Gregor Wentzel (17 February 1898 – 12 August 1978) 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 ...

known for development of

quantum mechanics Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, ...

. Wentzel, Hendrik Kramers, and Léon Brillouin developed the

Wentzel–Kramers–Brillouin approximation In mathematical physics, the WKB approximation or WKB method is a method for finding approximate solutions to linear differential equations with spatially varying coefficients. It is typically used for a semiclassical calculation in quantum mecha ...

in 1926. In his early years, he contributed to

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

spectroscopy Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter ...

, but then broadened out to make contributions to

quantum electrodynamics In particle physics, quantum electrodynamics (QED) is the relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and spec ...

, and

meson In particle physics, a meson ( or ) is a type of hadronic subatomic particle composed of an equal number of quarks and antiquarks, usually one of each, bound together by the strong interaction. Because mesons are composed of quark subparticles, ...

theory.

Life and education

Gregor Wentzel was born in

Düsseldorf Düsseldorf ( , , ; often in English sources; Low Franconian and Ripuarian: ''Düsseldörp'' ; archaic nl, Dusseldorp ) is the capital city of North Rhine-Westphalia, the most populous state of Germany. It is the second-largest city in ...

, Germany, as the first of four children of Joseph and Anna Wentzel. He married Anna "Anny" Pohlmann in 1929 and his only child,

Donat Wentzel Donat G. Wentzel (June 25, 1934 – February 20, 2013) was an American astrophysicist, best known as astronomy educator of undergraduates, graduates, and young researchers. A graduate of the University of Chicago, he established himself in plasma ...

, was born in 1934. The family moved to the USA in 1948 until he and Anny returned to

Ascona, Switzerland 300px, Ascona Ascona ( lmo, label= Ticinese, Scona ) is a municipality in the district of Locarno in the canton of Ticino in Switzerland. It is located on the shore of Lake Maggiore. The town is a popular tourist destination and holds the year ...

in 1970.

Career

Wentzel began his university education in mathematics and physics in 1916, at the

University of Freiburg The University of Freiburg (colloquially german: Uni Freiburg), officially the Albert Ludwig University of Freiburg (german: Albert-Ludwigs-Universität Freiburg), is a public research university located in Freiburg im Breisgau, Baden-Württemb ...

. During 1917 and 1918, he served in the armed forces during

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was List of wars and anthropogenic disasters by death toll, one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, ...

. He then resumed his education at Freiburg until 1919, when he went to the

University of Greifswald The University of Greifswald (; german: Universität Greifswald), formerly also known as “Ernst-Moritz-Arndt University of Greifswald“, is a public research university located in Greifswald, Germany, in the state of Mecklenburg-Western Pom ...

. In 1920, he went to the

Ludwig Maximilian University of Munich The Ludwig Maximilian University of Munich (simply University of Munich or LMU; german: Ludwig-Maximilians-Universität München) is a public research university in Munich, Germany. It is Germany's sixth-oldest university in continuous operatio ...

(LMU) to study under

Arnold Sommerfeld Arnold Johannes Wilhelm Sommerfeld, (; 5 December 1868 – 26 April 1951) was a German theoretical physicist who pioneered developments in atomic and quantum physics, and also educated and mentored many students for the new era of theoretic ...

. Wentzel was awarded his doctorate in 1921 and completed his

Habilitation Habilitation is the highest university degree, or the procedure by which it is achieved, in many European countries. The candidate fulfills a university's set criteria of excellence in research, teaching and further education, usually including ...

in 1922. He remained at LMU as 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 qualific ...

until he was called to the

University of Leipzig Leipzig University (german: Universität Leipzig), in Leipzig in Saxony, Germany, is one of the world's oldest universities and the second-oldest university (by consecutive years of existence) in Germany. The university was founded on 2 December ...

in 1926 as an extraordinarius professor of mathematical physics. In 1926, Wentzel, Hendrik Kramers, and Léon Brillouin independently developed what became known as the

, also known as the '' WKB approximation'', ''classical approach'', and ''phase integral method''. He became ordinarius professor in the Chair for Theoretical Physics, at the

University of Zurich The University of Zürich (UZH, german: Universität Zürich) is a public research university located in the city of Zürich, Switzerland. It is the largest university in Switzerland, with its 28,000 enrolled students. It was founded in 1833 f ...

, when he succeeded

Erwin Schrödinger Erwin Rudolf Josef Alexander Schrödinger (, ; ; 12 August 1887 – 4 January 1961), sometimes written as or , was a Nobel Prize-winning Austrian physicist with Irish citizenship who developed a number of fundamental results in quantum theo ...

, in 1928, the same year

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

was appointed to the

ETH Zurich (colloquially) , former_name = eidgenössische polytechnische Schule , image = ETHZ.JPG , image_size = , established = , type = Public , budget = CHF 1.896 billion (2021) , rector = Günther Dissertori , president = Joël Mesot , a ...

. Together, Wentzel and Pauli built the reputation of Zurich as a center for theoretical physics. In 1948, Wentzel took a professorship at the

University of Chicago The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park neighborhood. The University of Chicago is consistently ranked among the b ...

. He retired in 1970 and went to spend his last years in

Ascona 300px, Ascona Ascona ( lmo, label= Ticinese, Scona ) is a municipality in the district of Locarno in the canton of Ticino in Switzerland. It is located on the shore of Lake Maggiore. The town is a popular tourist destination and holds the yea ...

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

. In 1975, he was awarded the

Max Planck Medal The Max Planck medal is the highest award of the German Physical Society , the world's largest organization of physicists, for extraordinary achievements in theoretical physics. The prize has been awarded annually since 1929, with few exceptions, ...

Bibliography

Books

* Gregor Wentzel. ''Einführung in die Quantentheorie der Wellenfelder.'' Franz Deuticke, 1943, 1946. Ann Arbor, Michigan: J.w. Edwards, 1943, 1946. (Translated by Charlotte HoutermansCharlotte Houtermans nee Riefenstahl was married to Fritz Houtermans. and J. M. Jauch, with an Appendix by J. M. Jauch. ''Quantum Theory of Fields.'' Interscience, 1949. Dover, 2003.) * Gregor Wentzel. ''Lectures on Strong Coupling Meson Theory at the University of Rochester.'' 1954. * Gregor Wentzel and notes by K. K. Gupta. ''Lectures on Special Topics in Field Theory.'' Lectures on Mathematics and Physics: Physics. Tata Institute of Fundamental Research, 1957. * Gregor Wentzel. ''Lectures on Special Topics in Quantum Mechanics.'' Lectures on Mathematics and Physics. Physics, 3. Tata Institute of Fundamental Research, 1965.

Articles

* Arnold Sommerfeld and Gregor Wentzel. ''Über reguläre und irreguläre Dublett'', Zeitschrift für Physik 7 86–92 (1921) as cited i
Sommerfeld Bibliography

Notes

References

* Jungnickel, Christa and

Russell McCormmach Russell Keith McCormmach (born 9 October 1933), the husband of the late Christa Jungnickel, is an American historian of physics. McCormmach grew up in Walla Walla, Washington and studied physics at Washington State College with bachelor's degree i ...

. '' Intellectual Mastery of Nature: Theoretical Physics from Ohm to Einstein, Volume 1: The Torch of Mathematics, 1800 to 1870.'' University of Chicago Press, paper cover, 1990. * Jungnickel, Christa and Russell McCormmach. ''Intellectual Mastery of Nature. Theoretical Physics from Ohm to Einstein, Volume 2: The Now Mighty Theoretical Physics, 1870 to 1925.'' University of Chicago Press, Paper cover, 1990. * Mehra, Jagdish, and

Helmut Rechenberg Helmut Rechenberg (born November 6, 1937, in Berlin; died November 10, 2016, in Munich) was a German physicist and science historian. Rechenberg studied mathematics, physics and astronomy at the University of Munich and graduated in 1964. At Mun ...

. ''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 5 Erwin Schrödinger and the Rise of Wave Mechanics. Part 2 Schrödinger in Vienna and Zurich 1887–1925.'' Springer, 2001. * Schiff, Leonard I. ''Quantum Mechanics.'' McGraw-Hill, 3rd edition, 1968.

External links

* Thomas S. Kuhn
Oral History Transcript – Gregor Wentzel.
Niels Bohr Library and Archives, American Institute of Physics, 1964. * Peter G. O. Freund, Charles J. Goebel, Yoichiro Nambu, and Reinhard Oehme
Gregor Wentzel 1898–1978 – A Biographical Memoir.
National Academy of Sciences, 2009. * S.Antoci and D.-E.Liebscher
''The Third Way to Quantum Mechanics is the Forgotten First.''
Annales Fond.Broglie 21 (1996) 349.

– ETH Bibliothek. * {{DEFAULTSORT:Wentzel, Gregor 1898 births 1978 deaths 20th-century German physicists Quantum physicists Ludwig Maximilian University of Munich faculty Leipzig University faculty University of Zurich faculty University of Chicago faculty University of Greifswald alumni Ludwig Maximilian University of Munich alumni Theoretical physicists Mathematical physicists Members of the United States National Academy of Sciences Winners of the Max Planck Medal