1 Part 2 The Quantum Theory of Planck, Einstein, Bohr and Sommerfeld 1900 – 1925: Its Foundation and the Rise of Its Difficulties.'' (Springer, 2001) *Mehra, Jagdish, and Helmut Rechenberg ''The Historical Development of Quantum Theory. Volume 5 Erwin Schrödinger and the Rise of Wave Mechanics. Part 1 Schrödinger in Vienna and Zurich 1887–1925.'' (Springer, 2001) {{DEFAULTSORT:Lenz, Wilhelm Scientists from Frankfurt 20th-century German physicists 1888 births 1957 deaths Academic staff of the University of Hamburg Academic staff of the University of Rostock University of Göttingen alumni Ludwig Maximilian University of Munich alumni Recipients of the Iron Cross (1914), 2nd class