Werner Heisenberg

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Werner Heisenberg
Werner Karl Heisenberg, ca. 1926-1927
Born	5 December 1901(1901-12-05) Würzburg, Germany
Died	February 1, 1976 (aged 74) Munich, Germany
Nationality	Germany
Fields	Physics
Institutions	University of Göttingen (1924) University of Copenhagen (1926-27) University of Leipzig (1927-41) University of Berlin (1941) University of St. Andrews (1955-56) University of Munich (1958)
Alma mater	University of Munich
Doctoral advisor	Arnold Sommerfeld
Doctoral students	Felix Bloch Edward Teller Rudolph E. Peierls Friedwardt Winterberg
Known for	Uncertainty Principle Quantum Mechanics
Notable awards	Nobel Prize in Physics (1932)

Werner Karl Heisenberg (December 5, 1901 – February 1, 1976) was a celebrated German physicist and Nobel laureate, one of the founders of quantum mechanics and acknowledged to be one of the most important physicists of the twentieth century. Heisenberg was the head of the German nuclear energy project under the Nazi regime, though the nature of this project, and his work in this capacity, has been heavily debated. He is most well-known for discovering one of the central principles of modern physics, the Heisenberg uncertainty principle, and for the development of quantum mechanics, for which he was awarded the Nobel Prize in Physics in 1932.

Contents 1 Family 2 Quantum mechanics 3 Controversy in prewar Germany 4 Work during the War 5 Postwar biography and controversy 6 References 7 External links

[edit] Family

He was the son of Dr. August Heisenberg, professor of the middle and modern Greek language at the University of Munich, Germany and Annie Wecklein. In 1937, he married Elisabeth Schumacher with whom he had seven children; Maria, Jochen, Barbara, Wolfgang, Christine, Verena, and neurobiologist and geneticist Martin Heisenberg.

[edit] Quantum mechanics

As a student, he met Niels Bohr in Göttingen in 1922. A fruitful and life long collaboration^{[citation needed]} developed between the two.

He invented matrix mechanics, the first formalization of quantum mechanics in 1925, which he developed with the help of Max Born and Pascual Jordan. His uncertainty principle, developed in 1927, states that the simultaneous determination of two paired quantities, for example the position and momentum of a particle, has an unavoidable uncertainty. Together with Bohr, he formulated the Copenhagen interpretation of quantum mechanics.

He received the Nobel Prize in physics in 1932 for "the creation of quantum mechanics, the application of which has, inter alia, led to the discovery of the allotropic forms of hydrogen".

In the late 1920s and early '30s, Heisenberg collaborated with Wolfgang Pauli, and along with Paul Dirac, developed an early version of quantum electrodynamics. However, at the time, nobody could get rid of the infinities plaguing the theory, and it was only after World War II that a technique called renormalization was invented to take care of the infinities.

After the discovery of the neutron by James Chadwick in 1932, Heisenberg proposed the proton-neutron model of the atomic nucleus and used it to explain the nuclear spin of isotopes.

[edit] Controversy in prewar Germany

On 1 April 1935 Arnold Sommerfeld, Heisenberg’s teacher and doctoral advisor at the University of Munich, achieved emeritus status. However, Sommerfeld stayed on as his own temporary replacement 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 both the Reichserziehungsministerium (REM, Reich Education Ministry.) and the supporters of deutsche Physik, which was anti-Semitic and had a bias against theoretical physics, especially including quantum mechanics. In 1935, the Munich Faculty drew up a candidate list to replace Sommerfeld as ordinarius professor of theoretical physics and head of the Institute for Theoretical Physics at the University of Munich. There were three names on the list: Werner Heisenberg, who received the Nobel Prize in Physics in 1932, Peter Debye, who would receive the Nobel Prize in Chemistry in 1936, and Richard Becker - all former students of Sommerfeld. 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 commenced, dragging on for over four years. During this time, Heisenberg, came under vicious attack by the supporters of deutsche Physik. One such attack was published in Das Schwarze Korps, the newspaper of the Schutzstaffel, or SS, headed by Heinrich Himmler. In the editorial, Heisenberg was called a “White Jew” who should be made to “disappear.”^[1] These verbal attacks were taken seriously, as there was physical violence against the Jews and they were incarcerated. Heisenberg fought back with an editorial and a letter to Himmler, in an attempt to get a resolution to this matter and regain his honor. At one point, Heisenberg’s mother visited Himmler’s mother to help bring a resolution to the affair. The two women knew each other as a result of Heisenberg’s maternal grandfather and Himmler’s father being rectors and members of a Bavarian hiking club. Eventually, Himmler settled the Heisenberg affair by sending two letters, one to SS-Gruppenführer Reinhard 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 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. The letter to Heisenberg was signed under the closing “Mit freundlichem Gruss und, Heil Hitler!” (With friendly greetings, Heil Hitler!”)^[2] Overall, the Heisenberg affair was settled with a victory for academic standards and professionalism, however, with Wilhelm Müller taking over for Sommerfeld on 1 December 1939, this appointment was a political victory over academic standards. Müller was not a theoretical physicist, had not published in a physics journal, and was not a member of the Deutsche Physikalische Gesellschaft; his appointment as a replacement for Sommerfeld was considered a travesty and detrimental to educating a new generation of theoretical physicists.^{[3] [4] [5] [6] [7]}

[edit] Work during the War

Nuclear fission was discovered in Germany in 1938. Heisenberg remained in Germany during World War II, ostensibly to help rebuild German science after the extensive brain drain that occurred in the 1930s as a result of Nazi policies banning Jews from government jobs, which led to the expulsion of Jewish physics professors from the state universities. Heisenberg by all accounts was loyal to Germany, but not the Nazi regime. The Kaiser Wilhelm Institute for Physics (of which he was the Director) was appropriated by the Nazi Heereswaffenamt (Army Ordnance Board). He belonged to a team led by Walther Bothe to develop one of Germany's many nuclear weapon/nuclear power programs, but the extent of his cooperation in the development of weapons has been a subject of much controversy. Heisenberg's work consisted of various efforts to create sustained fission reactions. A rival atomic bomb project was led by Kurt Diebner for Heereswaffenamt, who, with Paul Harteck worked on uranium enrichment and a uranium-based atomic bomb. Neither team was successful before the end of the war, because of various factors including complications from various invasions toward the end of the war and lack of funding from the government. After the military reversals the Wehrmacht (German Army) suffered at the Russian Front during the winter of 1941-42, uranium research was downgraded in priority by the Reich's director of military research.^[8]

There has been speculation that Heisenberg had moral qualms and tried to slow down the project. Allegations have been put forward that Heisenberg himself may have attempted to paint this picture after the war, however it is supported by substantial facts. Thomas Powers' book Heisenberg's War and Michael Frayn's play Copenhagen adopted this interpretation. This is because during a June 1942 meeting with Albert Speer, the minister for Nazi munitions, Heisenberg did not champion the project in a way which got it much attention or funding (which Samuel Goudsmit of the Alsos project interpreted as being partially because Heisenberg himself was not fully aware of the feasibility of an atomic bomb). At best, he tried to hinder the German project; at worst, he was just unable to create an atomic bomb.

The debate about Heisenberg's views on the use of atomic weapons is centered on the period from 1939–1942, during which time Germany made a decision not to pursue a nuclear weapons programme. During this period, several events give insight into Heisenberg's role in that decision. At various points evidence during the period suggested that Heisenberg was deliberately steering Germany's research efforts toward developing nuclear energy, rather than nuclear weapons. Some evidence suggests that Heisenberg attempted to communicate these views to the Allies. For example, in April 1941 a German Jewish physicist, Fritz Reiche, arrived in the United States bearing a message from Heisenberg's colleague and friend Fritz Houtermans which was relayed to American officials in the following handwritten note:

"a reliable colleague [Houtermans] who is working at a technical research laboratory asked him [Reiche] to let us know that a large number of German physicists are working intensively on the problem of the uranium bomb under the direction of Heisenberg, that Heisenberg himself tries to delay the work as much as possible, fearing the catastrophic results of a success." (Thomas Powers, Heisenberg's War: The Secret History of the German Bomb.)

Next, there was Heisenberg's visit with an old friend Niels Bohr in occupied Copenhagen in September 1941, the purpose of which has been the subject of great debate. Further, German scientist Hans Peter Jensen visited Niels Bohr in Copenhagen during 1943, of which Bohr wrote that Jensen

"talked [about] efforts to increase the production of heavy water in Norway and hinted in this connection that the German physicists were only considering general technical energy generation."^[9]

Finally, in May 1943, the German spy Erwin Respondek passed a report to Sam Woods, an American consular official in Zurich, that

"the Kaiser Wilhelm group [where Heisenberg was chief of theoretical work in Berlin] purposely raised 'difficulties' to slow down work on the project." (Thomas Powers, Heisenberg's War: The Secret History of the German Bomb.)

According to some Heisenberg critics, the German war efforts stalled in 1940 not because of moral qualms, but because Heisenberg had made a gross overestimate of the "critical mass" of fissionable material (Uranium 235) required for a bomb. An estimate of this amount was crucial to the decision about proceeding with a serious nuclear weapons program because of the enormous difficulty and expense of separating the U235 from the U238 that makes up the vast bulk of natural uranium and the length of time it would take to develop a reactor capable of transmuting the uranium into plutonium. According to some critics, Heisenberg had miscalculated the "critical mass" by not taking into account the "drunkard's walk" trajectory of the slow neutrons emitted, thereby overestimating the amount needed as being in the order of tons, not kilograms as was in fact the case.

However, the contention that Heisenberg had wrongly determined in 1940 that a uranium bomb was not technically feasible is at odds with other evidence. First, during the 1941 visit with Bohr, Heisenberg stated that

"in the preceding years [Heisenberg] had devoted [him]self almost exclusively to the question and were quite certain that it could be done," and that he "felt certain that the war, if it lasted sufficiently long, would be decided with atomic weapons."^[10]

According to Bohr's later notes,

"Heisenberg said explicitly that he did not wish to enter into technical details but that Bohr should understand that he knew what he was talking about as he had spent 2 years working exclusively on this question."

It is unclear why Heisenberg would report to Bohr in 1941 that his research efforts had led him to conclude that a usable nuclear weapon was feasible if, in fact, a miscalculation in 1940 had led him to conclude that it was not feasible.

Second, after the war, Heisenberg and other German physicists were taken by the British to Farm Hall, where their conversations were monitored. The transcripts, however, are ambiguous and subject to debate. At points, it appeared that Heisenberg had miscalculated the critical mass of uranium required for an atomic bomb—covert eavesdropping revealed that, on hearing of the Allied bombing of Hiroshima, he was at first convinced it was a propaganda trick, so sure was he that the critical mass was impracticably large. Some historians have questioned the reliability of the transcripts, as Heisenberg probably knew he was being monitored.

Indeed, there are indications that Heisenberg had made the correct calculation earlier. In June 1942, Heisenberg answered a question about the size of the fissionable core of a bomb by holding his hands to suggest something the size of a football or pineapple, which would have been roughly right. Indeed, after presenting the "incorrect" calculation to the Farm Hall scientists (including those sympathetic to the Nazi regime), one of Heisenberg's confidants, Otto Hahn, questioned Heisenberg's remark that "tons" of U-235 were needed for a bomb, "But tell me why you used to tell me that one needed 50 kilograms of 235 in order to do anything. Now you say one needs two tons."^[11]

Later, Heisenberg told Hahn,

"Quite honestly I have never worked it out as I never believed one could get pure 235. I always knew it could be done with 235 with fast neutrons. That's why 235 only can be used as an explosive. One can never make an explosive with slow neutrons, not even with the heavy water machine [the German nuclear reactor], as then the neutrons only go with thermal speed, with the result that the reaction is so slow that the thing explodes sooner, before the reaction is complete."

Ultimately, upon seeing the reports of the bombing of Hiroshima, Heisenberg told his friend, von Weizsäcker

"I was absolutely convinced of the possibility of our making an uranium engine [reactor] but I never thought that we would make a bomb and at the bottom of my heart I was really glad that it was to be an engine and not a bomb. I must admit that."

Whatever the cause, it is clear that on 4 June 1942, Heisenberg met with German Minister Albert Speer concerning possible uses of Heisenberg's nuclear research, and particularly its potential suitability for the development of nuclear weapons. Notwithstanding Heisenberg's September 1941 report to Bohr that he felt certain nuclear weapons could be constructed and powerful enough to conclude the war if it lasted long enough, during this meeting with Speer he highlighted the technical difficulties and vast time and materials required to separate the uranium needed for the project.

It was this meeting, and Speer's report on it to Hitler, that effectively scuttled any military applications for his work, and limited Heisenberg's work during the remainder of the war to theoretical uses of nuclear energy. As Speer wrote,

"Difficulties were compounded, Heisenberg explained, by the fact that Europe possessed only one cyclotron, and that of minimal capacity. Moreover, it was located in Paris and because of the need for secrecy could not be used to full advantage."

Curiously, albeit perhaps tellingly, Heisenberg did not mention the cyclotron in Copenhagen as a possible source for enriching uranium.

Heisenberg (1946) also proposed an enhancement of Kolmogorov's model of turbulence, to explain the mechanism of transfer of energy from large to small eddies.

[edit] Postwar biography and controversy

In 1956, journalist Robert Jungk published a book titled Brighter Than a Thousand Suns, which painted Heisenberg as having single-handedly and purposely derailed the German project for moral reasons. To justify the claim, in the Danish edition of the book, Jungk printed an excerpt from a personal letter from Heisenberg. The excerpt, however, was taken heavily out of context, and in the full letter Heisenberg was far more demure about whether he had taken a strong moral stance. After reading the excerpt, Bohr was understandably flustered that Heisenberg was (apparently) claiming to have purposely derailed the Nazi bomb project, as it did not match his own perception of Heisenberg's war work at all.

Some historians of science have taken Bohr's draft letters as evidence against Heisenberg's contention that he had met with Bohr to signal that Germany's scientists would not pursue the development of nuclear weapons. Others have argued that Bohr profoundly misunderstood Heisenberg's intentions at the 1941 meeting, and that his reaction to Jungk's work was overly passionate. Significantly, Bohr's draft letters confirm virtually all of Heisenberg's recollection to Jungk of the substance of the meeting. However, as a piece of evidence the letters cannot provide an answer to the question of why Heisenberg broached the topic of nuclear weapons—but not their technical aspects—with Bohr, or whether Bohr formed the correct "impression" of what Heisenberg wanted to say. Heisenberg's motives will most certainly continue to be debated, but it cannot be questioned that he knew Bohr was going to be escaping to the allies when he spoke to him in 1941, and that Heisenberg was risking his life by speaking to anyone about atomic power or atomic weapons.

It is also thought that Italian scientist Gian Carlo Wick approached Heisenberg in January 1944 as an emissary for the OSS as part of Operation Sunrise, to negotiate the capitulation of Nazi scientists to the Allies' Operation Alsos. Allied intelligence through Stockholm continued to sound the alarm about Nazi uranium research right up to war's end, but this was part of Diebner's project, not Heisenberg's.

[edit] References

• David C. Cassidy, "Uncertainty: The Life and Science of Werner Heisenberg", (W. H. Freeman) ISBN 0-7167-2503-7
• James Glanz, "New Twist on Physicist's Role in Nazi Bomb". The New York Times, February 7, 2002.
• Mark Walker, German National Socialism and the Quest for Nuclear Power, 1939-1949 (London: Cambridge University Press, 1990). ISBN 0-521-36413-2 (Hardcover) ISBN 0-521-43804-7 (Paperback)
• Thomas Powers. Heisenberg's War: The Secret History of the German Bomb (Knopf) ISBN 0-394-51411-4 (Hardcover) ISBN 0-316-71623-5 (Paperback)
• Paul Lawrence Rose. Heisenberg and the Nazi Atomic Bomb Project, 1939-1945: A Study in German Culture. University of California Press, 1998, ISBN 0-520-21077-8

• Heisenberg, Werner. Across the frontiers  ; translated from the German by Peter Heath. (Ox Bow Press, 1990) ISBN 0-918024-80-3 (Hardcover) ISBN 0-918024-81-1 (Paperback)
• -- Encounters with Einstein: and other essays on people, places, and particles. Princeton University Press; Reprint edition (October 1, 1989) ISBN 0-691-02433-2
• -- Introduction to the unified field theory of elementary particles. 1966
• -- Natural law and the structure of matter English version by the author. 1970 Warm Wind Books (July 1, 1981) ISBN 0-900615-27-3
• -- Nuclear physics. 1953
• -- et al ,On modern physics. English translation by M. Goodman and J.W. Binns. 1961
• -- Philosophic problems of nuclear science. Translated by F. C. Hayes. 1952; Ox Bow Press (June 1, 1979) ISBN 0-918024-14-5 (Hardcover) ISBN 0-918024-15-3 (Paperback)
• -- Physical principles of the quantum theory, translated into English by Carl Eckart and Frank C. Hoyt ... 1930
• -- Physicist's conception of nature. Translated from the German by Arnold J. Pomerans. Greenwood Press Reprint (March 9, 1970) ISBN 0-8371-3107-3
• -- Physics and beyond; encounters and conversations. Translated from the German by Arnold J. Pomerans. 1971 ISBN 0-04-925020-5
• -- Physics and philosophy : the revolution in modern science, Ed. by Ruth Nanda Anshen, World Perspectives Volume 19, Harper and Brothers Publisher, 1958
• -- Tradition in science. 1981 Continuum Intl Pub Group (November 1, 1982) ISBN 0-8264-0063-9
• -- Two lectures. 1949
• -- et al. Uncertainty principle and foundations of quantum mechanics : a fifty years' survey, edited by William C. Price, Seymour S. Chissick. 1977
• -- The Part and The Whole about his life, his friendship with Bohr, and the evolution of quantum physics.

[edit] External links

• The American Institute of Physics History Center website on Werner Heisenberg Werner Heisenberg photos available from AIP
• 2007 BBC Documentary – "The Atom 1 (of 3): The Clash of the Titans." The last half of the hour has a compelling account of the pained inspiration and rancor surrounding the genesis of his 'Uncertainty Principle' in 1925.
• Göttingen Declaration of the German Nuclear Physicists
• Heisenberg – Bibliography of Writings, Expanded Edition
• Critical Resources: Heisenberg Uncertainty Principle
• Heisenberg - his life & work (including the Uncertainty principle and his controversial role in Nazi Germany's nuclear program) from the American Institute of Physics History Center
• The Nobel Prize in Physics 1932
• About Werner Heisenberg
• Niels Bohr Archive's 2002 release of Bohr-Heisenberg letters
• Werner Heisenberg Official Web Page
• O'Connor, John J; Edmund F. Robertson "Werner Heisenberg". MacTutor History of Mathematics archive.  
• Annotated bibliography for Werner Heisenberg from the Alsos Digital Library for Nuclear Issues
• A fascinating arXiv paper about his life, his physics and his opposition to the Nazi political movement.
• American Institute of Physics History Search: Heisenberg
• Werner Heisenberg 1901 - 1976
• Werner Karl Heisenberg Co-founder of Quantum Mechanics
• Embrace The Horror Werner Heisenberg, the debate of free will versus determinism (half-comedy, article by David Wong)
• History of Twentieth-Century Philosophy of Science by Thomas J. Hickey - with free downloads by chapter for public use.

v • d • e Nobel Laureates in Physics
Jean Perrin (1926) · Arthur Compton / Charles Wilson (1927) · Owen Richardson (1928) · Louis de Broglie (1929) · C. V. Raman (1930) · Werner Heisenberg (1932) · Erwin Schrödinger / Paul Dirac (1933) · James Chadwick (1935) · Victor Hess / Carl Anderson (1936) · Clinton Davisson / George Thomson (1937) · Enrico Fermi (1938) · Ernest Lawrence (1939) · Otto Stern (1943) · Isidor Rabi (1944) · Wolfgang Pauli (1945) · Percy Bridgman (1946) · Edward Appleton (1947) · Patrick Blackett (1948) · Hideki Yukawa (1949) · Cecil Powell (1950)
Complete roster | (1901-1925) | (1926-1950) | (1951-1975) | (1976-2000) | (2001-2025)

Persondata
NAME	Heisenberg, Werner
ALTERNATIVE NAMES	Heisenberg, Werner Karl
SHORT DESCRIPTION	Physicist
DATE OF BIRTH	December 5, 1901
PLACE OF BIRTH	Würzburg, Germany
DATE OF DEATH	February 1, 1976, age 74
PLACE OF DEATH	Munich, Germany