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Wigner
Eugene Paul "E. P." Wigner ( hu, Wigner Jenő Pál, ; November 17, 1902 – January 1, 1995) was a Hungarian-American theoretical physicist who also contributed to mathematical physics. He received the Nobel Prize in Physics in 1963 "for his contributions to the theory of the atomic nucleus and the elementary particles, particularly through the discovery and application of fundamental symmetry principles". A graduate of the Technical University of Berlin, Wigner worked as an assistant to Karl Weissenberg and Richard Becker at the Kaiser Wilhelm Institute in Berlin, and David Hilbert at the University of Göttingen. Wigner and Hermann Weyl were responsible for introducing group theory into physics, particularly the theory of symmetry in physics. Along the way he performed ground-breaking work in pure mathematics, in which he authored a number of mathematical theorems. In particular, Wigner's theorem is a cornerstone in the mathematical formulation of quantum mechanics. He is als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wigner's Friend
Wigner's friend is a thought experiment in theoretical quantum physics, first conceived by the physicist Eugene Wigner in 1961, Reprinted in and further developed by David Deutsch in 1985. The scenario involves an indirect observation of a Measurement in quantum mechanics, quantum measurement: An Observer (quantum physics), observer W observes another observer F who performs a Measurement in quantum mechanics, quantum measurement on a physical system. The two observers then formulate a statement about the physical system's Quantum state, state after the measurement according to the laws of quantum theory. However, in most of the Interpretations of quantum mechanics, interpretations of quantum mechanics, the resulting statements of the two observers contradict each other. This reflects a seeming incompatibility of two laws in quantum theory: the deterministic and continuous Schrödinger equation, time evolution of the state of a closed system and the nondeterministic, discontinuous W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wigner Semicircle Distribution
The Wigner semicircle distribution, named after the physicist Eugene Wigner, is the probability distribution on minus;''R'', ''R''whose probability density function ''f'' is a scaled semicircle (i.e., a semi-ellipse) centered at (0, 0): :f(x)=\sqrt\, for −''R'' ≤ ''x'' ≤ ''R'', and ''f''(''x'') = 0 if '', x, '' > ''R''. It is also a scaled beta distribution: if ''Y'' is beta-distributed with parameters α = β = 3/2, then ''X'' = 2''RY'' – ''R'' has the Wigner semicircle distribution. The distribution arises as the limiting distribution of eigenvalues of many random symmetric matrices as the size of the matrix approaches infinity. The distribution of the spacing between eigenvalues is addressed by the similarly named Wigner surmise. General properties The Chebyshev polynomials of the third kind are orthogonal polynomials with respect to the Wigner semicircle distribution. For positive integers ''n'', the 2''n''-th moment of this distribution is :E(X^)=\l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
László Rátz
László Rátz (9 April 1863 in Sopron – 30 September 1930 in Budapest) was a Hungarian mathematics high school teacher best known for educating such people as John von Neumann and Nobel laureate Eugene Wigner. He was a legendary teacher of "Budapest-Fasori Evangélikus Gimnázium", the Budapest Lutheran Gymnasium, a famous secondary school in Budapest in Hungary. Biography He was born on 9 April 1863 in Sopron, a city in Hungary on the Austrian border, near the Lake Neusiedl/Lake Fertő. His father, Ágost Rátz, was a hardware merchant and ironmonger, and his mother was Emma Töpler of Danube Swabian origin. He graduated from the Lutheran Grammar School of Sopron in 1882. The courses of study for elementary and middle school the first two years are not available. He was a student in the Hungarian royal state grammar school, "Főreáliskola in Sopron" between 1875 and 1880, now Széchenyi István Gimnázium (Sopron). From 1880 to 1882 he studied at the Sopron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bargmann–Wigner Equations
:''This article uses the Einstein summation convention for tensor/spinor indices, and uses hats for quantum operators. In relativistic quantum mechanics and quantum field theory, the Bargmann–Wigner equations describe free particles with non-zero mass and arbitrary spin , an integer for bosons () or half-integer for fermions (). The solutions to the equations are wavefunctions, mathematically in the form of multi-component spinor fields. They are named after Valentine Bargmann and Eugene Wigner. History Paul Dirac first published the Dirac equation in 1928, and later (1936) extended it to particles of any half-integer spin before Fierz and Pauli subsequently found the same equations in 1939, and about a decade before Bargman, and Wigner. Eugene Wigner wrote a paper in 1937 about unitary representations of the inhomogeneous Lorentz group, or the Poincaré group. Wigner notes Ettore Majorana and Dirac used infinitesimal operators applied to functions. Wigner classifies repre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wigner–Eckart Theorem
The Wigner–Eckart theorem is a theorem of representation theory and quantum mechanics. It states that matrix elements of spherical tensor operators in the basis of angular momentum eigenstates can be expressed as the product of two factors, one of which is independent of angular momentum orientation, and the other a Clebsch–Gordan coefficient. The name derives from physicists Eugene Wigner and Carl Eckart, who developed the formalism as a link between the symmetry transformation groups of space (applied to the Schrödinger equations) and the laws of conservation of energy, momentum, and angular momentum.Eckart Biography – The National Academies Press. Mathematically, the Wigner–Eckart theorem is generally stated in the following way. Given a tensor operator and two states of angular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wigner D-matrix
The Wigner D-matrix is a unitary matrix in an irreducible representation of the groups SU(2) and SO(3). It was introduced in 1927 by Eugene Wigner, and plays a fundamental role in the quantum mechanical theory of angular momentum. The complex conjugate of the D-matrix is an eigenfunction of the Hamiltonian of spherical and symmetric rigid rotors. The letter stands for ''Darstellung'', which means "representation" in German. Definition of the Wigner D-matrix Let be generators of the Lie algebra of SU(2) and SO(3). In quantum mechanics, these three operators are the components of a vector operator known as ''angular momentum''. Examples are the angular momentum of an electron in an atom, electronic spin, and the angular momentum of a rigid rotor. In all cases, the three operators satisfy the following commutation relations, : _x,J_y= i J_z,\quad _z,J_x= i J_y,\quad _y,J_z= i J_x, where ''i'' is the purely imaginary number and Planck's constant has been set equal to one. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frederick Seitz
Frederick Seitz (July 4, 1911 – March 2, 2008) was an American physicist and a pioneer of solid state physics and lobbyist. Seitz was the 4th president of Rockefeller University from 1968–1978, and the 17th president of the United States National Academy of Sciences from 1962–1969. Seitz was the recipient of the National Medal of Science, NASA's Distinguished Public Service Award, and other honors. He founded the Frederick Seitz Materials Research Laboratory at the University of Illinois at Urbana–Champaign and several other material research laboratories across the United States. Seitz was also the founding chairman of the George C. Marshall Institute, a tobacco industry consultant, and a prominent climate change denier. Background and personal life Born in San Francisco on July 4, 1911, Seitz graduated from Lick-Wilmerding High School in the middle of his senior year, and went on to study physics at Stanford University obtaining his bachelor's degree in three years, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Technical University Of Berlin
The Technical University of Berlin (official name both in English and german: link=no, Technische Universität Berlin, also known as TU Berlin and Berlin Institute of Technology) is a public research university located in Berlin, Germany. It was the first German university to adopt the name "Technische Universität" (Technical University). The university alumni and professor list includes several US National Academies members, two National Medal of Science laureates and ten Nobel Prize laureates. TU Berlin is a member of TU9, an incorporated society of the largest and most notable German institutes of technology and of the Top International Managers in Engineering network, which allows for student exchanges between leading engineering schools. It belongs to the Conference of European Schools for Advanced Engineering Education and Research. The TU Berlin is home of two innovation centers designated by the European Institute of Innovation and Technology. The university is labe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michael Polanyi
Michael Polanyi (; hu, Polányi Mihály; 11 March 1891 – 22 February 1976) was a Hungarian-British polymath, who made important theoretical contributions to physical chemistry, economics, and philosophy. He argued that positivism supplies an imperfect account of knowing as no observer is perfectly impartial. His wide-ranging research in physical science included chemical kinetics, x-ray diffraction, and adsorption of gases. He pioneered the theory of fibre diffraction analysis in 1921, and the dislocation theory of plastic deformation of ductile metals and other materials in 1934. He immigrated to Germany, in 1926 becoming a chemistry professor at the Kaiser Wilhelm Institute in Berlin, and then in 1933 to England, becoming first a chemistry professor, and then a social sciences professor at the University of Manchester. Two of his pupils, and his son John Charles Polanyi won Nobel Prizes in Chemistry. In 1944 Polanyi was elected to the Royal Society. The contribution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marcos Moshinsky
Marcos Moshinsky Borodiansky (russian: Маркос Мошинский Бородянский; uk, Маркос Мошинскі; 1921–2009) was a Mexican physicist of Ukrainian-Jewish origin whose work in the field of elementary particles won him the Prince of Asturias Prize for Scientific and Technical Investigation in 1988 and the UNESCO Science Prize in 1997. Early life He was born in 1921 into a Jewish family in Kyiv, Ukrainian SSR. At the age of three, he emigrated as a refugee to Mexico, where he became a naturalized citizen in 1942. He received a bachelor's degree in physics from the National Autonomous University of Mexico (UNAM) and a doctorate in the same discipline at Princeton University under Nobel Laureate Eugene Paul Wigner. Career In the 1950s he researched nuclear reactions and the structure of the atomic nucleus, introducing the concept of the '' transformation bracket for eigenstates of the quantum harmonic oscillator'', which, together with the tables ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manhattan Project
The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the U.S. Army Corps of Engineers. Nuclear physicist Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the actual bombs. The Army component of the project was designated the Manhattan District as its first headquarters were in Manhattan; the placename gradually superseded the official codename, Development of Substitute Materials, for the entire project. Along the way, the project absorbed its earlier British counterpart, Tube Alloys. The Manhattan Project began modestly in 1939, but grew to employ more than 130,000 people and cost nearly US$2 billion (equivalent to about $ billion in ). Over 90 percent of the cost was for building factories an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conyers Herring
William Conyers Herring (November 15, 1914 – July 23, 2009) was an American physicist. He was a Professor of Applied Physics at Stanford University and the Wolf Prize in Physics recipient in 1984/5. Academic career Conyers Herring completed his Ph.D. in physics from Princeton University in 1937, submitting a dissertation entitled ''On Energy Coincidences in the Theory of Brillouin Zones'' under the direction of Eugene Wigner. In 1946, he joined the technical staff of Bell Laboratories in Murray Hill, New Jersey, where he remained until 1978. Then, he joined the faculty at Stanford University. Contributions Conyers Herring played a major role in the development of solid state physics. He laid the foundations of band structure calculations of metals and semiconductors, culminating in the discovery of the Orthogonalized Plane Wave Method (O.P.W.) in 1940. He was years ahead of his time in this contribution. A great deal of modern solid state physics as produced today stems from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
