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 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 ...

. Wentzel,

Hendrik Kramers Hendrik Anthony "Hans" Kramers (17 December 1894 – 24 April 1952) was a Dutch physicist who worked with Niels Bohr to understand how electromagnetic waves interact with matter and made important contributions to quantum mechanics and statistical ...

, and

Léon Brillouin Léon Nicolas Brillouin (; August 7, 1889 – October 4, 1969) was a French physicist. He made contributions to quantum mechanics, radio wave propagation in the atmosphere, solid-state physics, and information theory. Early life Brilloui ...

developed the

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

in 1926. In his early years, he contributed to

X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

spectroscopy Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Spectro ...

, but then broadened out to make contributions to

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

, superconductivity and

meson In particle physics, a meson () 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, the ...

theory.

Biography

Early life and family

Gregor Wentzel was born in

Düsseldorf Düsseldorf is the capital city of North Rhine-Westphalia, the most populous state of Germany. It is the second-largest city in the state after Cologne and the List of cities in Germany with more than 100,000 inhabitants, seventh-largest city ...

, Germany, as the first of four children of Joseph and Anna Wentzel. He married Anna Lauretta Wielich and his only child,

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

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

Ascona, Switzerland file:AsconaAnsicht.jpg, 300px, Ascona Ascona ( ) is a municipalities of Switzerland, municipality in the district of Locarno (district), Locarno in the Cantons of Switzerland, canton of Ticino in Switzerland. It is located on the shore of Lake M ...

in 1970.

Education and academia

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

University of Freiburg The University of Freiburg (colloquially ), officially the Albert Ludwig University of Freiburg (), is a public university, public research university located in Freiburg im Breisgau, Baden-Württemberg, Germany. The university was founded in 1 ...

. During 1917 and 1918, he served in the armed forces 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 then resumed his education at Freiburg until 1919, when he went to the

University of Greifswald The University of Greifswald (; ), formerly known as Ernst-Moritz-Arndt University of Greifswald, is a public research university located in Greifswald, Germany, in the state of Mecklenburg-Western Pomerania. Founded in 1456, it is one of th ...

. In 1920, he went to the

Ludwig Maximilian 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 ...

(LMU) to study 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 ...

. 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 Germany, France, Italy, Poland and some other European and non-English-speaking countries. The candidate fulfills a university's set criteria of excelle ...

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 qualifi ...

until he was called to the

University of Leipzig Leipzig University (), 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 1409 by Frederick I, Electo ...

in 1926 as an extraordinarius professor of mathematical physics. He became ordinarius professor in the Chair for Theoretical Physics, at the

University of Zurich The University of Zurich (UZH, ) is a public university, public research university in Zurich, Switzerland. It is the largest university in Switzerland, with its 28,000 enrolled students. It was founded in 1833 from the existing colleges of the ...

, when he succeeded

Erwin Schrödinger Erwin Rudolf Josef Alexander Schrödinger ( ; ; 12 August 1887 – 4 January 1961), sometimes written as or , was an Austrian-Irish theoretical physicist who developed fundamental results in quantum field theory, quantum theory. In particul ...

, in 1928, the same year

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 ...

was appointed to the

ETH Zurich ETH Zurich (; ) is a public university in Zurich, Switzerland. Founded in 1854 with the stated mission to educate engineers and scientists, the university focuses primarily on science, technology, engineering, and mathematics. ETH Zurich ran ...

. 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, or UChi) is a Private university, private research university in Chicago, Illinois, United States. Its main campus is in the Hyde Park, Chicago, Hyde Park neighborhood on Chicago's South Side, Chic ...

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

Ascona 300px, Ascona Ascona ( ) 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 yearly Ascona Jazz Festival. ...

Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...

Research

In 1926, Wentzel,

, and

independently developed what became known as the

, also known as the ''

WKB approximation In mathematical physics, the WKB approximation or WKB method is a technique for finding approximate solutions to Linear differential equation, linear differential equations with spatially varying coefficients. It is typically used for a Semiclass ...

'', ''classical approach'', and ''phase integral method''. Wentzel is also known for his contributions to photoemission and scattering theory. Late career work includes contributions to the discussion of gauge invariant theories of superconductivity.

Awards and honors

In 1975, Wentzel 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 Friedrich Georg "Fritz" Houtermans (January 22, 1903 – March 1, 1966) was a Dutch-Austrian-German atomic and nuclear physicist and Communist born in Zoppot (now Sopot) near Danzig (now Gdańsk), West Prussia to a Dutch father, who was a wealt ...

. 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) is an American historian of physics. McCormmach grew up in Walla Walla, Washington and studied physics at Washington State University, Washington State College with bachelor's degree in 1955. As a Rho ...

. '' 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 (November 6, 1937, in Berlin – November 10, 2016, in Munich) was a German physicist and science historian. Biography Education Rechenberg studied mathematics, physics and astronomy at the University of Munich and graduat ...

. ''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 German quantum physicists Academic staff of the Ludwig Maximilian University of Munich Academic staff of Leipzig University Academic staff of the University of Zurich University of Chicago faculty University of Greifswald alumni Ludwig Maximilian University of Munich alumni German theoretical physicists German mathematical physicists Members of the United States National Academy of Sciences Winners of the Max Planck Medal