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Werner Karl Heisenberg (; ; 5 December 1901 – 1 February 1976) was a German
theoretical physicist Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain, and predict natural phenomena. This is in contrast to experimental physics, which uses experi ...
, one of the main pioneers of the theory 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 ...
and a principal scientist in the
German nuclear program during World War II Nazi Germany Nazi Germany, officially known as the German Reich and later the Greater German Reich, was the German Reich, German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transformin ...
. He published his ''Umdeutung'' paper in 1925, a major reinterpretation of
old quantum theory The old quantum theory is a collection of results from the years 1900–1925, which predate modern quantum mechanics. The theory was never complete or self-consistent, but was instead a set of heuristic corrections to classical mechanics. The th ...
. In the subsequent series of papers with
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
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 ...
, during the same year, his matrix formulation of quantum mechanics was substantially elaborated. He is known for the
uncertainty principle The uncertainty principle, also known as Heisenberg's indeterminacy principle, is a fundamental concept in quantum mechanics. It states that there is a limit to the precision with which certain pairs of physical properties, such as position a ...
, which he published in 1927. Heisenberg was awarded the 1932
Nobel Prize in Physics The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...
"for the creation of quantum mechanics". Heisenberg also made contributions to the theories of the
hydrodynamics In physics, physical chemistry and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids – liquids and gases. It has several subdisciplines, including (the study of air and other gases in ...
of
turbulent flow In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by Chaos theory, chaotic changes in pressure and flow velocity. It is in contrast to laminar flow, which occurs when a fluid flows in parallel layers with no disrupt ...
s, the
atomic nucleus The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford at the Department_of_Physics_and_Astronomy,_University_of_Manchester , University of Manchester ...
,
ferromagnetism Ferromagnetism is a property of certain materials (such as iron) that results in a significant, observable magnetic permeability, and in many cases, a significant magnetic coercivity, allowing the material to form a permanent magnet. Ferromagne ...
,
cosmic rays Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar ...
, and
subatomic particles In physics, a subatomic particle is a particle smaller than an atom. According to the Standard Model of particle physics, a subatomic particle can be either a composite particle, which is composed of other particles (for example, a baryon, like ...
. He introduced the concept of a
wave function collapse In various interpretations of quantum mechanics, wave function collapse, also called reduction of the state vector, occurs when a wave function—initially in a superposition of several eigenstates—reduces to a single eigenstate due to in ...
. He was also instrumental in planning the first West German
nuclear reactor A nuclear reactor is a device used to initiate and control a Nuclear fission, fission nuclear chain reaction. They are used for Nuclear power, commercial electricity, nuclear marine propulsion, marine propulsion, Weapons-grade plutonium, weapons ...
at
Karlsruhe Karlsruhe ( ; ; ; South Franconian German, South Franconian: ''Kallsruh'') is the List of cities in Baden-Württemberg by population, third-largest city of the States of Germany, German state of Baden-Württemberg, after its capital Stuttgart a ...
, together with a
research reactor Research reactors are nuclear fission-based nuclear reactors that serve primarily as a neutron source. They are also called non-power reactors, in contrast to power reactors that are used for electricity production, heat generation, or maritim ...
in
Munich Munich is the capital and most populous city of Bavaria, Germany. As of 30 November 2024, its population was 1,604,384, making it the third-largest city in Germany after Berlin and Hamburg. Munich is the largest city in Germany that is no ...
, in 1957. Following World War II, he was appointed director of the
Kaiser Wilhelm Institute for Physics The Kaiser Wilhelm Society for the Advancement of Science () was a German scientific institution established in the German Empire in 1911. Its functions were taken over by the Max Planck Society. The Kaiser Wilhelm Society was an umbrella organi ...
, which soon thereafter was renamed the
Max Planck Institute for Physics The Max Planck Institute for Physics (MPP) is a research institute located in Garching, near Munich, Germany. It specializes in high energy physics and astroparticle physics. The MPP is part of the Max Planck Society and is also known as the We ...
. He was director of the institute until it was moved to Munich in 1958. He then became director of the
Max Planck Institute for Physics and Astrophysics The Max Planck Institute for Physics and Astrophysics is a former institute of the Max Planck Society in Germany. Located in Munich, it was also known as the Werner Heisenberg Institute. The institute was founded in 1958 as a successor to the Max ...
from 1960 to 1970. Heisenberg was also president of the
German Research Council The German Research Foundation ( ; DFG ) is a German research funding organization, which functions as a self-governing institution for the promotion of science and research in the Federal Republic of Germany. In 2019, the DFG had a funding bud ...
, chairman of the Commission for Atomic Physics, chairman of the Nuclear Physics Working Group, and president of the
Alexander von Humboldt Foundation The Alexander von Humboldt Foundation () is a foundation that promotes international academic cooperation between scientists and scholars from Germany and abroad. Established by the government of the Federal Republic of Germany, it is funded by t ...
.


Early life and education


Early years

Werner Karl Heisenberg was born in
Würzburg Würzburg (; Main-Franconian: ) is, after Nuremberg and Fürth, the Franconia#Towns and cities, third-largest city in Franconia located in the north of Bavaria. Würzburg is the administrative seat of the Regierungsbezirk Lower Franconia. It sp ...
, Germany, to
Kaspar Ernst August Heisenberg Kaspar Ernst August Heisenberg (November13, 1869November22, 1930) was a German Byzantinist. His son was Werner Heisenberg. Heisenberg came from a Westphalian family of craftsmen. He was the son of Wilhelm August Heisenberg (1831–1912), a locksm ...
, and his wife, Annie Wecklein. His father was a secondary school teacher of
classical language According to the definition by George L. Hart, a classical language is any language with an independent literary tradition and a large body of ancient written literature. Classical languages are usually extinct languages. Those that are still ...
s who became Germany's only ''
ordentlicher Professor Academic ranks in Germany are the titles, relative importance and power of professors, researchers, and administrative personnel held in academia. Overview Appointment grades * (Pay grade: ''W3'' or ''W2'') * (''W3'') * (''W2'') * (''W2'', ...
'' (ordinarius professor) of medieval and
modern Greek Modern Greek (, or , ), generally referred to by speakers simply as Greek (, ), refers collectively to the dialects of the Greek language spoken in the modern era, including the official standardized form of the language sometimes referred to ...
studies in the university system. Heisenberg was raised and lived as a
Lutheran Lutheranism is a major branch of Protestantism that emerged under the work of Martin Luther, the 16th-century German friar and Protestant Reformers, reformer whose efforts to reform the theology and practices of the Catholic Church launched ...
Christian. In his late teenage years, Heisenberg read Plato's '' Timaeus'' while hiking in the
Bavarian Alps The Bavarian Alps (, ) is a collective name for several mountain ranges of the Northern Limestone Alps within the German state of Bavaria. Geography The term in its wider sense refers to that part of the Eastern Alps that lies on Bavarian state ...
. He recounted philosophical conversations with his fellow students and teachers about understanding the
atom Atoms are the basic particles of the chemical elements. An atom consists of a atomic nucleus, nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished fr ...
while receiving his scientific training in Munich, Göttingen and Copenhagen. Heisenberg later stated that "My mind was formed by studying philosophy, Plato and that sort of thing" and that "Modern physics has definitely decided in favor of Plato. In fact the smallest units of matter are not physical objects in the ordinary sense; they are forms, ideas which can be expressed unambiguously only in mathematical language". In 1919 Heisenberg arrived in Munich as a member of the ''
Freikorps (, "Free Corps" or "Volunteer Corps") were irregular German and other European paramilitary volunteer units that existed from the 18th to the early 20th centuries. They effectively fought as mercenaries or private military companies, rega ...
'' to fight the
Bavarian Soviet Republic The Bavarian Soviet Republic (or Bavarian Council Republic), also known as the Munich Soviet Republic (), was a short-lived unrecognised socialist state in Bavaria during the German revolution of 1918–1919. A group of communists and anarchist ...
established a year earlier. Five decades later he recalled those days as youthful fun, like "playing cops and robbers and so on; it was nothing serious at all"; his duties were restricted to "seizing bicycles or typewriters from 'red' administrative buildings", and guarding suspected "red" prisoners.


University studies

From 1920 to 1923, he studied physics and mathematics at 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 ...
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 ...
and
Wilhelm Wien Wilhelm Carl Werner Otto Fritz Franz Wien (; 13 January 1864 – 30 August 1928) was a German physicist who used theories about heat and electromagnetism to deduce Wien's displacement law, which calculates the emission of a blackbody at any te ...
and at the Georg-August University of Göttingen with
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
James Franck James Franck (; 26 August 1882 – 21 May 1964) was a German-American physicist who received the 1925 Nobel Prize in Physics with Gustav Hertz "for their discovery of the laws governing the impact of an electron upon an atom". He completed hi ...
and mathematics with
David Hilbert David Hilbert (; ; 23 January 1862 – 14 February 1943) was a German mathematician and philosopher of mathematics and one of the most influential mathematicians of his time. Hilbert discovered and developed a broad range of fundamental idea ...
. He received his doctorate in 1923 at Munich under Sommerfeld. In June 1922, Sommerfeld took Heisenberg to Göttingen to attend the Bohr Festival, because Sommerfeld had a sincere interest in his students and knew of Heisenberg's interest in
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 ...
's theories 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 ...
. At the event, Bohr was a guest lecturer and gave a series of comprehensive lectures on quantum atomic physics and Heisenberg met Bohr for the first time, which had a lasting effect on him. Heisenberg's
doctoral thesis A thesis (: theses), or dissertation (abbreviated diss.), is a document submitted in support of candidature for an academic degree or professional qualification presenting the author's research and findings.International Standard ISO 7144: D ...
, the topic of which was suggested by Sommerfeld, was on
turbulence In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to laminar flow, which occurs when a fluid flows in parallel layers with no disruption between ...
; the thesis discussed both the stability of
laminar flow Laminar flow () is the property of fluid particles in fluid dynamics to follow smooth paths in layers, with each layer moving smoothly past the adjacent layers with little or no mixing. At low velocities, the fluid tends to flow without lateral m ...
and the nature of
turbulent flow In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by Chaos theory, chaotic changes in pressure and flow velocity. It is in contrast to laminar flow, which occurs when a fluid flows in parallel layers with no disrupt ...
. The problem of stability was investigated by the use of the
Orr–Sommerfeld equation The Orr–Sommerfeld equation, in fluid dynamics, is an eigenvalue equation describing the linear two-dimensional modes of disturbance to a viscous parallel flow. The solution to the Navier–Stokes equations for a parallel, laminar flow can become ...
, a fourth-order
linear differential equation In mathematics, a linear differential equation is a differential equation that is linear equation, linear in the unknown function and its derivatives, so it can be written in the form a_0(x)y + a_1(x)y' + a_2(x)y'' \cdots + a_n(x)y^ = b(x) wher ...
for small disturbances from laminar flow. He briefly returned to this topic after World War II. At Göttingen, under Born, 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 ...
in 1924 with a ''Habilitationsschrift'' (habilitation thesis) on the anomalous
Zeeman effect The Zeeman effect () is the splitting of a spectral line into several components in the presence of a static magnetic field. It is caused by the interaction of the magnetic field with the magnetic moment of the atomic electron associated with ...
.
Werner Heisenberg Biography
'', ''Nobel Prize in Physics 1932'' Nobelprize.org.
; see the entry for Heisenberg. In his youth he was a member and Scoutleader of the ''Neupfadfinder'', a German Scout association and part of the
German Youth Movement The German Youth Movement () is a collective term for a cultural and educational movement that started in 1896. It consists of numerous associations of young people that focus on outdoor activities. The movement included German Scouting and the ...
. In August 1923 Robert Honsell and Heisenberg organized a trip to Finland with a Scout group of this association from Munich.


Personal life

Heisenberg enjoyed
classical music Classical music generally refers to the art music of the Western world, considered to be #Relationship to other music traditions, distinct from Western folk music or popular music traditions. It is sometimes distinguished as Western classical mu ...
and was an accomplished pianist, and playing for others was a large part of his social life. During the early 1930s he would often play music and dance at the Berlin home of his aristocratic student
Carl Friedrich von Weizsäcker Carl Friedrich Freiherr von Weizsäcker (; 28 June 1912 – 28 April 2007) was a German physicist and philosopher. He was the longest-living member of the team which performed nuclear research in Nazi Germany during the Second World War, un ...
, during which time he carried on a courtship with Carl's high-school-age sister Adelheid, which scandalized her parents and led to him being unwelcome at their home for a time. Years later his interest in music also led to meeting his future wife. In January 1937, Heisenberg met Elisabeth Schumacher (1914–1998) at a private music recital. Elisabeth was the daughter of a well-known Berlin economics professor, and her brother was the economist
E. F. Schumacher Ernst Friedrich Schumacher (16 August 1911 – 4 September 1977) was a German-born British statistician and economist who is best known for his proposals for human-scale, decentralised and appropriate technologies.Biography on the inner dust ...
, author of ''
Small Is Beautiful ''Small Is Beautiful: A Study of Economics As If People Mattered'' is a collection of essays published in 1973 by German-born British economist E. F. Schumacher. The title "Small Is Beautiful" came from a principle espoused by Schumache ...
''. Heisenberg married her on 29 April. Fraternal twins Maria and Wolfgang were born in January 1938, whereupon
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 ...
congratulated Heisenberg on his "pair creation"a wordplay on a process from elementary particle physics,
pair production Pair production is the creation of a subatomic particle and its antiparticle from a neutral boson. Examples include creating an electron and a positron, a muon and an antimuon, or a proton and an antiproton. Pair production often refers ...
. They had five more children over the next 12 years: Barbara, Christine, Jochen,
Martin Martin may refer to: Places Antarctica * Martin Peninsula, Marie Byrd Land * Port Martin, Adelie Land * Point Martin, South Orkney Islands Europe * Martin, Croatia, a village * Martin, Slovakia, a city * Martín del Río, Aragón, Spain * M ...
and Verena. In 1939 he bought a summer home for his family in
Urfeld am Walchensee Urfeld am Walchensee is a village in the municipality of Kochel am See in the district of Bad Tölz-Wolfratshausen in Bavaria, Germany. It lies on the northwest shore of Lake Walchensee.Gudelius, Jost: ''Die Jachenau''. Jachenau 2008, , S. 139 Fam ...
, in southern Germany. One of Heisenberg's sons, Martin Heisenberg, became a
neurobiologist A neuroscientist (or neurobiologist) is a scientist specializing in neuroscience that deals with the anatomy and function of neurons, neural circuits, and glia, and their behavioral, biological, and psychological roles in health and disease. ...
at the
University of Würzburg The Julius Maximilian University of Würzburg (also referred to as the University of Würzburg, in German ''Julius-Maximilians-Universität Würzburg'') is a public research university in Würzburg, Germany. Founded in 1402, it is one of the ol ...
, while another son,
Jochen Heisenberg Jochen Heisenberg (born 16 May 1939) is a German physicist specializing in nuclear physics, and Professor Emeritus of Physics at the University of New Hampshire. He is the son of Nobel Prize-winning physicist Werner Heisenberg, who was a co-foun ...
, became a physics professor at the
University of New Hampshire The University of New Hampshire (UNH) is a Public university, public Land-grant university, land-grant research university with its main campus in Durham, New Hampshire, United States. It was founded and incorporated in 1866 as a land grant coll ...
.


Academic career


Göttingen, Copenhagen and Leipzig

From 1924 to 1927, Heisenberg was 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 ...
at
Göttingen Göttingen (, ; ; ) is a college town, university city in Lower Saxony, central Germany, the Capital (political), capital of Göttingen (district), the eponymous district. The River Leine runs through it. According to the 2022 German census, t ...
, meaning he was qualified to teach and examine independently, without having a chair. From 17 September 1924 to 1 May 1925, under an International Education Board
Rockefeller Foundation The Rockefeller Foundation is an American private foundation and philanthropic medical research and arts funding organization based at 420 Fifth Avenue, New York City. The foundation was created by Standard Oil magnate John D. Rockefeller (" ...
fellowship, Heisenberg went to do research with
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 ...
, director of the Institute of Theoretical Physics at the
University of Copenhagen The University of Copenhagen (, KU) is a public university, public research university in Copenhagen, Copenhagen, Denmark. Founded in 1479, the University of Copenhagen is the second-oldest university in Scandinavia, after Uppsala University. ...
. On June 7, after weeks of failing to alleviate a severe bout of
hay fever Allergic rhinitis, of which the seasonal type is called hay fever, is a type of rhinitis, inflammation in the nose that occurs when the immune system overreacts to allergens in the air. It is classified as a Allergy, type I hypersensitivity re ...
with aspirin and cocaine, Heisenberg retreated to the pollen-free
North Sea The North Sea lies between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France. A sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Se ...
island of
Helgoland Heligoland (; , ; Heligolandic Frisian: , , Mooring Frisian: , ) is a small archipelago in the North Sea. The islands were historically possessions of Denmark, then became possessions of the United Kingdom from 1807 to 1890. Since 1890, the ...
to focus on quantum mechanics. His seminal paper, "
Über quantentheoretische Umdeutung kinematischer und mechanischer Beziehungen In the history of physics, "On the quantum-theoretical reinterpretation of kinematical and mechanical relationships" (), also known as the ''Umdeutung'' (reinterpretation) paper, was a breakthrough article in quantum mechanics written by Werner H ...
" ("Quantum theoretical re-interpretation of kinematic and mechanical relations") also called the ''Umdeutung'' (reinterpretation) paper, was published in September 1925. He returned to Göttingen and, with
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
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 ...
over a period of about six months, developed the
matrix mechanics Matrix mechanics is a formulation of quantum mechanics created by Werner Heisenberg, Max Born, and Pascual Jordan in 1925. It was the first conceptually autonomous and logically consistent formulation of quantum mechanics. Its account of quantum ...
formulation 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 ...
. On 1 May 1926, Heisenberg began his appointment as a university lecturer and assistant to Bohr in Copenhagen. It was in Copenhagen, in 1927, that Heisenberg developed his
uncertainty principle The uncertainty principle, also known as Heisenberg's indeterminacy principle, is a fundamental concept in quantum mechanics. It states that there is a limit to the precision with which certain pairs of physical properties, such as position a ...
, while working on the mathematical foundations of quantum mechanics. On 23 February, Heisenberg wrote a letter to fellow physicist
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 ...
, in which he first described his new principle. In his paper on the principle, Heisenberg used the word "''Ungenauigkeit''" (imprecision), not uncertainty, to describe it. In 1927, Heisenberg was appointed ''ordentlicher Professor'' (professor ordinarius) of theoretical physics and head of the department of physics at 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 ...
; he gave his inaugural lecture there on 1 February 1928. In his first paper published from Leipzig, Heisenberg used the
Pauli exclusion principle In quantum mechanics, the Pauli exclusion principle (German: Pauli-Ausschlussprinzip) states that two or more identical particles with half-integer spins (i.e. fermions) cannot simultaneously occupy the same quantum state within a system that o ...
to solve the mystery of
ferromagnetism Ferromagnetism is a property of certain materials (such as iron) that results in a significant, observable magnetic permeability, and in many cases, a significant magnetic coercivity, allowing the material to form a permanent magnet. Ferromagne ...
. At 25 years old, Heisenberg gained the title of the youngest full-time professor in Germany and professorial chair of the Institute for Theoretical Physics at the University of Leipzig. He gave lectures that were attended by physicists like
Edward Teller Edward Teller (; January 15, 1908 – September 9, 2003) was a Hungarian and American Theoretical physics, theoretical physicist and chemical engineer who is known colloquially as "the father of the hydrogen bomb" and one of the creators of ...
and
Robert Oppenheimer J. Robert Oppenheimer (born Julius Robert Oppenheimer ; April 22, 1904 – February 18, 1967) was an American theoretical physicist who served as the director of the Manhattan Project's Los Alamos Laboratory during World War II. He is often ...
, who would later work on the
Manhattan Project The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada. From 1942 to 1946, the ...
for the United States. During Heisenberg's tenure at Leipzig, the high quality of the doctoral students and
post-graduate Postgraduate education, graduate education, or graduate school consists of academic or professional degrees, certificates, diplomas, or other qualifications usually pursued by post-secondary students who have earned an undergraduate (bachelor' ...
and research associates who studied and worked with him is clear from the acclaim that many later earned. They included Erich Bagge,
Felix Bloch Felix Bloch (; ; 23 October 1905 – 10 September 1983) was a Swiss-American physicist who shared the 1952 Nobel Prize in Physics with Edward Mills Purcell "for their development of new methods for nuclear magnetic precision measurements and di ...
,
Ugo Fano Ugo Fano (July 28, 1912 – February 13, 2001) was an Italian American physicist, notable for contributions to theoretical physics. Biography Ugo Fano was born into a wealthy Jewish family in Turin, Italy. His father was Gino Fano, a professo ...
,
Siegfried Flügge Siegfried Flügge (16 March 1912, in Dresden – 15 December 1997, in Hinterzarten) was a German theoretical physicist who made contributions to nuclear physics and the theoretical basis for nuclear weapons. He worked on the German nuclear ene ...
, William Vermillion Houston,
Friedrich Hund Friedrich Hermann Hund (4 February 1896 – 31 March 1997) was a German physicist from Karlsruhe known for his work on atoms and molecules. He is known for the Hund's rules to predict the electron configuration of chemical elements. His work on H ...
,
Robert S. Mulliken Robert Sanderson Mulliken Note Longuet-Higgins' amusing title "Selected ploddings of Robert S Mulliken" for reference B238 1965 on page 354 of this Biographical Memoir. The title should be "Selected papers of Robert S Mulliken." (June 7, 1896 ...
,
Rudolf Peierls Sir Rudolf Ernst Peierls, (; ; 5 June 1907 – 19 September 1995) was a German-born British physicist who played a major role in Tube Alloys, Britain's nuclear weapon programme, as well as the subsequent Manhattan Project, the combined Allied ...
,
George Placzek George Placzek (; September 26, 1905 – October 9, 1955) was a Czech physicist. His work involved a fundamental theory of Raman scattering, molecular spectroscopy in gases and liquids, neutron physics and mathematical physics. Together with Ot ...
,
Isidor Isaac Rabi Israel Isidor Isaac Rabi (; ; July 29, 1898 – January 11, 1988) was an American nuclear physicist who received the Nobel Prize in Physics in 1944 for his discovery of nuclear magnetic resonance, which is used in magnetic resonance imaging. H ...
,
Fritz Sauter Fritz Eduard Josef Maria Sauter (; 9 June 1906 – 24 May 1983) was an Austrian-German physicist who worked mostly in quantum electrodynamics and solid-state physics. Education From 1924 to 1928, Sauter studied mathematics and physics at the L ...
, John C. Slater,
Edward Teller Edward Teller (; January 15, 1908 – September 9, 2003) was a Hungarian and American Theoretical physics, theoretical physicist and chemical engineer who is known colloquially as "the father of the hydrogen bomb" and one of the creators of ...
,
John Hasbrouck van Vleck John Hasbrouck Van Vleck (; March 13, 1899 – October 27, 1980) was an American physicist and mathematician. He was co-awarded the Nobel Prize in Physics in 1977, for his contributions to the understanding of the behavior of electronic magnetis ...
,
Victor Frederick Weisskopf Victor Frederick "Viki" Weisskopf (also spelled Viktor; September 19, 1908 – April 22, 2002) was an Austrian-born American theoretical physicist. He did postdoctoral work with Werner Heisenberg, Erwin Schrödinger, Wolfgang Pauli, and Niels ...
,
Carl Friedrich von Weizsäcker Carl Friedrich Freiherr von Weizsäcker (; 28 June 1912 – 28 April 2007) was a German physicist and philosopher. He was the longest-living member of the team which performed nuclear research in Nazi Germany during the Second World War, un ...
,
Gregor Wentzel Gregor Wentzel (17 February 1898 – 12 August 1978) was a German physicist known for development of quantum mechanics. Wentzel, Hendrik Kramers, and Léon Brillouin developed the Wentzel–Kramers–Brillouin approximation in 1926. In his early y ...
, and
Clarence Zener Clarence Melvin Zener ( ; December 1, 1905 – July 2, 1993) was an American physicist who in 1934 was the first to describe the property concerning the breakdown of electrical insulators. These findings were later exploited by Bell Labs in the ...
. In early 1929, Heisenberg and Pauli submitted the first of two papers laying the foundation for relativistic
quantum field theory In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines Field theory (physics), field theory and the principle of relativity with ideas behind quantum mechanics. QFT is used in particle physics to construct phy ...
. Also in 1929, Heisenberg went on a lecture tour of China, Japan, India, and the United States. In the spring of 1929, he was a visiting lecturer 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 ...
, where he lectured on quantum mechanics. In 1928, the British
mathematical physicist Mathematical physics is the development of mathematical methods for application to problems in physics. The ''Journal of Mathematical Physics'' defines the field as "the application of mathematics to problems in physics and the development of ...
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 ...
had derived his
relativistic wave equation In physics, specifically relativistic quantum mechanics (RQM) and its applications to particle physics, relativistic wave equations predict the behavior of particles at high energies and velocities comparable to the speed of light. In the c ...
of quantum mechanics, which implied the existence of positive electrons, later to be named
positron The positron or antielectron is the particle with an electric charge of +1''elementary charge, e'', a Spin (physics), spin of 1/2 (the same as the electron), and the same Electron rest mass, mass as an electron. It is the antiparticle (antimatt ...
s. In 1932, from a
cloud chamber A cloud chamber, also known as a Wilson chamber, is a particle detector used for visualizing the passage of ionizing radiation. A cloud chamber consists of a sealed environment containing a supersaturated vapor of water or alcohol. An energetic ...
photograph of
cosmic ray Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the ...
s, the American physicist
Carl David Anderson Carl David Anderson (September 3, 1905 – January 11, 1991) was an American particle physicist who shared the 1936 Nobel Prize in Physics with Victor Francis Hess for his discovery of the positron. Biography Anderson was born in New York Cit ...
identified a track as having been made by a
positron The positron or antielectron is the particle with an electric charge of +1''elementary charge, e'', a Spin (physics), spin of 1/2 (the same as the electron), and the same Electron rest mass, mass as an electron. It is the antiparticle (antimatt ...
. In mid-1933, Heisenberg presented his theory of the positron. His thinking on Dirac's theory and further development of the theory were set forth in two papers. The first, "Bemerkungen zur Diracschen Theorie des Positrons" ("Remarks on Dirac's theory of the positron") was published in 1934, and the second, "Folgerungen aus der Diracschen Theorie des Positrons" ("Consequences of Dirac's Theory of the Positron"), was published in 1936. In these papers Heisenberg was the first to reinterpret the
Dirac equation In particle physics, the Dirac equation is a relativistic wave equation derived by British physicist Paul Dirac in 1928. In its free form, or including electromagnetic interactions, it describes all spin-1/2 massive particles, called "Dirac ...
as a "classical"
field equation In theoretical physics and applied mathematics, a field equation is a partial differential equation which determines the dynamics of a physical field, specifically the time evolution and spatial distribution of the field. The solutions to the equa ...
for any point particle of
spin Spin or spinning most often refers to: * Spin (physics) or particle spin, a fundamental property of elementary particles * Spin quantum number, a number which defines the value of a particle's spin * Spinning (textiles), the creation of yarn or thr ...
ħ/2, itself subject to quantization conditions involving anti-
commutator In mathematics, the commutator gives an indication of the extent to which a certain binary operation fails to be commutative. There are different definitions used in group theory and ring theory. Group theory The commutator of two elements, ...
s. Thus reinterpreting it as a (quantum) field equation accurately describing electrons, Heisenberg put matter on the same footing as
electromagnetism In physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interacti ...
: as being described by relativistic quantum field equations which allowed the possibility of particle creation and destruction. (
Hermann Weyl Hermann Klaus Hugo Weyl (; ; 9 November 1885 – 8 December 1955) was a German mathematician, theoretical physicist, logician and philosopher. Although much of his working life was spent in Zürich, Switzerland, and then Princeton, New Jersey, ...
had already described this in a 1929 letter to
Albert Einstein Albert Einstein (14 March 187918 April 1955) was a German-born theoretical physicist who is best known for developing the theory of relativity. Einstein also made important contributions to quantum mechanics. His mass–energy equivalence f ...
.)


Matrix mechanics and the Nobel Prize

Heisenberg's ''Umdeutung'' paper that established modern quantum mechanics has puzzled physicists and historians. His methods assume that the reader is familiar with Kramers-Heisenberg transition probability calculations. The main new idea, non-commuting matrices, is justified only by a rejection of unobservable quantities. It introduces the non-
commutative In mathematics, a binary operation is commutative if changing the order of the operands does not change the result. It is a fundamental property of many binary operations, and many mathematical proofs depend on it. Perhaps most familiar as a pr ...
multiplication of
matrices Matrix (: matrices or matrixes) or MATRIX may refer to: Science and mathematics * Matrix (mathematics), a rectangular array of numbers, symbols or expressions * Matrix (logic), part of a formula in prenex normal form * Matrix (biology), the ...
by physical reasoning, based on the
correspondence principle In physics, a correspondence principle is any one of several premises or assertions about the relationship between classical and quantum mechanics. The physicist Niels Bohr coined the term in 1920 during the early development of quantum theory; ...
, despite the fact that Heisenberg was not then familiar with the mathematical theory of matrices. The path leading to these results has been reconstructed by MacKinnon, and the detailed calculations are worked out by Aitchison and coauthors. In Copenhagen, Heisenberg and
Hans 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 statistica ...
collaborated on a paper on dispersion, or the scattering from atoms of radiation whose wavelength is larger than the atoms. They showed that the successful formula Kramers had developed earlier could not be based on Bohr orbits, because the transition frequencies are based on level spacings which are not constant. The frequencies which occur in the
Fourier transform In mathematics, the Fourier transform (FT) is an integral transform that takes a function as input then outputs another function that describes the extent to which various frequencies are present in the original function. The output of the tr ...
of the classical
sharp series The sharp series is a series of spectral lines in the atomic emission spectrum caused when electrons descend from higher-energy s orbitals of an atom to the lowest available p orbital. The spectral lines include some in the visible light, and they ...
orbits, by contrast, are equally spaced. But these results could be explained by a semi-classical
virtual state In quantum physics, a virtual state is a very short-lived, unobservable quantum state. In many quantum processes a virtual state is an intermediate state, sometimes described as "imaginary" in a multi-step process that mediates otherwise forb ...
model: the incoming radiation excites the valence, or outer, electron to a virtual state from which it decays. In a subsequent paper, Heisenberg showed that this virtual oscillator model could also explain the polarization of fluorescent radiation. These two successes, and the continuing failure of the
Bohr–Sommerfeld model The Bohr–Sommerfeld model (also known as the Sommerfeld model or Bohr–Sommerfeld theory) was an extension of the Bohr model to allow elliptical orbits of electrons around an atomic nucleus. Bohr–Sommerfeld theory is named after Danis ...
to explain the outstanding problem of the anomalous Zeeman effect, led Heisenberg to use the virtual oscillator model to try to calculate spectral frequencies. The method proved too difficult to immediately apply to realistic problems, so Heisenberg turned to a simpler example, the
anharmonic oscillator In classical mechanics, anharmonicity is the deviation of a system from being a harmonic oscillator. An oscillator that is not oscillating in harmonic motion is known as an anharmonic oscillator where the system can be approximated to a harmo ...
. The dipole oscillator consists of a
simple harmonic oscillator In mechanics and physics, simple harmonic motion (sometimes abbreviated as ) is a special type of periodic function, periodic motion an object experiences by means of a restoring force whose magnitude is directly proportionality (mathematics), ...
, which is thought of as a
charged particle In physics, a charged particle is a particle with an electric charge. For example, some elementary particles, like the electron or quarks are charged. Some composite particles like protons are charged particles. An ion, such as a molecule or atom ...
on a spring, perturbed by an external force, like an external charge. The motion of the oscillating charge can be expressed as a
Fourier series A Fourier series () is an Series expansion, expansion of a periodic function into a sum of trigonometric functions. The Fourier series is an example of a trigonometric series. By expressing a function as a sum of sines and cosines, many problems ...
in the frequency of the oscillator. Heisenberg solved for the quantum behavior by two different methods. First, he treated the system with the virtual oscillator method, calculating the transitions between the levels that would be produced by the external source. He then solved the same problem by treating the anharmonic potential term as a perturbation to the harmonic oscillator and using the
perturbation methods In mathematics and applied mathematics, perturbation theory comprises methods for finding an approximate solution to a problem, by starting from the exact solution of a related, simpler problem. A critical feature of the technique is a middle ...
that he and Born had developed. Both methods led to the same results for the first and the very complicated second-order correction terms. This suggested that behind the very complicated calculations lay a consistent scheme. So Heisenberg set out to formulate these results without any explicit dependence on the virtual oscillator model. To do this, he replaced the Fourier expansions for the spatial coordinates with matrices, matrices which corresponded to the transition coefficients in the virtual oscillator method. He justified this replacement by an appeal to Bohr's correspondence principle and the Pauli doctrine that quantum mechanics must be limited to observables. On 9 July, Heisenberg gave Born this paper to review and submit for publication. When Born read the paper, he recognized the formulation as one which could be transcribed and extended to the systematic language of matrices, which he had learned from his study under
Jakob Rosanes Jakob Rosanes (also Jacob; 16 August 1842 – 6 January 1922) was a German mathematician who worked on algebraic geometry and invariant theory. He was also a chess master. Life and career Rosanes was a grandson of Rabbi Akiva Eiger, one of th ...
at Breslau University. Born, with the help of his assistant and former student
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 ...
, began immediately to make the transcription and extension, and they submitted their results for publication; the paper was received for publication just 60 days after Heisenberg's paper. A follow-on paper was submitted for publication before the end of the year by all three authors. Up until this time, matrices were seldom used by physicists; they were considered to belong to the realm of
pure mathematics Pure mathematics is the study of mathematical concepts independently of any application outside mathematics. These concepts may originate in real-world concerns, and the results obtained may later turn out to be useful for practical applications ...
.
Gustav Mie Gustav Adolf Feodor Wilhelm Ludwig Mie (; 29 September 1868 – 13 February 1957) was a German physicist. His work included Mie scattering, the Mie potential, the Mie–Grüneisen equation of state and an early effort at classical unified field ...
had used them in a paper on electrodynamics in 1912 and Born had used them in his work on the lattice theory of crystals in 1921. While matrices were used in these cases, the algebra of matrices with their multiplication did not enter the picture as they did in the matrix formulation of quantum mechanics. In 1928, Albert Einstein nominated Heisenberg, Born, and Jordan for the
Nobel Prize in Physics The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...
. The announcement of the Nobel Prize in Physics for 1932 was delayed until November 1933. It was at that time announced that Heisenberg had won the Prize for 1932 "for the creation of quantum mechanics, the application of which has, inter alia, led to the discovery of the allotropic forms of hydrogen".The Nobel Prize in Physics 1932
. Nobelprize.org. Retrieved on 1 February 2012.
Nobel Prize in Physics The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...
an
1933
 – Nobel Prize Presentation Speech.


Interpretation of quantum theory

The development of quantum mechanics, and the apparently contradictory implications in regard to what is "real" had profound philosophical implications, including what scientific observations truly mean. In contrast to Albert Einstein and
Louis de Broglie Louis Victor Pierre Raymond, 7th Duc de Broglie (15 August 1892 – 19 March 1987) was a French theoretical physicist and aristocrat known for his contributions to quantum theory. In his 1924 PhD thesis, he postulated the wave nature of elec ...
, who were realists who believed that particles had an objectively true momentum and position at all times (even if both could not be measured), Heisenberg was an anti-realist, arguing that direct knowledge of what is "real" was beyond the scope of science. In his book ''The Physicist's Conception of Nature'', Heisenberg argued that ultimately we only can speak of the ''knowledge'' (numbers in tables) which describes something about particles but we can never have any "true" access to the particles themselves:
We can no longer speak of the behaviour of the particle independently of the process of observation. As a final consequence, the natural laws formulated mathematically in quantum theory no longer deal with the elementary particles themselves but with our knowledge of them. Nor is it any longer possible to ask whether or not these particles exist in space and time objectively ... When we speak of the picture of nature in the exact science of our age, we do not mean a picture of nature so much as a ''picture of our relationships with nature''. ...Science no longer confronts nature as an objective observer, but sees itself as an actor in this interplay between man and nature. The scientific method of analysing, explaining and classifying has become conscious of its limitations, which arise out of the fact that by its intervention science alters and refashions the object of investigation. In other words, method and object can no longer be separated.


''SS'' investigation

Shortly after the discovery of the
neutron The neutron is a subatomic particle, symbol or , that has no electric charge, and a mass slightly greater than that of a proton. The Discovery of the neutron, neutron was discovered by James Chadwick in 1932, leading to the discovery of nucle ...
by
James Chadwick Sir James Chadwick (20 October 1891 – 24 July 1974) was an English nuclear physicist who received the Nobel Prize in Physics in 1935 for his discovery of the neutron. In 1941, he wrote the final draft of the MAUD Report, which inspired t ...
in 1932, Heisenberg submitted the first of three papers on his neutron-proton model of the nucleus. After
Adolf Hitler Adolf Hitler (20 April 1889 – 30 April 1945) was an Austrian-born German politician who was the dictator of Nazi Germany from 1933 until Death of Adolf Hitler, his suicide in 1945. Adolf Hitler's rise to power, He rose to power as the lea ...
came to power in 1933, Heisenberg was attacked in the press as a "White Jew" (i.e. an
Aryan ''Aryan'' (), or ''Arya'' (borrowed from Sanskrit ''ārya''), Oxford English Dictionary Online 2024, s.v. ''Aryan'' (adj. & n.); ''Arya'' (n.)''.'' is a term originating from the ethno-cultural self-designation of the Indo-Iranians. It stood ...
who acts like a Jew). Supporters of ''
Deutsche Physik ''Deutsche Physik'' (, "German Physics") or Aryan Physics () was a nationalist movement in the German physics community in the early 1930s which had the support of many eminent physicists in Germany. The term appears in the title of a four- ...
'', or German Physics (also known as Aryan Physics), launched vicious attacks against leading theoretical physicists, including Arnold Sommerfeld and Heisenberg. From the early 1930s onward, the
anti-Semitic Antisemitism or Jew-hatred is hostility to, prejudice towards, or discrimination against Jews. A person who harbours it is called an antisemite. Whether antisemitism is considered a form of racism depends on the school of thought. Antisemi ...
and anti-theoretical physics movement ''Deutsche Physik'' had concerned itself with quantum mechanics and the
theory of relativity The theory of relativity usually encompasses two interrelated physics theories by Albert Einstein: special relativity and general relativity, proposed and published in 1905 and 1915, respectively. Special relativity applies to all physical ph ...
. As applied in the university environment, political factors took priority over scholarly ability, even though its two most prominent supporters were the
Nobel Laureates in Physics The Nobel Prize in Physics () is awarded annually by the Royal Swedish Academy of Sciences to scientists in the various fields of physics. It is one of the five Nobel Prizes established by the 1895 will and testament, will of Alfred Nobel (wh ...
Philipp Lenard Philipp Eduard Anton von Lenard (; ; 7 June 1862 – 20 May 1947) was a Hungarian-German physicist who received the Nobel Prize in Physics in 1905 "for his work on cathode rays" and the discovery of many of their properties. One of his most im ...
and
Johannes Stark Johannes Stark (; 15 April 1874 – 21 June 1957) was a German physicist who received the Nobel Prize in Physics in 1919 "for his discovery of the Doppler effect in canal rays and the splitting of spectral lines in electric fields". This phenom ...
. There had been many failed attempts to have Heisenberg appointed as a professor at a number of German universities. His attempt to be appointed as successor to Arnold Sommerfeld failed because of opposition by the ''Deutsche Physik'' movement. On 1 April 1935, the eminent theoretical physicist Sommerfeld, Heisenberg's doctoral advisor at the
Ludwig-Maximilians-Universität München 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 ...
, achieved
emeritus ''Emeritus/Emerita'' () is an honorary title granted to someone who retires from a position of distinction, most commonly an academic faculty position, but is allowed to continue using the previous title, as in "professor emeritus". In some c ...
status. However, Sommerfeld stayed in his chair during the selection process for his successor, which took until 1 December 1939. The process was lengthy due to academic and political differences between the Munich Faculty's selection and that of the Reich Education Ministry and the supporters of ''Deutsche Physik''. In 1935, the Munich Faculty drew up a list of candidates to replace Sommerfeld as ordinarius professor of theoretical physics and head of the Institute for Theoretical Physics at the University of Munich. The three candidates had all been former students of Sommerfeld: Heisenberg, who had received the
Nobel Prize in Physics The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...
;
Peter Debye Peter Joseph William Debye ( ; born Petrus Josephus Wilhelmus Debije, ; March 24, 1884 – November 2, 1966) was a Dutch-American physicist and physical chemist, and Nobel laureate in Chemistry. Biography Early life Born in Maastricht, Neth ...
, who had received the
Nobel Prize in Chemistry The Nobel Prize in Chemistry () is awarded annually by the Royal Swedish Academy of Sciences to scientists in the various fields of chemistry. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895, awarded for outst ...
in 1936; and Richard Becker. The Munich Faculty was firmly behind these candidates, with Heisenberg as their first choice. However, supporters of ''Deutsche Physik'' and elements in the REM had their own list of candidates, and the battle dragged on for over four years. During this time, Heisenberg came under vicious attack by the ''Deutsche Physik'' supporters. One attack was published in ''
Das Schwarze Korps ''Das Schwarze Korps'' (; German for "The Black Corps") was the official newspaper of the ''Schutzstaffel'' (SS). This newspaper was published on Wednesdays and distributed free of charge. All SS members were encouraged to read it. The chief edi ...
'', the newspaper of the '' SS'', headed by
Heinrich Himmler Heinrich Luitpold Himmler (; 7 October 1900 – 23 May 1945) was a German Nazism, Nazi politician and military leader who was the 4th of the (Protection Squadron; SS), a leading member of the Nazi Party, and one of the most powerful p ...
. In this, Heisenberg was called a "White Jew" who should be made to "disappear". These attacks were taken seriously, as Jews were violently attacked and incarcerated. Heisenberg fought back with an editorial and a letter to Himmler, in an attempt to resolve the matter and regain his honour. At one point, Heisenberg's mother visited Himmler's mother. The two women knew each other, as Heisenberg's maternal grandfather and Himmler's father were rectors and members of a Bavarian hiking club. Eventually, Himmler settled the Heisenberg affair by sending two letters, one to SS
Gruppenführer __NOTOC__ ''Gruppenführer'' (, ) was an early paramilitary rank of the Nazi Party (NSDAP), first created in 1925 as a senior rank of the SA. Since then, the term ''Gruppenführer'' is also used for leaders of groups/teams of the police, fire d ...
Reinhard Heydrich Reinhard Tristan Eugen Heydrich ( , ; 7 March 1904 – 4 June 1942) was a German high-ranking SS and police official during the Nazi era and a principal architect of the Holocaust. He held the rank of SS-. Many historians regard Heydrich ...
and one to Heisenberg, both on 21 July 1938. In the letter to Heydrich, Himmler said Germany could not afford to lose or silence Heisenberg, as he would be useful for teaching a generation of scientists. To Heisenberg, Himmler said the letter came on the recommendation of his family and he cautioned Heisenberg to make a distinction between professional physics research results and the personal and political attitudes of the involved scientists.
Wilhelm Müller Johann Ludwig Wilhelm Müller (7 October 1794 – 30 September 1827) was a German lyric poet, best known as the author of ''Die schöne Müllerin'' (1821) and ''Winterreise'' (1823). These would later be the source of inspiration for two song cy ...
replaced Sommerfeld at the Ludwig Maximilian University of Munich. Müller was not a theoretical physicist, had not published in a physics journal, and was not a member of the
German Physical Society The German Physical Society (German: , DPG) is the oldest organisation of physicists. As of 2022, the DPG's worldwide membership is cited as 52,220, making it one of the largest national physics societies in the world. The DPG's membership peaked ...
. His appointment was considered a travesty and detrimental to educating theoretical physicists. The three investigators who led the SS investigation of Heisenberg had training in physics. Indeed, Heisenberg had participated in the doctoral examination of one of them at the
Universität 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 ...
. The most influential of the three was Johannes Juilfs. During their investigation, they became supporters of Heisenberg as well as his position against the ideological policies of the ''Deutsche Physik'' movement in theoretical physics and academia.


German nuclear weapons program


Pre-war work on physics

In mid-1936, Heisenberg presented his theory of
cosmic-ray Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Sol ...
showers in two papers. Four more papers appeared in the next two years. In December 1938, the German chemists
Otto Hahn Otto Hahn (; 8 March 1879 – 28 July 1968) was a German chemist who was a pioneer in the field of radiochemistry. He is referred to as the father of nuclear chemistry and discoverer of nuclear fission, the science behind nuclear reactors and ...
and
Fritz Strassmann Friedrich Wilhelm Strassmann (; 22 February 1902 – 22 April 1980) was a German chemist who, with Otto Hahn in December 1938, identified the element barium as a product of the bombardment of uranium with neutrons. Their observation was the key ...
sent a manuscript to '' The Natural Sciences'' reporting they had detected the element
barium Barium is a chemical element; it has symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. Th ...
after bombarding
uranium Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...
with neutrons, leading Hahn to conclude that a ''bursting'' of the uranium nucleus had occurred; simultaneously, Hahn communicated these results to his friend
Lise Meitner Elise Lise Meitner ( ; ; 7 November 1878 – 27 October 1968) was an Austrian-Swedish nuclear physicist who was instrumental in the discovery of nuclear fission. After completing her doctoral research in 1906, Meitner became the second woman ...
, who had in July of that year fled, first to the Netherlands, then to Sweden. Meitner, and her nephew
Otto Robert Frisch Otto Robert Frisch (1 October 1904 – 22 September 1979) was an Austrian-born British physicist who worked on nuclear physics. With Otto Stern and Immanuel Estermann, he first measured the magnetic moment of the proton. With his aunt, Lise M ...
, correctly interpreted Hahn's and Strassmann's results as being
nuclear fission Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactiv ...
. Frisch confirmed this experimentally on 13 January 1939. In June and July 1939, Heisenberg traveled to the United States visiting
Samuel Abraham Goudsmit Samuel Abraham Goudsmit (July 11, 1902 – December 4, 1978) was a Dutch-American physicist famous for jointly proposing the concept of electron spin with George Eugene Uhlenbeck in 1925. Life and career Goudsmit was born in The Hague, Ne ...
at the
University of Michigan The University of Michigan (U-M, U of M, or Michigan) is a public university, public research university in Ann Arbor, Michigan, United States. Founded in 1817, it is the oldest institution of higher education in the state. The University of Mi ...
in
Ann Arbor Ann Arbor is a city in Washtenaw County, Michigan, United States, and its county seat. The 2020 United States census, 2020 census recorded its population to be 123,851, making it the List of municipalities in Michigan, fifth-most populous cit ...
. However, Heisenberg refused an invitation to emigrate to the United States. He did not see Goudsmit again until six years later, when Goudsmit was the chief scientific advisor to the American
Operation Alsos The Alsos Mission was an organized effort by a team of British and United States military, scientific, and intelligence personnel to discover enemy scientific developments during World War II. Its chief focus was to investigate the progress that ...
at the close of World War II.


Membership in the Uranverein

The
German nuclear weapons program Nazi Germany undertook several research programs relating to nuclear technology, including nuclear weapons and nuclear reactors, before and during World War II. These were variously called () or (). The first effort started in April 1939, ju ...
, known as ''Uranverein'', was formed on 1 September 1939, the day
World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
began in Europe. The ''Heereswaffenamt'' (HWA, Army Ordnance Office) had squeezed the ''
Reichsforschungsrat The Reichsforschungsrat ("Imperial Research Council") was created in Germany in 1936 under the Education Ministry for the purpose of centralized planning of all basic and applied research, with the exception of aeronautical research. It was reorgani ...
'' (RFR, Reich Research Council) out of the ''
Reichserziehungsministerium The Reich Ministry of Science, Education and Culture (, also unofficially known as the "Reich Education Ministry" (), or "REM") existed from 1934 until 1945 under the leadership of Bernhard Rust and was responsible for unifying the education syst ...
'' (REM, Reich Ministry of Education) and started the formal German nuclear energy project under military auspices. The project had its first meeting on 16 September 1939. The meeting was organized by
Kurt Diebner Kurt Diebner (13 May 1905 – 13 July 1964) was a German nuclear physicist who is well known for directing and administering parts of the German nuclear weapons program, a secretive program aiming to build nuclear weapons for Nazi Germany during ...
, advisor to the HWA, and held in Berlin. The invitees included Walther Bothe,
Siegfried Flügge Siegfried Flügge (16 March 1912, in Dresden – 15 December 1997, in Hinterzarten) was a German theoretical physicist who made contributions to nuclear physics and the theoretical basis for nuclear weapons. He worked on the German nuclear ene ...
, Hans Geiger,
Otto Hahn Otto Hahn (; 8 March 1879 – 28 July 1968) was a German chemist who was a pioneer in the field of radiochemistry. He is referred to as the father of nuclear chemistry and discoverer of nuclear fission, the science behind nuclear reactors and ...
, Paul Harteck, Gerhard Hoffmann (physicist), Gerhard Hoffmann, Josef Mattauch and Georg Stetter. A second meeting was held soon thereafter and included Heisenberg, Klaus Clusius, Robert Döpel and
Carl Friedrich von Weizsäcker Carl Friedrich Freiherr von Weizsäcker (; 28 June 1912 – 28 April 2007) was a German physicist and philosopher. He was the longest-living member of the team which performed nuclear research in Nazi Germany during the Second World War, un ...
. The ''Kaiser-Wilhelm Institut für Physik'' (KWIP, Kaiser Wilhelm Institute for Physics) in Dahlem (Berlin), Berlin-Dahlem, was placed under HWA authority, with Diebner as the administrative director, and the military control of the nuclear research commenced. During the period when Diebner administered the KWIP under the HWA program, considerable personal and professional animosity developed between Diebner and Heisenberg's inner circle, which included Karl Wirtz and
Carl Friedrich von Weizsäcker Carl Friedrich Freiherr von Weizsäcker (; 28 June 1912 – 28 April 2007) was a German physicist and philosopher. He was the longest-living member of the team which performed nuclear research in Nazi Germany during the Second World War, un ...
. At a scientific conference on 26–28 February 1942 at the Kaiser Wilhelm Institute for Physics, called by the Army Weapons Office, Heisenberg presented a lecture to Reich officials on energy acquisition from nuclear fission. The lecture, entitled "Die theoretischen Grundlagen für die Energiegewinnung aus der Uranspaltung" ("The theoretical basis for energy generation from uranium fission") was, as Heisenberg wrote after the Second World War in a letter to Samuel Goudsmit, "adapted to the intelligence level of a Reich Minister", as is often done when presenting complex and cutting-edge scientific concepts to laymen. Heisenberg lectured on the enormous energy potential of nuclear fission, stating that 250 million electron volts could be released through the fission of an atomic nucleus. Heisenberg stressed that pure U-235 had to be obtained to achieve a chain reaction. He explored various ways of obtaining isotope in its pure form, including uranium enrichment and an alternative layered method of normal uranium and a moderator in a machine. This machine, he noted, could be used in practical ways to fuel vehicles, ships and submarines. Heisenberg stressed the importance of the Army Weapons Office's financial and material support for this scientific endeavour. A second scientific conference followed. Lectures were heard on problems of modern physics with decisive importance for the national defense and economy. The conference was attended by Bernhard Rust, the Reich Minister of Science, Education and National Culture. At the conference, Reich Minister Rust decided to take the nuclear project away from the Kaiser Wilhelm Society, and give it to the Reich Research Council. In April 1942 the army returned the Physics Institute to the Kaiser Wilhelm Society, naming Heisenberg as Director at the Institute.
Peter Debye Peter Joseph William Debye ( ; born Petrus Josephus Wilhelmus Debije, ; March 24, 1884 – November 2, 1966) was a Dutch-American physicist and physical chemist, and Nobel laureate in Chemistry. Biography Early life Born in Maastricht, Neth ...
was still director of the institute, but had gone on leave to the United States after he had refused to become a German citizen when the HWA took administrative control of the KWIP. Heisenberg still also had his department of physics at the University of Leipzig where work had been done for the ''Uranverein'' by Robert Döpel and his wife Klara Döpel. On 4 June 1942, Heisenberg was summoned to report to Albert Speer, Germany's Minister of Armaments, on the prospects for converting the Uranverein's research toward developing nuclear weapons. During the meeting, Heisenberg told Speer that a bomb could not be built before 1945, because it would require significant monetary resources and number of personnel. After the Uranverein project was placed under the leadership of the Reich Research Council, it focused on nuclear power production and thus maintained its ''kriegswichtig'' (importance for the war) status; funding therefore continued from the military. The nuclear power project was broken down into the following main areas:
uranium Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...
and heavy water production, uranium isotope separation and the ''Uranmaschine'' (uranium machine, i.e.,
nuclear reactor A nuclear reactor is a device used to initiate and control a Nuclear fission, fission nuclear chain reaction. They are used for Nuclear power, commercial electricity, nuclear marine propulsion, marine propulsion, Weapons-grade plutonium, weapons ...
). The project was then essentially split up between a number of institutes, where the directors dominated the research and set their own research agendas. The point in 1942, when the army relinquished its control of the German nuclear weapons program, was the zenith of the project relative to the number of personnel. About 70 scientists worked for the program, with about 40 devoting more than half their time to nuclear fission research. After 1942, the number of scientists working on applied nuclear fission diminished dramatically. Many of the scientists not working with the main institutes stopped working on nuclear fission and devoted their efforts to more pressing war-related work. In September 1942, Heisenberg submitted his first paper of a three-part series on the scattering matrix, or S-matrix, in elementary particle physics. The first two papers were published in 1943 and the third in 1944. The S-matrix described only the states of incident particles in a collision process, the states of those emerging from the collision, and stable bound states; there would be no reference to the intervening states. This was the same precedent as he followed in 1925 in what turned out to be the foundation of the matrix formulation of quantum mechanics through only the use of observables. In February 1943, Heisenberg was appointed to the Chair for Theoretical Physics at the ''Friedrich-Wilhelms-Universität'' (today, the Humboldt University of Berlin, Humboldt-Universität zu Berlin). In April, his election to the ''Preußische Akademie der Wissenschaften'' (Prussian Academy of Sciences) was approved. That same month, he moved his family to their retreat in :de:Urfeld am Walchensee, Urfeld as Allied bombing increased in Berlin. In the summer, he dispatched the first of his staff at the ''Kaiser-Wilhelm Institut für Physik'' to Hechingen and its neighboring town of Haigerloch, on the edge of the Black Forest, for the same reasons. From 18–26 October, he travelled to German-occupied Netherlands. In December 1943, Heisenberg visited History of Poland (1939–1945), German-occupied Poland. From 24 January to 4 February 1944, Heisenberg travelled to occupied Copenhagen, after the German army confiscated Bohr's Institute of Theoretical Physics. He made a short return trip in April. In December, Heisenberg lectured in Switzerland during the World Wars#World War II, neutral Switzerland. The United States Office of Strategic Services sent agent Moe Berg to attend the lecture carrying a pistol, with orders to shoot Heisenberg if his lecture indicated that Germany was close to completing an atomic bomb. In January 1945, Heisenberg, with most of the rest of his staff, moved from the ''Kaiser-Wilhelm Institut für Physik'' to the facilities in the Black Forest.


Post-Second World War


1945: Alsos Mission

The Alsos Mission was an Allied effort to determine whether the Germans had an atomic bomb program and to exploit German atomic-related facilities, research, material resources, and scientific personnel for the benefit of the US. Personnel on this operation generally swept into areas that had just come under control of the Allied military forces, but sometimes they operated in areas still under control by German forces.Boris Pash, Pash, Boris T. (1969) ''The Alsos Mission''. Award. pp. 219–241. Berlin had been a location of many German scientific research facilities. To limit casualties and loss of equipment, many of these facilities were dispersed to other locations in the latter years of the war. The ''Kaiser-Wilhelm-Institut für Physik'' (KWIP, Kaiser Wilhelm Institute for Physics) had been bombed so it had mostly been moved in 1943 and 1944 to Hechingen and its neighbouring town of Haigerloch, on the edge of the Black Forest, which eventually became included in the French occupation zone. This allowed the American task force of the Alsos Mission to take into custody a large number of German scientists associated with nuclear research. On 30 March, the Alsos Mission reached Heidelberg, where important scientists were captured including Walther Bothe, Richard Kuhn,
Philipp Lenard Philipp Eduard Anton von Lenard (; ; 7 June 1862 – 20 May 1947) was a Hungarian-German physicist who received the Nobel Prize in Physics in 1905 "for his work on cathode rays" and the discovery of many of their properties. One of his most im ...
, and Wolfgang Gentner. Their interrogation revealed that Otto Hahn was at his laboratory in Tailfingen, while Heisenberg and Max von Laue were at Heisenberg's laboratory in Hechingen, and that the experimental natural uranium reactor that Heisenberg's team had built in Berlin had been moved to Haigerloch. Thereafter, the main focus of the Alsos Mission was on these nuclear facilities in the Württemberg area. Heisenberg was smuggled out from Urfeld, on 3 May 1945, in an alpine operation in territory still under control by elite German forces. He was taken to Heidelberg, where, on 5 May, he met Goudsmit for the first time since the Ann Arbor visit in 1939. Germany surrendered just two days later. Heisenberg would not see his family again for eight months, as he was moved across France and Belgium and flown to England on 3 July 1945.


1945: Reaction to Hiroshima

Nine of the prominent German scientists who published reports in ''Kernphysikalische Forschungsberichte, Nuclear Physics Research Reports'' as members of the ''Uranverein'' were captured by Operation Alsos and incarcerated in England under Operation Epsilon. Ten German scientists, including Heisenberg, were held at Farm Hall in England. The facility had been a safe house of the British foreign intelligence Secret Intelligence Service, MI6. During their detention, their conversations were recorded. Conversations thought to be of intelligence value were transcribed and translated into English. The transcripts were released in 1992. On 6 August 1945, the scientists at Farm Hall learned from media reports that the US had dropped an atomic bomb in Hiroshima, Japan. At first, there was disbelief that a bomb had been built and dropped. In the weeks that followed, the German scientists discussed how the United States might have built the bomb. The Farm Hall transcripts reveal that Heisenberg, along with other physicists interned at Farm Hall including Otto Hahn and
Carl Friedrich von Weizsäcker Carl Friedrich Freiherr von Weizsäcker (; 28 June 1912 – 28 April 2007) was a German physicist and philosopher. He was the longest-living member of the team which performed nuclear research in Nazi Germany during the Second World War, un ...
, were glad the Allies had won World War II. Heisenberg told other scientists that he had never contemplated a bomb, only an atomic pile to produce energy. The morality of creating a bomb for the Nazi Party, Nazis was also discussed. Only a few of the scientists expressed genuine horror at the prospect of nuclear weapons, and Heisenberg himself was cautious in discussing the matter. On the failure of the German nuclear weapons program to build an atomic bomb, Heisenberg remarked, "We wouldn't have had the moral courage to recommend to the government in the spring of 1942 that they should employ 120,000 men just for building the thing up." When in 1992 the transcripts were declassified, German physicist :de:Manfred Popp, Manfred Popp analyzed the transcripts, as well as the documentation of Uranverein. When the German scientists heard about the Hiroshima bomb, Heisenberg admitted that he had never calculated the critical mass of an atomic bomb before. When he subsequently attempted to calculate the mass, he made serious calculation errors.
Edward Teller Edward Teller (; January 15, 1908 – September 9, 2003) was a Hungarian and American Theoretical physics, theoretical physicist and chemical engineer who is known colloquially as "the father of the hydrogen bomb" and one of the creators of ...
and Hans Bethe saw the transcript, and drew the conclusion that Heisenberg had done it for the first time as he made similar errors as they had. Only a week later Heisenberg gave a lecture about the physics of the bomb. He correctly recognized many essential aspects, including the efficiency of the bomb, although he still underestimated it. For Popp, this is proof that Heisenberg did not spend time on a nuclear weapon during the war; on the contrary, he avoided even thinking about it.


Post-war research career


Executive positions at German research institutions

On 3 January 1946, the ten Operation Epsilon detainees were transported to Alswede in Germany. Heisenberg settled in Göttingen, which was in the British zone of Allied-occupied Germany. Heisenberg immediately began to promote scientific research in Germany. Following the Kaiser Wilhelm Society's dissolution by the Allied Control Council and the establishment of the Max Planck Society in the British zone, Heisenberg became the director of the
Max Planck Institute for Physics The Max Planck Institute for Physics (MPP) is a research institute located in Garching, near Munich, Germany. It specializes in high energy physics and astroparticle physics. The MPP is part of the Max Planck Society and is also known as the We ...
. Max von Laue was appointed vice director, while Karl Wirtz,
Carl Friedrich von Weizsäcker Carl Friedrich Freiherr von Weizsäcker (; 28 June 1912 – 28 April 2007) was a German physicist and philosopher. He was the longest-living member of the team which performed nuclear research in Nazi Germany during the Second World War, un ...
and Ludwig Biermann joined to help Heisenberg establish the institute. Heinz Billing joined in 1950 to promote the development of electronic computing. The core research focus of the institute was cosmic radiation. The institute held a colloquium every Saturday morning. Heisenberg together with was instrumental in the establishment of the Forschungsrat (research council). Heisenberg envisaged this council to promote the dialogue between the newly founded Federal Republic of Germany and the scientific community, based in Germany. Heisenberg was appointed president of the ''Forschungsrat''. In 1951, the organization was fused with the Notgemeinschaft der Deutschen Wissenschaft (Emergency Association of German Science) and that same year renamed the Deutsche Forschungsgemeinschaft (German Research Foundation). Following the merger, Heisenberg was appointed to the presidium. In 1958, the Max Planck Institute for Physics, Max-Planck-Institut für Physik was moved to Munich, expanded, and renamed Max Planck Institute for Astrophysics, Max-Planck-Institut für Physik und Astrophysik (MPIFA). In the interim, Heisenberg and the astrophysicist Ludwig Biermann were co-directors of MPIFA. Heisenberg also became an ''ordentlicher Professor'' (ordinarius professor) at the
Ludwig-Maximilians-Universität München 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 ...
. Heisenberg was the sole director of MPIFA from 1960 to 1970. Heisenberg resigned his directorship of the MPIFA on 31 December 1970.


Promotion of international scientific cooperation

In 1951, Heisenberg agreed to become the scientific representative of the Federal Republic of Germany at the UNESCO conference, with the aim of establishing a European laboratory for nuclear physics. Heisenberg's aim was to build a large particle accelerator, drawing on the resources and technical skills of scientists across the Western Bloc. On 1 July 1953 Heisenberg signed the convention that established CERN on behalf of the Federal Republic of Germany. Although he was asked to become CERN's founding scientific director, he declined. Instead, he was appointed chair of CERN's science policy committee and went on to determine the scientific program at CERN. In December 1953, Heisenberg became the president of the
Alexander von Humboldt Foundation The Alexander von Humboldt Foundation () is a foundation that promotes international academic cooperation between scientists and scholars from Germany and abroad. Established by the government of the Federal Republic of Germany, it is funded by t ...
. During his tenure as president 550 Humboldt scholars from 78 nations received scientific research grants. Heisenberg resigned as president shortly before his death.


Research interests

In 1946, the German scientist Heinz Pose, head of Laboratory V in Obninsk, wrote a letter to Heisenberg inviting him to work in the USSR. The letter lauded the working conditions in the USSR and the available resources, as well as the favorable attitude of the Soviets towards German scientists. A courier hand delivered the recruitment letter, dated 18 July 1946, to Heisenberg; Heisenberg politely declined. In 1947, Heisenberg presented lectures in Cambridge, Edinburgh and Bristol. Heisenberg contributed to the understanding of the phenomenon of superconductivity with a paper in 1947 and two papers in 1948, one of them with Max von Laue. In the period shortly after World War II, Heisenberg briefly returned to the subject of his doctoral thesis, turbulence. Three papers were published in 1948 and one in 1950. In the post-war period Heisenberg continued his interests in cosmic-ray showers with considerations on multiple production of mesons. He published three papers in 1949, two in 1952, and one in 1955. In late 1955 to early 1956, Heisenberg gave the Gifford Lectures at University of St Andrews, St Andrews University, in Scotland, on the intellectual history of physics. The lectures were later published as ''Physics and Philosophy: The Revolution in Modern Science''. During 1956 and 1957, Heisenberg was the chairman of the ''Arbeitskreis Kernphysik'' (Nuclear Physics Working Group) of the ''Fachkommission II "Forschung und Nachwuchs"'' (Commission II "Research and Growth") of the ''Deutsche Atomkommission'' (DAtK, German Atomic Energy Commission). Other members of the Nuclear Physics Working Group in both 1956 and 1957 were: Walther Bothe, Hans Kopfermann (vice-chairman), Fritz Bopp, Wolfgang Gentner, Otto Haxel, Willibald Jentschke, Heinz Maier-Leibnitz, Josef Mattauch, , Wilhelm Walcher and
Carl Friedrich von Weizsäcker Carl Friedrich Freiherr von Weizsäcker (; 28 June 1912 – 28 April 2007) was a German physicist and philosopher. He was the longest-living member of the team which performed nuclear research in Nazi Germany during the Second World War, un ...
. Wolfgang Paul was also a member of the group during 1957. In 1957, Heisenberg was a signatory of the Göttinger Manifest, taking a public stand against the Federal Republic of Germany arming itself with nuclear weapons. Heisenberg, like
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 ...
, thought politicians would ignore this statement by nuclear scientists. But Heisenberg believed that the Göttinger Manifest would "influence public opinion" which politicians would have to take into account. He wrote to Walther Gerlach: "We will probably have to keep coming back to this question in public for a long time because of the danger that public opinion will slacken." In 1961 Heisenberg signed the Memorandum of Tübingen alongside a group of scientists who had been brought together by
Carl Friedrich von Weizsäcker Carl Friedrich Freiherr von Weizsäcker (; 28 June 1912 – 28 April 2007) was a German physicist and philosopher. He was the longest-living member of the team which performed nuclear research in Nazi Germany during the Second World War, un ...
and Ludwig Raiser. A public discussion between scientists and politicians ensued. As prominent politicians, authors and socialites joined the debate on nuclear weapons, the signatories of the memorandum took a stand against "the full-time intellectual nonconformists". From 1957 onwards, Heisenberg was interested in plasma physics and the process of nuclear fusion. He also collaborated with the International Institute of Atomic Physics in Geneva. He was a member of the Institute's scientific policy committee, and for several years was the Committee's chair. He was one of the eight signatories of the Memorandum of Tübingen which called for the recognition of the Oder–Neisse line, Oder–Neiße line as the official border between Germany and Poland and spoke against a possible nuclear armament of West Germany. In 1973, Heisenberg gave a lecture at Harvard University on the historical development of the concepts of Quantum mechanics, quantum theory. On 24 March 1973 Heisenberg gave a speech before the Catholic Academy of Bavaria, accepting the Romano Guardini Prize. An English translation of his speech was published under the title "Scientific and Religious Truth", a quotation from which appears in a later section of this article.


Philosophy and worldview

Heisenberg admired Eastern philosophy and saw parallels between it and quantum mechanics, describing himself as in "complete agreement" with the book ''The Tao of Physics''. Heisenberg even went as far to state that after conversations with Rabindranath Tagore about Indian philosophy "some of the ideas that seemed so crazy suddenly made much more sense". Regarding the Scientific law, laws of nature he remarked that "the concept of 'the law of nature' cannot be completely objective, the word 'law' being a purely human principle". Regarding the philosophy of Ludwig Wittgenstein, Heisenberg disliked ''Tractatus Logico-Philosophicus'' but he liked "very much the later ideas of Wittgenstein and his philosophy about language." Heisenberg, a devout Christian, wrote: "We can console ourselves that the good Lord God would know the position of the [subatomic] particles, thus He would let the causality principle continue to have validity", in his last letter to Albert Einstein. Einstein continued to maintain that quantum physics must be incomplete because it implies that the universe is indeterminate at a fundamental level. In lectures given in the 1950s and later published as ''Physics and Philosophy'', Heisenberg contended that scientific advances were leading to cultural conflicts. He stated that modern physics is "part of a general historical process that tends toward a unification and a widening of our present world". When Heisenberg accepted the in 1974, he gave a speech, which he later published under the title ''Scientific and Religious Truth''. He mused: Heisenberg referred to nature as "God's second book" (the first being the Bible) and believed that "Physics is reflection on the divine ideas of Creation; therefore physics is divine service". This was because "God created the world in accordance with his ideas of creation" and humans can understand the world because "Man was created as the spiritual image of God".


Political stance

Heisenberg never participated in explicit Propaganda in Nazi Germany, National Socialist propaganda. However, he fully supported Nazi Germany's project of New Order (Nazism), European "renewal", which corresponded with his German-Imperialism, imperialist convictions. The Dutch physicist Hendrik Casimir recalled hearing from Heisenberg in 1943 that German world domination was a historical necessity due to the weakness of Western Liberal democracy, liberal democracy and the alternative of History of communism in the Soviet Union, Soviet Communism. According to the British-German physicist
Rudolf Peierls Sir Rudolf Ernst Peierls, (; ; 5 June 1907 – 19 September 1995) was a German-born British physicist who played a major role in Tube Alloys, Britain's nuclear weapon programme, as well as the subsequent Manhattan Project, the combined Allied ...
, while visiting England in 1947 Heisenberg told a colleague who had been forced to emigrate from Germany that after another fifty years in power the Nazis "would have become quite decent". The Austrian-Swedish physicist
Lise Meitner Elise Lise Meitner ( ; ; 7 November 1878 – 27 October 1968) was an Austrian-Swedish nuclear physicist who was instrumental in the discovery of nuclear fission. After completing her doctoral research in 1906, Meitner became the second woman ...
quoted Heisenberg's 1948 reply to being confronted with German atrocities: "Unfortunately, every spiritual upheaval has always been accompanied by great cruelty". Heisenberg, who did not leave Germany during the Nazi rule, was also unwilling to emigrate after the war. Responding to an offer of permanent Financial endowment, endowed employment at Yale University in 1951 conveyed by Gregory Breit, he stated he would have considered it only if World War III had broken out and the Soviet Union had occupied Göttingen.


Autobiography and death

In his late sixties, Heisenberg penned his autobiography for the mass market. In 1969 the book was published in Germany, in early 1971 it was published in English and in the years thereafter in a string of other languages. Heisenberg initiated the project in 1966, when his public lectures increasingly turned to the subjects of philosophy and religion. Heisenberg had sent the manuscript for a textbook on the unified field theory to Hirzel Verlag and John Wiley & Sons for publication. This manuscript, he wrote to one of his publishers, was the preparatory work for his autobiography. He structured his autobiography in themes, covering: 1) The goal of exact science, 2) The problematic of language in atomic physics, 3) Abstraction in mathematics and science, 4) The divisibility of matter or Kant's antinomy, 5) The basic symmetry and its substantiation, and 6) Science and religion. Heisenberg wrote his memoirs as a chain of conversations, covering the course of his life. The book became a popular success, but was regarded as troublesome by historians of science. In the preface Heisenberg wrote that he had abridged historical events, to make them more concise. At the time of publication, it was reviewed by Paul Forman (historian), Paul Forman in the journal ''Science'' with the comment "Now here is a memoir in the form of rationally reconstructed dialogue. And the dialogue as Galileo well knew, is itself a most insidious literary device: lively, entertaining, and especially suited for insinuating opinions while yet evading responsibility for them." Few scientific memoirs had been published, but Konrad Lorenz and Adolf Portmann had penned popular books that conveyed scholarship to a wide audience. Heisenberg worked on his autobiography and published it with the Piper Verlag in Munich. Heisenberg initially proposed the title ''Gespräche im Umkreis der Atomphysik'' (''Conversations on Atomic Physics''). The autobiography was published eventually under the title ''Der Teil und das Ganze'' (''The Part and the Whole''). The 1971 English translation was published under the title ''Physics and Beyond: Encounters and Conversations''. Heisenberg died of kidney cancer at his home, on 1 February 1976. The next evening, his colleagues and friends walked in remembrance from the Institute of Physics to his home, lit a candle and placed it in front of his door. Heisenberg is buried in Munich Waldfriedhof. In 1980 his widow, Elisabeth Heisenberg, published ''Das politische Leben eines Unpolitischen'' (''The Political Life of an Apolitical Person''), in which she characterized Heisenberg as "first and foremost, a spontaneous person, thereafter a brilliant scientist, next a highly talented artist, and only in the fourth place, from a sense of duty, homo politicus".


Honors and awards

Heisenberg was awarded a number of honors: * Honorary degree, Honorary doctorates from the Université libre de Bruxelles, University of Brussels, the Karlsruhe Institute of Technology, Technological University of Karlsruhe, and Eötvös Loránd University. * Bavarian Order of Merit * Romano Guardini Prize * Bundesverdienstkreuz, Grand Cross for Federal Service with Star * Pour le Mérite (Civil Class) * Elected an International Member of the American Philosophical Society in 1937, a List of Fellows of the Royal Society elected in 1955, Foreign Member of the Royal Society (ForMemRS) in 1955, and an International Honorary Member of the American Academy of Arts and Sciences in 1958. * Member of the Academies of Sciences of Göttingen, Bavaria, Saxony, Prussia, Sweden, Romania, Norway, Spain, The Netherlands (1939), Rome (Pontifical), the ''German Academy of Sciences Leopoldina, Deutsche Akademie der Naturforscher Leopoldina'' (Halle), the Accademia dei Lincei (Rome), and the American National Academy of Sciences, Academy of Sciences. * 1932 –
Nobel Prize in Physics The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...
"for the creation of quantum mechanics, the application of which has, inter alia, led to the discovery of the allotropic forms of hydrogen". * 1933 – ''Max Planck Medal, Max-Planck-Medaille'' of the ''Deutsche Physikalische Gesellschaft''


Research reports on nuclear physics

The following reports were published in ''Kernphysikalische Forschungsberichte'' (''Research Reports in Nuclear Physics''), an internal publication of the German ''German nuclear energy project, Uranverein''. The reports were classified Top Secret, they had very limited distribution, and the authors were not allowed to keep copies. The reports were confiscated under the Allied
Operation Alsos The Alsos Mission was an organized effort by a team of British and United States military, scientific, and intelligence personnel to discover enemy scientific developments during World War II. Its chief focus was to investigate the progress that ...
and sent to the United States Atomic Energy Commission for evaluation. In 1971, the reports were declassified and returned to Germany. The reports are available at the Forschungszentrum Karlsruhe, Karlsruhe Nuclear Research Center and the American Institute of Physics. * Werner Heisenberg ''Die Möglichkeit der technischer Energiegewinnung aus der Uranspaltung'' G-39 (6 December 1939) * Werner Heisenberg ''Bericht über die Möglichkeit technischer Energiegewinnung aus der Uranspaltung (II)'' G-40 (29 February 1940) * Robert Döpel, K. Döpel, and Werner Heisenberg ''Bestimmung der Diffusionslänge thermischer Neutronen in schwerem Wasser'' G-23 (7 August 1940) *Robert Döpel, Klara Döpel, K. Döpel, and Werner Heisenberg ''Bestimmung der Diffusionslänge thermischer Neutronen in Präparat 38'' G-22 (5 December 1940) * Robert Döpel, K. Döpel, and Werner Heisenberg ''Versuche mit Schichtenanordnungen von D2O und 38'' G-75 (28 October 1941) * Werner Heisenberg ''Über die Möglichkeit der Energieerzeugung mit Hilfe des Isotops 238'' G-92 (1941) * Werner Heisenberg ''Bericht über Versuche mit Schichtenanordnungen von Präparat 38 und Paraffin am Kaiser Wilhelm Institut für Physik in Berlin-Dahlem'' G-93 (May 1941) *Fritz Bopp, Erich Fischer, Werner Heisenberg, Carl Friedrich von Weizsäcker, Carl-Friedrich von Weizsäcker, and Karl Wirtz ''Untersuchungen mit neuen Schichtenanordnungen aus U-metall und Paraffin'' G-127 (March 1942) * Robert Döpel ''Bericht über Unfälle beim Umgang mit Uranmetall'' G-135 (9 July 1942) * Werner Heisenberg ''Bemerkungen zu dem geplanten halbtechnischen Versuch mit 1,5 to D2O und 3 to 38-Metall'' G-161 (31 July 1942) * Werner Heisenberg, Fritz Bopp, Erich Fischer, Carl Friedrich von Weizsäcker, Carl-Friedrich von Weizsäcker, and Karl Wirtz ''Messungen an Schichtenanordnungen aus 38-Metall und Paraffin'' G-162 (30 October 1942) * Robert Döpel, K. Döpel, and Werner Heisenberg ''Der experimentelle Nachweis der effektiven Neutronenvermehrung in einem Kugel-Schichten-System aus D2O und Uran-Metall'' G-136 (July 1942) * Werner Heisenberg ''Die Energiegewinnung aus der Atomkernspaltung'' G-217 (6 May 1943) *Fritz Bopp, Walther Bothe, Erich Fischer, Erwin Fünfer, Werner Heisenberg, Oskar Ritter, O. Ritter, and Karl Wirtz ''Bericht über einen Versuch mit 1.5 to D2O und U und 40 cm Kohlerückstreumantel (B7)'' G-300 (3 January 1945) * Robert Döpel, K. Döpel, and Werner Heisenberg ''Die Neutronenvermehrung in einem D2O-38-Metallschichtensystem'' G-373 (March 1942)


Other research publications

* * * * * * * * * The paper was received on 29 July 1925. [English translation in: ] This is the first paper in the famous trilogy which launched the
matrix mechanics Matrix mechanics is a formulation of quantum mechanics created by Werner Heisenberg, Max Born, and Pascual Jordan in 1925. It was the first conceptually autonomous and logically consistent formulation of quantum mechanics. Its account of quantum ...
formulation of quantum mechanics. * The paper was received on 27 September 1925. [English translation in: ] This is the second paper in the famous trilogy which launched the
matrix mechanics Matrix mechanics is a formulation of quantum mechanics created by Werner Heisenberg, Max Born, and Pascual Jordan in 1925. It was the first conceptually autonomous and logically consistent formulation of quantum mechanics. Its account of quantum ...
formulation of quantum mechanics. * The paper was received on 16 November 1925. [English translation in: ] This is the third paper in the famous trilogy which launched the
matrix mechanics Matrix mechanics is a formulation of quantum mechanics created by Werner Heisenberg, Max Born, and Pascual Jordan in 1925. It was the first conceptually autonomous and logically consistent formulation of quantum mechanics. Its account of quantum ...
formulation of quantum mechanics. * * * * * * * * The author was cited as being at Leipzig. The paper was received on 21 June 1934. * * The authors were cited as being at Leipzig. The paper was received on 22 December 1935. A translation of this paper has been done by W. Korolevski and H. Kleinert: arxiv:physics/0605038v1, arXiv:physics/0605038v1. * * * * * * * * * * * * * * * * * * * * * * The substance of this article was presented by Heisenberg in a lecture at Harvard University.


Published books

* * * * * * * * * * * * * * * * * * (iarchive:PhysicsPhilosophy, full text of 1958 version)


In popular culture

Heisenberg's surname is used as the primary Secret identity, alias for Walter White (Breaking Bad), Walter White (played by Bryan Cranston), the lead character in AMC (TV channel), AMC's crime drama series ''Breaking Bad'', throughout White's transformation from a high-school chemistry teacher into a methamphetamine, meth cook and a drug kingpin. In the spin-off prequel series ''Better Call Saul'', a German character named Werner directs the construction of the meth lab belonging to antagonist Gus Fring that Walt cooks in for much of ''Breaking Bad''. Heisenberg was the target of an assassination by spy Moe Berg in the film ''The Catcher Was a Spy (film), The Catcher Was a Spy'', based on real events. Heisenberg is also credited with building the atomic bomb used by the Axis in the Amazon Prime Video, Amazon The Man in the High Castle (TV series), TV series adaptation of the novel ''The Man in the High Castle'' by Philip K. Dick. Atomic bombs in this universe are referred to as Heisenberg Devices. The 2015 TV film ''Kampen om Tongtvannet'' (''The Heavy Water War: Stopping Hitler's Atomic Bomb'') directed by Per-Olav Sørensen, extensively features Werner Heisenberg and his career, including his nuclear research under the Nazis. Daniel Craig portrayed Heisenberg in the 2002 film ''Copenhagen (2002 film), Copenhagen,'' an adaptation of Michael Frayn's Copenhagen (play), play. Matthias Schweighöfer portrayed Heisenberg in the 2023 biopic ''Oppenheimer (film), Oppenheimer''. Heisenberg is the namesake of ''Resident Evil Village'' secondary antagonist Karl Heisenberg. Heisenberg's research on ferromagnetism served as inspiration for the character's magnetic abilities. In the television series ''Star Trek: The Next Generation'', the "Heisenberg compensator" is an essential component of Transporter (Star Trek), transporter technology to ensure the integrity of transported matter. The compensator counteracts effects of the applied characteristics identified in Heisenberg's uncertainty principle. To accurately isolate matter prior to its entry into the transporter buffer, all particles must be located, their velocity observed, and tracked; the compensators allow this to happen.


See also

* List of things named after Werner Heisenberg * List of German inventors and discoverers * ''The Physical Principles of the Quantum Theory'' * Haigerloch research reactor


References

Footnotes Citations


Bibliography

* *
See also * * * * * *David Clary, Clary, David C. (2022)
''Schrödinger in Oxford''
World Scientific Publishing. . * * * * * * * * * The author was cited as being at Leipzig. The paper was received on 21 June 1934. * * * The authors were cited as being at Leipzig. The paper was received on 22 December 1935. A translation of this paper has been done by W. Korolevski and H. Kleinert: arxiv:physics/0605038v1, arXiv:physics/0605038v1. * [This book is a collection of 121 primary German documents relating to physics under National Socialism. The documents have been translated and annotated, and there is a lengthy introduction to put them into perspective.] * * * * * * *


External links


Annotated Bibliography for Werner Heisenberg
from the Alsos Digital Library for Nuclear Issues * MacTutor History of Mathematics archive, MacTutor Biography
Werner Karl Heisenberg

Heisenberg/Uncertainty
biographical exhibit by American Institute of Physics.
Key Participants: Werner Heisenberg
– ''Linus Pauling and the Nature of the Chemical Bond: A Documentary History''



* * * {{DEFAULTSORT:Heisenberg, Werner Werner Heisenberg, 1901 births 1976 deaths Scientists from Würzburg Foreign members of the Royal Society German Lutherans German mountain climbers German Nobel laureates Grand Crosses with Star and Sash of the Order of Merit of the Federal Republic of Germany Heisenberg family, Werner Academic staff of the Humboldt University of Berlin Ludwig Maximilian University of Munich alumni Max Planck Society people Members of the Pontifical Academy of Sciences Members of the Prussian Academy of Sciences Members of the Royal Netherlands Academy of Arts and Sciences Foreign associates of the National Academy of Sciences Nobel laureates in Physics 20th-century German physicists Nuclear program of Nazi Germany Scientists from the Kingdom of Bavaria German philosophers of science German quantum physicists German fluid dynamicists Recipients of the Pour le Mérite (civil class) Scouting and Guiding in Germany German theoretical physicists Academic staff of the University of Göttingen Academic staff of Leipzig University Burials at Munich Waldfriedhof Winners of the Max Planck Medal Niels Bohr International Gold Medal recipients Members of the Bavarian Academy of Sciences Operation Epsilon People associated with CERN Members of the German Academy of Sciences at Berlin Recipients of the Matteucci Medal Members of the Göttingen Academy of Sciences and Humanities 20th-century Freikorps personnel Max Planck Institute directors International members of the American Philosophical Society