Topic: Physics/Biographies (Page 2)
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π John von Neumann
John von Neumann (; Hungarian: Neumann JΓ‘nos Lajos, pronouncedΒ [ΛnΙjmΙn ΛjaΛnoΚ ΛlΙjoΚ]; December 28, 1903Β β FebruaryΒ 8, 1957) was a Hungarian-American mathematician, physicist, computer scientist, engineer and polymath. Von Neumann was generally regarded as the foremost mathematician of his time and said to be "the last representative of the great mathematicians"; who integrated both pure and applied sciences.
He made major contributions to a number of fields, including mathematics (foundations of mathematics, functional analysis, ergodic theory, representation theory, operator algebras, geometry, topology, and numerical analysis), physics (quantum mechanics, hydrodynamics, and quantum statistical mechanics), economics (game theory), computing (Von Neumann architecture, linear programming, self-replicating machines, stochastic computing), and statistics.
He was a pioneer of the application of operator theory to quantum mechanics in the development of functional analysis, and a key figure in the development of game theory and the concepts of cellular automata, the universal constructor and the digital computer.
He published over 150 papers in his life: about 60 in pure mathematics, 60 in applied mathematics, 20 in physics, and the remainder on special mathematical subjects or non-mathematical ones. His last work, an unfinished manuscript written while he was in hospital, was later published in book form as The Computer and the Brain.
His analysis of the structure of self-replication preceded the discovery of the structure of DNA. In a short list of facts about his life he submitted to the National Academy of Sciences, he stated, "The part of my work I consider most essential is that on quantum mechanics, which developed in GΓΆttingen in 1926, and subsequently in Berlin in 1927β1929. Also, my work on various forms of operator theory, Berlin 1930 and Princeton 1935β1939; on the ergodic theorem, Princeton, 1931β1932."
During World War II, von Neumann worked on the Manhattan Project with theoretical physicist Edward Teller, mathematician StanisΕaw Ulam and others, problem solving key steps in the nuclear physics involved in thermonuclear reactions and the hydrogen bomb. He developed the mathematical models behind the explosive lenses used in the implosion-type nuclear weapon, and coined the term "kiloton" (of TNT), as a measure of the explosive force generated.
After the war, he served on the General Advisory Committee of the United States Atomic Energy Commission, and consulted for a number of organizations, including the United States Air Force, the Army's Ballistic Research Laboratory, the Armed Forces Special Weapons Project, and the Lawrence Livermore National Laboratory. As a Hungarian Γ©migrΓ©, concerned that the Soviets would achieve nuclear superiority, he designed and promoted the policy of mutually assured destruction to limit the arms race.
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- "John von Neumann" | 2015-06-26 | 20 Upvotes 3 Comments
π Ettore Majorana
Ettore Majorana (, Italian: [ΛΙttore majoΛraΛna]; born on 5 August 1906 β likely dying in or after 1959) was an Italian theoretical physicist who worked on neutrino masses. On 25Β March 1938, he disappeared under mysterious circumstances after purchasing a ticket to travel by ship from Naples to Palermo.
The Majorana equation and Majorana fermions are named after him. In 2006, the Majorana Prize was established in his memory.
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- "Ettore Majorana" | 2024-08-03 | 16 Upvotes 7 Comments
π James Dewar
Sir James Dewar (20 September 1842 β 27 March 1923) was a Scottish chemist and physicist. He is best known for his invention of the vacuum flask, which he used in conjunction with research into the liquefaction of gases. He also studied atomic and molecular spectroscopy, working in these fields for more than 25 years.
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- "James Dewar" | 2020-04-01 | 20 Upvotes 2 Comments
π Bruno Pontecorvo
Bruno Pontecorvo (Italian:Β [ponteΛkΙrvo]; Russian: ΠΡΡΜΠ½ΠΎ ΠΠ°ΠΊΡΠΈΜΠΌΠΎΠ²ΠΈΡ ΠΠΎΠ½ΡΠ΅ΠΊΠΎΜΡΠ²ΠΎ, Bruno Maksimovich Pontecorvo; 22 August 1913 β 24 September 1993) was an Italian and Soviet nuclear physicist, an early assistant of Enrico Fermi and the author of numerous studies in high energy physics, especially on neutrinos. A convinced communist, he defected to the Soviet Union in 1950, where he continued his research on the decay of the muon and on neutrinos. The prestigious Pontecorvo Prize was instituted in his memory in 1995.
The fourth of eight children of a wealthy Jewish-Italian family, Pontecorvo studied physics at the University of Rome La Sapienza, under Fermi, becoming the youngest of his Via Panisperna boys. In 1934 he participated in Fermi's famous experiment showing the properties of slow neutrons that led the way to the discovery of nuclear fission. He moved to Paris in 1934, where he conducted research under Irène and Frédéric Joliot-Curie. Influenced by his cousin, Emilio Sereni, he joined the French Communist Party, as did his sisters Giuliana and Laura and brother Gillo. The Italian Fascist regime's 1938 racial laws against Jews caused his family members to leave Italy for Britain, France and the United States.
When the German Army closed in on Paris during the Second World War, Pontecorvo, his brother Gillo, cousin Emilio Sereni and Salvador Luria fled the city on bicycles. He eventually made his way to Tulsa, Oklahoma, where he applied his knowledge of nuclear physics to prospecting for oil and minerals. In 1943, he joined the British Tube Alloys team at the Montreal Laboratory in Canada. This became part of the Manhattan Project to develop the first atomic bombs. At Chalk River Laboratories, he worked on the design of the nuclear reactor ZEEP, the first reactor outside of the United States that went critical in 1945, followed by the NRX reactor in 1947. He also looked into cosmic rays, the decay of muons, and what would become his obsession, neutrinos. He moved to Britain in 1949, where he worked for the Atomic Energy Research Establishment at Harwell.
After his defection to the Soviet Union in 1950, he worked at the Joint Institute for Nuclear Research (JINR) in Dubna. He had proposed using chlorine to detect neutrinos. In a 1959 paper, he argued that the electron neutrino (
Ξ½
e) and the muon neutrino (
Ξ½
ΞΌ) were different particles. Solar neutrinos were detected by the Homestake Experiment, but only between one third and one half of the predicted number were found. In response to this solar neutrino problem, he proposed a phenomenon known as neutrino oscillation, whereby electron neutrinos became muon neutrinos. The existence of the oscillations was finally established by the Super-Kamiokande experiment in 1998. He also predicted in 1958 that supernovae would produce intense bursts of neutrinos, which was confirmed in 1987 when Supernova SN1987A was detected by neutrino detectors.
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- "Bruno Pontecorvo" | 2021-10-27 | 13 Upvotes 4 Comments
π Religious Views of Isaac Newton
Isaac Newton (4 January 1643 β 31 March 1727) was considered an insightful and erudite theologian by his Protestant contemporaries. He wrote many works that would now be classified as occult studies, and he wrote religious tracts that dealt with the literal interpretation of the Bible. He kept his heretical beliefs private.
Newton's conception of the physical world provided a model of the natural world that would reinforce stability and harmony in the civic world. Newton saw a monotheistic God as the masterful creator whose existence could not be denied in the face of the grandeur of all creation. Although born into an Anglican family, and a devout but unorthodox Christian, by his thirties Newton held a Christian faith that, had it been made public, would not have been considered orthodox by mainstream Christians. Scholars now consider him a Nontrinitarian Arian.
He may have been influenced by Socinian christology.
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- "Religious Views of Isaac Newton" | 2022-02-11 | 13 Upvotes 1 Comments
π Elizabeth Fleischman
Elizabeth Fleischman-Aschheim (nΓ©e Fleischman 5 March 1867 β 3 August 1905) was an American radiographer who is considered an X-ray pioneer. Fleischman was the first woman to die as a result of X-ray radiation exposure.