Freeman Dyson

from Wikipedia, the free encyclopedia
Freeman Dyson (2005)

Freeman John Dyson (born December 15, 1923 in Crowthorne , Berkshire , † February 28, 2020 in Princeton , New Jersey ) was a British - American physicist and mathematician .

education

Freeman Dyson - a son of the English composer George Dyson - studied mathematics in Cambridge with Godfrey Harold Hardy , where he received his bachelor's degree in 1945. His studies were interrupted during World War II from 1943 to 45 when he worked as a civilian analyst at the British Bomber Command , where he was responsible for the statistical analysis of casualties.

Dyson published in the 1940s a. a. mathematical work on the theory of partitions and the Diophantine approximations from the context of the Thue-Siegel-Roth theorem . After the war he switched to theoretical physics and started a doctoral degree. With a Commonwealth scholarship he went to the USA, where he did research at Cornell University from 1947 with Hans Bethe . There he met Richard Feynman . Dyson studied his second year in the USA under Robert Oppenheimer at the Institute for Advanced Study . From 1949 to 1951 he worked as a research fellow at the University of Birmingham .

Although he did not formally complete his dissertation (but later received numerous honorary doctorates), he was appointed to Cornell University as a physics professor in 1951 - presumably because of his contributions to quantum electrodynamics . Oppenheimer made him a permanent member of the IAS in Princeton in 1953. In 1957 he became a US citizen.

plant

Quantum physics

In the post-war years Dyson dealt with the proof of the equivalence of the two formulations of quantum electrodynamics (QED) that existed at that time, the descriptive diagram formulation of Richard Feynman and the variation approach of Julian Schwinger and Shinichirō Tomonaga . His essays contributed significantly to the acceptance of Feynman's formulation of QED. The so-called Dyson time order operator, which plays a fundamental role in quantum mechanics, is named after him.

After his success in QED, he wanted to apply similar diagram methods as a professor at Cornell University from 1950 to the meson theory of strong interactions and especially to the scattering experiments of mesons on nucleons carried out in Chicago under the direction of Enrico Fermi . Despite seemingly good agreement with the experiment, a visit to Fermi in Chicago brought him disillusionment. The latter advised him not to deal with it any further, the theory would not give a clear physical picture and would not be mathematically consistent, the successes were only the result of parameters skillfully adapted to the experiments. Dyson then turned to solid-state physics.

In 1967/68 he and Andrew Lenard (later expanded by Elliott Lieb and Walter Thirring ) showed that the stability of ordinary matter is essentially based on the Pauli principle of fermions (and not on the electrostatic repulsion of electrons or protons).

He also examined the question of the fundamental observability of gravitons .

space

From 1957 to 1961 he worked on the Orion project , which examined the possibilities of interstellar space flights using a nuclear drive . A prototype using conventional explosives was tested, but the project was discontinued after the use of nuclear weapons in the atmosphere was banned by the Treaty banning nuclear weapons tests in the atmosphere, in space and underwater . In 1957 he was on the development team for the TRIGA reactor , which was planned as an inherently safe, small nuclear reactor.

In one of his scientific papers, Dyson argued that an advanced civilization could completely surround a star with structure to maximize energy production (see Dyson Sphere ). But even if this were successful and light of all wavelengths could be used, the structure would give off thermal radiation in the infrared range . He concluded that one way to find extraterrestrial life was to look for large objects that radiate in the infrared.

His essay Time without end - physics and biology in an open universe in Reviews of modern physics, Vol. 51, 1979, in which he examines the future of life in an ever-expanding universe, is also known.

Dyson has also proposed constructing a so-called Dyson tree, a genetically modified plant that would be able to grow on a comet . He suspected that comets, hollowed out and given a breathable atmosphere , could serve as habitat for humans in the outer solar system .

Mathematical physics

Dyson is best known as a mathematical physicist. For example, he dealt with the theory of interacting spin waves with Dyson bosons, which he introduced, and made important contributions to the theory of random matrices . In the early 1970s, in a conversation with the number theorist Montgomery, he established their relationship to the distribution of zeros in the Riemann zeta function .

In Missed opportunities in the Bulletin American Mathematical Society 1972 (his Gibbs Lecture ) he critically examines the lack of communication between physicists and mathematicians, which has often been a history, and in Unfashionable pursuits in the Mathematical Intelligencer 1983 he breaks a lance for unconventional research directions (e.g. George Green , Hermann Graßmann ).

philosophy

Dyson has also repeatedly dealt with philosophical problems. For example, in his book Infinite in all Directions , he suggests a three-level metaphysics of mind: “The universe shows evidence of the operations of mind on three levels. The first level is the level of elementary physical processes in quantum mechanics. [...] The second level at which we detect the operations of mind is the level of direct human experience. [...] [I] t is reasonable to believe in the existence of a third level of mind, a mental component of the universe. If we believe in this mental component and call it God, then we can say that we are small pieces of God's mental apparatus ”(p. 297).

Dyson at IAS 2007

In his book Origins of Life he argues, contrary to the prevailing opinion, that proteins and cells existed before nucleic acids (stage of the garbage bag world ). A metabolism based on mutually catalyzing reactions developed within the cell. Ribonucleic acid (RNA) initially arose as a parasitic self-reproducing reaction similar to viruses and was linked to the cell metabolism in a kind of symbiosis in the next step.

Climate change

Most recently he has dealt with questions about global warming and in particular the influence of the increased carbon dioxide concentration in the atmosphere on it. Probably based on his Dyson tree, he hoped for the development of genetically modified trees in the future, which - serving as CO 2 sinks - should be cultivated over large areas of the earth. Dyson was skeptical of model-based climate predictions.

Personal

Freeman Dyson is the father of journalist Esther Dyson and science historian George Dyson . Both come from his marriage (1950 to the divorce in 1958) with the mathematician Verena Huber-Dyson (1923-2016). He died at the age of 96 from complications from a fall three days earlier in the Institute for Advanced Study cafeteria.

Memberships

Awards

Honors

Publications

  • Selected papers with commentary. American Mathematical Society 1996 (Commentary by Dyson).
  • Scientist as rebel. New York Review Books 2006.
  • Disturbing the universe. Harper and Row, New York 1979, ISBN 0-06-011108-9 , Basic Books 2001 (autobiographical articles).
    • German: Interior views: memories of the future. Birkhauser, Basel / Boston / Stuttgart 1981, ISBN 3-7643-1200-9 .
  • Infinite in all directions. Harper and Row 1988 (Gifford Lectures in Aberdeen).
  • Time without end - physics and biology in an open universe. In: Reviews of modern physics. Vol. 51, 1979.
    • Time without end. Physics and biology in an open universe. Translated by Rolf Herken. Brinkmann & Bose, Berlin 1989, ISBN 3-922660-39-8 . (Translation of the article Time without end. Reviews of Modern Physics, Volume 51, 1979).
  • From Eros to Gaia. Pantheon Books, New York 1992.
  • Imagined worlds. Harvard University Press, 1997.
  • Origins of Life. Cambridge University Press, 1985, 1999.
  • The Sun, the Genome and the Internet: Tools of Scientific Revolutions. Oxford University Press, 1999.
    • Freeman J. Dyson: The Sun, the Genome, and the Internet. Scientific innovation and the technologies of the future . S. Fischer, Frankfurt am Main 2000, ISBN 3-10-015335-9 .
  • Birds and Frogs. Selected Papers 1990-2014. World Scientific, 2015.
  • Birds and frogs. e-enterprise, Lemgo 2014.
  • Dyson quantum field theory. The world famous introduction by one of the fathers of QED. Freeman Dyson's famous lecture for the first time in German. Springer Spectrum, Berlin & Heidelberg 2014. ISBN 978-3-642-37677-1 (print); ISBN 978-3-642-37678-8 (eBook).
  • A many-colored glass. Reflections on the place of life in the universe. University of Virginia Press, 2007.
  • The Scientist as Rebel. New York Review of Books 2006 (New York Review of Books 1996-2006).
  • Dreams of Earth and Sky. New York Review of Books 2015 (Reviews in New York Review of Books 2006–2014).
  • Bombs and Poetry. The Tanner Lectures on Human Values, Oxford 1982. In: Sterling McMurrin (Ed.): The Tanner Lectures on Human Values ​​IV. Oxford University Press, 1983.
  • Maker of Patterns: An Autobiography Through Letters. Liveright Publishing Corporation, New York 2018, ISBN 978-0-87140-386-5 .

literature

Web links

Commons : Freeman Dyson  - collection of images, videos and audio files

Individual evidence

  1. ↑ See Disturbing the universe.
  2. ^ The Editors of Encyclopaedia Britannica: Freeman Dyson, American physicist. In: Encyclopaedia Britannica. February 28, 2020, accessed April 22, 2020 .
  3. ^ Susan Higgins: Freeman J. Dyson - Biography (detailed). In: sns.ias.edu. IAS, May 9, 2013, accessed April 22, 2020 .
  4. ^ John Timmer: The man behind the sphere, Freeman Dyson, is dead at 96. In: arstechnica.com. Condé Nast, February 28, 2020, accessed April 22, 2020 .
  5. ^ Dyson: Radiation theories of Schwinger, Tomonaga and Feynman. In: Physical Review. Vol. 75, 1949, p. 486, and The S-Matrix in Quantum Electrodynamics. S. 1736. Reprinted in Schwinger ed. Selected papers on QED. Dover. His Lectures on Advanced Quantum Mechanics, Cornell 1951, are online.
  6. ↑ See e.g. B. Mathematical structure of quantum mechanics .
  7. ^ Dyson: A meeting with Enrico Fermi. In: Nature. Vol. 427, January 22, 2004.
  8. ^ Dyson, Lenard: Stability of matter. Part 1, J. Math. Phys., Volume 8, 1967, pp. 423-434, Volume 9, 1968, pp. 698-711.
  9. ^ Lieb, Thirring: Bound for the Kinetic Energy of Fermions Which Proves the Stability of Matter. Phys. Rev. Lett., Vol. 35, 1975, pp. 687-689.
  10. ↑ Dyson: Is a graviton detectable? In: International Journal of Modern Physics. A, Volume 28, 2013.
  11. ↑ FJ Dyson: Interstellar Transport. In: Physics Today. October 1968, pp. 41–45, PDF, accessed on November 7, 2011.
  12. ↑ See his report in Disturbing the universe and Dyson: Interstellar transport. In: physics today. October 1968.
  13. ^ Dyson: Search for artificial sources of infrared radiation. In: Science. Vol. 131, 1960, 1667, also in Cameron: Interstellar communication and The search for extraterrestrial technology. In: Marshak ed .: Perspectives in modern physics. 1966 (Bethe Festschrift).
  14. ↑ Physical Review. Vol. 102, 1956, p. 1217.
  15. ^ Susan Mazur: An Interview With Freeman Dyson on the Origins of Life on Earth. Counterpunch, June 27, 2012. He is still sticking to his theory in 2012 and sees only the increasingly clear indications of an original RNA world as the main progress since the publication of his book.
  16. ^ Freeman Dyson: The Question of Global Warming. In: The New York Review of Books. Volume 55, Number 10, June 12, 2008.
  17. ↑ George Johnson: Freeman Dyson, Math Genius Turned Technological Visionary, Dies at 96. In: nytimes.com. The New York Times Company, February 28, 2020, accessed April 21, 2020 .
  18. ^ Foreign members of the Russian Academy of Sciences since 1724. Freeman John Dyson. In: ras.ru. Russian Academy of Sciences, accessed August 23, 2015 (in Russian).
  19. ^ Maker of Patterns. An Autobiography Through Letters. (Video 43:47) In: ias.edu. 2018, accessed March 1, 2020 .
  20. ↑ Do what you want to do. In: FAZ . April 25, 2013, p. 28.
personal data
SURNAME Dyson, Freeman
ALTERNATIVE NAMES Dyson, Freeman John (full name)
BRIEF DESCRIPTION British-American physicist and mathematician
DATE OF BIRTH December 15, 1923
PLACE OF BIRTH Crowthorne
DATE OF DEATH February 28, 2020
Place of death Princeton