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Dual Resonance Model
In theoretical physics, a dual resonance model arose during the early investigation (1968–1973) of string theory as an S-matrix theory of the strong interaction. Overview The dual resonance model was based upon the observation that the amplitudes for the s-channel scatterings matched exactly with the amplitudes for the t-channel scatterings among mesons and also the Regge trajectory. It began with the Euler beta function model of Gabriele Veneziano in 1968 for a 4-particle amplitude which has the property that it is explicitly s–t crossing symmetric, exhibits duality between the description in terms of Regge poles or of resonances, and provides a closed-form solution to non-linear finite-energy sum rules relating s- and t- channels. The Veneziano formula was quickly generalized to an equally consistent ''N''-particle amplitude for which Yoichiro Nambu, Holger Bech Nielsen, and Leonard Susskind provided a physical interpretation in terms of an infinite number of simple harm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theoretical Physics
Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. This is in contrast to experimental physics, which uses experimental tools to probe these phenomena. The advancement of science generally depends on the interplay between experimental studies and theory. In some cases, theoretical physics adheres to standards of mathematical rigour while giving little weight to experiments and observations.There is some debate as to whether or not theoretical physics uses mathematics to build intuition and illustrativeness to extract physical insight (especially when normal experience fails), rather than as a tool in formalizing theories. This links to the question of it using mathematics in a less formally rigorous, and more intuitive or heuristic way than, say, mathematical physics. For example, while developing special relativity, Albert Einstein was concerned wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holger Bech Nielsen
Holger Bech Nielsen (born 25 August 1941) is a Danish theoretical physicist and professor emeritus at the Niels Bohr Institute, at the University of Copenhagen, where he started studying physics in 1961. Work Nielsen has made original contributions to theoretical particle physics, specifically in the field of string theory. Independently of Nambu and Susskind, he was the first to propose that the Veneziano model was actually a theory of strings, leading him to be considered among the fathers of string theory. He was awarded the Humboldt Prize in 2001 for his research. Several physics concepts are named after him, e.g. Nielsen–Olesen vortex and the Nielsen-Ninomiya no-go theorem for representing chiral fermions on the lattice. In the original Dual-Models, which later would be recognized as the origins of string theory, the Koba-Nielsen variables are also named after him and his collaborator Ziro Koba. Nielsen is known in Denmark for his enthusiastic public lectures on physic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lund String Model
In particle physics, the Lund string model is a phenomenological model of hadronization. It treats all but the highest-energy gluons as field lines, which are attracted to each other due to the gluon self-interaction and so form a narrow tube (or string) of strong color field. Compared to electric or magnetic field lines, which are spread out because the carrier of the electromagnetic force, the photon, does not interact with itself. String fragmentation is one of the parton fragmentation models used in the PYTHIA/Jetset and UCLA event generators, and explains many features of hadronization quite well. In particular, the model predicts that in addition to the particle jets formed along the original paths of two separating quarks, there will be a spray of hadrons produced between the jets by the string itself—which is precisely what is observed. This use of "string" is not the same as in string theory, in which strings are the fundamental objects of nature rather tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QCD String
In theoretical physics, quantum chromodynamics (QCD) is the theory of the strong interaction between quarks mediated by gluons. Quarks are fundamental particles that make up composite hadrons such as the proton, neutron and pion. QCD is a type of quantum field theory called a non-abelian gauge theory, with symmetry group SU(3). The QCD analog of electric charge is a property called ''color''. Gluons are the force carriers of the theory, just as photons are for the electromagnetic force in quantum electrodynamics. The theory is an important part of the Standard Model of particle physics. A large body of experimental evidence for QCD has been gathered over the years. QCD exhibits three salient properties: * Color confinement. Due to the force between two color charges remaining constant as they are separated, the energy grows until a quark–antiquark pair is spontaneously produced, turning the initial hadron into a pair of hadrons instead of isolating a color charge. Although an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymptotic Freedom
In quantum field theory, asymptotic freedom is a property of some gauge theories that causes interactions between particles to become asymptotically weaker as the energy scale increases and the corresponding length scale decreases. Asymptotic freedom is a feature of quantum chromodynamics (QCD), the quantum field theory of the strong interaction between quarks and gluons, the fundamental constituents of nuclear matter. Quarks interact weakly at high energies, allowing perturbative calculations. At low energies, the interaction becomes strong, leading to the confinement of quarks and gluons within composite hadrons. The asymptotic freedom of QCD was discovered in 1973 by David Gross and Frank Wilczek, and independently by David Politzer in the same year. For this work all three shared the 2004 Nobel Prize in Physics. Discovery Asymptotic freedom in QCD was discovered in 1973 by David Gross and Frank Wilczek, and independently by David Politzer in the same year. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Chromodynamics
In theoretical physics, quantum chromodynamics (QCD) is the theory of the strong interaction between quarks mediated by gluons. Quarks are fundamental particles that make up composite hadrons such as the proton, neutron and pion. QCD is a type of quantum field theory called a non-abelian gauge theory, with symmetry group SU(3). The QCD analog of electric charge is a property called ''color''. Gluons are the force carriers of the theory, just as photons are for the electromagnetic force in quantum electrodynamics. The theory is an important part of the Standard Model of particle physics. A large body of experimental evidence for QCD has been gathered over the years. QCD exhibits three salient properties: * Color confinement. Due to the force between two color charges remaining constant as they are separated, the energy grows until a quark–antiquark pair is spontaneously produced, turning the initial hadron into a pair of hadrons instead of isolating a color charge. Although ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sergio Fubini
Sergio Fubini (December 31, 1928 – January 6, 2005) was an Italians, Italian theoretical physicist. He was one of the pioneers of string theory. He was engaged in peace activism in the Middle East. Biography Fubini was born in Turin. In 1938, he fled the country as a politically persecuted Jew to Switzerland. In 1945, he attended the Lycée in Turin, where he studied physics and in 1950 graduated "cum laude." Afterwards, he was an assistant in Turin. From 1954 to 1957, he was in the USA. From 1958 to 1967, he was at CERN in Geneva. In 1959, he became a professor for nuclear physics at University of Padua. In 1961, he became a professor for theoretical physics at University of Turin. From 1968 to 1973, he was at Massachusetts Institute of Technology, MIT, but taught summer courses in Turin. He went back to CERN in 1973 and was from 1971 to 1980 a member of the advisory board and had an important role in planning the Large Electron Positron Collider (LEP) as well as in discussion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
String Theory
In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. String theory describes how these strings propagate through space and interact with each other. On distance scales larger than the string scale, a string looks just like an ordinary particle, with its mass, charge, and other properties determined by the vibrational state of the string. In string theory, one of the many vibrational states of the string corresponds to the graviton, a quantum mechanical particle that carries the gravitational force. Thus, string theory is a theory of quantum gravity. String theory is a broad and varied subject that attempts to address a number of deep questions of fundamental physics. String theory has contributed a number of advances to mathematical physics, which have been applied to a variety of problems in black hole physics, early universe cosmology, nuclear physics, and conde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Harmonic Oscillator
In mechanics and physics, simple harmonic motion (sometimes abbreviated ) is a special type of periodic motion of a body resulting from a dynamic equilibrium between an inertial force, proportional to the acceleration of the body away from the static equilibrium position and a restoring force on the moving object that is directly proportional to the magnitude of the object's displacement and acts towards the object's equilibrium position. It results in an oscillation, described by a sinusoid which continues indefinitely, if uninhibited by friction or any other dissipation of energy. Simple harmonic motion can serve as a mathematical model for a variety of motions, but is typified by the oscillation of a mass on a spring when it is subject to the linear elastic restoring force given by Hooke's law. The motion is sinusoidal in time and demonstrates a single resonant frequency. Other phenomena can be modeled by simple harmonic motion, including the motion of a simple pendulum, al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonard Susskind
Leonard Susskind (; born June 16, 1940)his 60th birthday was celebrated with a special symposium at Stanford University.in Geoffrey West's introduction, he gives Suskind's current age as 74 and says his birthday was recent. is an American physicist, who is a professor of theoretical physics at Stanford University, and founding director of the Stanford Institute for Theoretical Physics. His research interests include string theory, quantum field theory, quantum statistical mechanics and quantum cosmology. He is a member of the US National Academy of Sciences, and the American Academy of Arts and Sciences, an associate member of the faculty of Canada's Perimeter Institute for Theoretical Physics, and a distinguished professor of the Korea Institute for Advanced Study. Susskind is widely regarded as one of the fathers of string theory. He was the first to give a precise string-theoretic interpretation of the holographic principle in 1995 and the first to introduce the idea of the stri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nordita
The Nordic Institute for Theoretical Physics, or NORDITA, or Nordita ( da, Nordisk Institut for Teoretisk Fysik), is an international organisation for research in theoretical physics. It was established as Nordisk Institut for Teoretisk Atomfysik in 1957 by Niels Bohr and the Swedish physicist Torsten Gustafson. Nordita was originally located at the Niels Bohr Institute in Copenhagen (Denmark), but moved to the AlbaNova University Centre in Stockholm ( Sweden) on 1 January 2007. The main research areas at Nordita are astrophysics, hard and soft condensed matter physics, and high-energy physics. Research Since Nordita's establishment in 1957 the original focus on research in atomic and nuclear physics has been broadened. Research carried out by Nordita's academic staff presently includes astrophysics, biological physics, hard condensed matter physics and materials physics, soft condensed matter physics, cosmology, statistical physics and complex systems, high-energ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yoichiro Nambu
was a Japanese-American physicist and professor at the University of Chicago. Known for his contributions to the field of theoretical physics, he was awarded half of the Nobel Prize in Physics in 2008 for the discovery in 1960 of the mechanism of spontaneous broken symmetry in subatomic physics, related at first to the strong interaction's chiral symmetry and later to the electroweak interaction and Higgs mechanism. The other half was split equally between Makoto Kobayashi and Toshihide Maskawa "for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature." Early life and education Nambu was born in Tokyo, Japan, in 1921. After graduating from the then Fukui Secondary High School in Fukui City, he enrolled in the Imperial University of Tokyo and studied physics. He received his Bachelor of Science in 1942 and Doctorate of Science in 1952. In 1949 he was appointed to associate professor at Osaka City Unive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
