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Freeman Dyson (2005)
Freeman John Dyson (15 December 1923 – 28 February 2020) was a British-American theoretical physicist and mathematician known for his works in quantum field theory, astrophysics, random matrices, mathematical formulation of quantum mechanics, condensed matter physics, nuclear physics, and engineering. He was professor emeritus in the Institute for Advanced Study in Princeton and a member of the board of sponsors of the ''Bulletin of the Atomic Scientists''. Dyson originated several concepts that bear his name, such as Dyson's transform, a fundamental technique in additive number theory, which he developed as part of his proof of Mann's theorem; the Dyson tree, a hypothetical genetically engineered plant capable of growing in a comet; the Dyson series, a perturbative series where each term is represented by Feynman diagrams; the Dyson sphere, a thought experiment that attempts to explain how a space-faring civilization would meet its energy requirements with a hypotheti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long Now Seminar
The Long Now Foundation, established in 1996, is an American non-profit organization based in San Francisco that seeks to start and promote a long-term cultural institution. It aims to provide a counterpoint to what it views as today's "faster/cheaper" mindset and to promote "slower/better" thinking. The Long Now Foundation hopes to "creatively foster responsibility" in the framework of the next 10,000 years. In a manner somewhat similar to the Holocene calendar, the foundation uses 5-digit dates to address the Year 10,000 problem (e.g., by writing the current year "0" rather than ""). The organisation's logo is , a capital X with an overline, a representation of 10,000 in Roman numerals. Projects The foundation has several ongoing projects, including a 10,000-year clock known as the ''Clock of the Long Now'', the ''Rosetta Project'', the ''Long Bet Project'', the open source ''Timeline Tool'' (also known as Longviewer), the ''Long Server'' and a monthly seminar series. Clo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crank Of A Partition
In number theory, the crank of a partition of an integer is a certain integer associated with the partition. The term was first introduced without a definition by Freeman Dyson in a 1944 paper published in Eureka, a journal published by the Mathematics Society of Cambridge University. Dyson then gave a list of properties this yet-to-be-defined quantity should have. In 1988, George E. Andrews and Frank Garvan discovered a definition for the crank satisfying the properties hypothesized for it by Dyson. Dyson's crank Let ''n'' be a non-negative integer and let ''p''(''n'') denote the number of partitions of ''n'' (''p''(0) is defined to be 1). Srinivasa Ramanujan in a paper published in 1918 stated and proved the following congruences for the partition function ''p''(''n''), since known as Ramanujan congruences. * ''p''(5''n'' + 4) ≡ 0 (mod 5) * ''p''(7''n'' + 5) ≡ 0 (mod 7) * ''p''(11''n'' + 6) ≡ 0 (mod 11) These congruences imply that partitions of numbers of the form 5'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hughes Medal
The Hughes Medal is awarded by the Royal Society of London "in recognition of an original discovery in the physical sciences, particularly electricity and magnetism or their applications". Named after David E. Hughes, the medal is awarded with a gift of £1000. The medal was first awarded in 1902 to J. J. Thomson "for his numerous contributions to electric science, especially in reference to the phenomena of electric discharge in gases", and has since been awarded over one-hundred times. Unlike other Royal Society medals, the Hughes Medal has never been awarded to the same individual more than once. The medal has on occasion been awarded to multiple people at a time; in 1938 it was won by John Cockcroft and Ernest Walton "for their discovery that nuclei could be disintegrated by artificially produced bombarding particles", in 1981 by Peter Higgs and Tom Kibble "for their international contributions about the spontaneous breaking of fundamental symmetries in elementary-particle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lorentz Medal
Lorentz Medal is a distinction awarded every four years by the Royal Netherlands Academy of Arts and Sciences. It was established in 1925 on the occasion of the 50th anniversary of the doctorate of Hendrik Lorentz. The medal is given for important contributions to theoretical physics, though in the past there have been some experimentalists among its recipients. The first winner, Max Planck, was personally selected by Lorentz. Eleven of the 23 award winners later received a Nobel Prize. The Lorentz medal is ranked fifth in a list of most prestigious international academic awards in physics. Recipients See also * List of physics awards This list of physics awards is an index to articles about notable awards for physics. The list includes lists of awards by the American Physical Society of the United States, and of the Institute of Physics of the United Kingdom, followed by a li ... References {{reflist, 2 Physics awards Dutch honorary society awards Science and te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dannie Heineman Prize For Mathematical Physics
Dannie Heineman Prize for Mathematical Physics is an award given each year since 1959 jointly by the American Physical Society and American Institute of Physics. It is established by the Heineman Foundation in honour of Dannie Heineman. As of 2010, the prize consists of US$10,000 and a certificate citing the contributions made by the recipient plus travel expenses to attend the meeting at which the prize is bestowed. Past Recipients Source: American Physical Society *2022 Antti Kupiainen and Krzysztof Gawędzki *2021 Joel Lebowitz *2020 Svetlana Jitomirskaya *2019 T. Bill Sutherland, Francesco Calogero and Michel Gaudin *2018 Barry Simon *2017 Carl M. Bender *2016 Andrew Strominger and Cumrun Vafa *2015 Pierre Ramond *2014 Gregory W. Moore *2013 Michio Jimbo and Tetsuji Miwa *2012 Giovanni Jona-Lasinio *2011 Herbert Spohn *2010 Michael Aizenman *2009 Carlo Becchi, , Raymond Stora and Igor Tyutin *2008 Mitchell Feigenbaum *2007 Juan Maldacena and Joseph Polchinski *2006 Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dyson Sphere
A Dyson sphere is a hypothetical megastructure that completely encompasses a star and captures a large percentage of its solar power output. The concept is a thought experiment that attempts to explain how a spacefaring civilization would meet its energy requirements once those requirements exceed what can be generated from the home planet's resources alone. Because only a tiny fraction of a star's energy emissions reaches the surface of any orbiting planet, building structures encircling a star would enable a civilization to harvest far more energy. The first contemporary description of the structure was by Olaf Stapledon in his science fiction novel '' Star Maker'' (1937), in which he described "every solar system... surrounded by a gauze of light-traps, which focused the escaping solar energy for intelligent use". The concept was later popularized by Freeman Dyson in his 1960 paper "Search for Artificial Stellar Sources of Infrared Radiation". Dyson speculated that such stru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-nuclear Movement In The United States
The anti-nuclear movement in the United States consists of more than 80 anti-nuclear groups that oppose nuclear power, nuclear weapons, and/or uranium mining. These have included the Abalone Alliance, Clamshell Alliance, Committee for Nuclear Responsibility, Nevada Desert Experience, Nuclear Information and Resource Service, Physicians for Social Responsibility, Plowshares Movement, Women Strike for Peace, and Women's International League for Peace and Freedom. Some fringe aspects of the anti-nuclear movement have delayed construction or halted commitments to build some new nuclear plants, and have pressured the Nuclear Regulatory Commission to enforce and strengthen the safety regulations for nuclear power plants. Most groups in the movement focus on nuclear weapons. Anti-nuclear protests reached a peak in the 1970s and 1980s and grew out of the environmental movement. Campaigns that captured national public attention involved the Calvert Cliffs Nuclear Power Plant, Seabrook ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRIGA
TRIGA (Training, Research, Isotopes, General Atomics) is a class of nuclear research reactor designed and manufactured by General Atomics. The design team for TRIGA, which included Edward Teller, was led by the physicist Freeman Dyson. Design TRIGA is a swimming pool reactor that can be installed without a containment building, and is designed for research and testing use by scientific institutions and universities for purposes such as undergraduate and graduate education, private commercial research, non-destructive testing and isotope production. The TRIGA reactor uses uranium zirconium hydride (UZrH) fuel, which has a large, prompt negative fuel temperature coefficient of reactivity, meaning that as the temperature of the core increases, the reactivity rapidly decreases. Because of this unique feature, it has been safely pulsed at a power of up to 22,000 megawatts. The hydrogen in the fuel is bound in the uranium zirconium hydride crystal structure with a vibrational energ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Project Orion (nuclear Propulsion)
Project Orion was a study conducted between the 1950s and 1960s by the United States Air Force, DARPA, and NASA for the purpose of identifying the efficacy of a starship directly propelled by a series of explosions of atomic bombs behind the craft—nuclear pulse propulsion. Early versions of this vehicle were proposed to take off from the ground; later versions were presented for use only in space. Six non-nuclear tests were conducted using models. The project was eventually abandoned for multiple reasons, including the Partial Test Ban Treaty, which banned nuclear explosions in space, and concerns over nuclear fallout. The idea of rocket propulsion by combustion of explosive substance was first proposed by Russian explosives expert Nikolai Kibalchich in 1881, and in 1891 similar ideas were developed independently by German engineer Hermann Ganswindt. Robert A. Heinlein mentions powering spaceships with nuclear bombs in his 1940 short story "Blowups Happen". Real life propos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helios (propulsion System)
Helios is a design for a spacecraft propulsion system such that small (0.1 kiloton) nuclear bombs would be detonated in a chamber roughly in diameter. Water would be injected into the chamber, super-heated by the explosion and expelled for thrust. It was a precursor concept to the Orion project. Like Orion, it would have achieved constant acceleration through rapid "pulsed" operation. This design would have yielded a specific impulse of about 1150 seconds (compared to a modern chemical rocket's 450 seconds). However, a number of technical problems existed, most prominently how to keep the combustion chamber from exploding from the great pressures of the atomic detonations. The Helios propulsion system was originally conceived by Freeman Dyson. See also *Operation Plumbbob Operation Plumbbob was a series of nuclear tests that were conducted between May 28 and October 7, 1957, at the Nevada Test Site, following ''Project 57'', and preceding '' Project 58/58A''. Background ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Electrodynamics
In particle physics, quantum electrodynamics (QED) is the relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and special relativity is achieved. QED mathematically describes all phenomena involving electrically charged particles interacting by means of exchange of photons and represents the quantum counterpart of classical electromagnetism giving a complete account of matter and light interaction. In technical terms, QED can be described as a perturbation theory of the electromagnetic quantum vacuum. Richard Feynman called it "the jewel of physics" for its extremely accurate predictions of quantities like the anomalous magnetic moment of the electron and the Lamb shift of the energy levels of hydrogen. History The first formulation of a quantum theory describing radiation and matter interaction is attributed to British scientist Paul Dirac, who ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-replicating Machine
A self-replicating machine is a type of autonomous robot that is capable of reproducing itself autonomously using raw materials found in the environment, thus exhibiting self-replication in a way analogous to that found in nature. The concept of self-replicating machines has been advanced and examined by Homer Jacobson, Edward F. Moore, Freeman Dyson, John von Neumann, Konrad Zuse and in more recent times by K. Eric Drexler in his book on nanotechnology, ''Engines of Creation'' (coining the term clanking replicator for such machines) and by Robert Freitas and Ralph Merkle in their review ''Kinematic Self-Replicating Machines'' which provided the first comprehensive analysis of the entire replicator design space. The future development of such technology is an integral part of several plans involving the mining of moons and asteroid belts for ore and other materials, the creation of lunar factories, and even the construction of solar power satellites in space. The von Neumann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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