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C.N. Yang
Yang Chen-Ning or Chen-Ning Yang (; born 1 October 1922), also known as C. N. Yang or by the English name Frank Yang, is a Chinese theoretical physicist who made significant contributions to statistical mechanics, integrable systems, gauge theory, and both particle physics and condensed matter physics. He and Tsung-Dao Lee received the 1957 Nobel Prize in Physics for their work on parity non-conservation of weak interaction. The two proposed that one of the basic quantum-mechanics laws, the conservation of parity, is violated in the so-called weak nuclear reactions, those nuclear processes that result in the emission of beta or alpha particles. Yang is also well known for his collaboration with Robert Mills in developing non-abelian gauge theory, widely known as the Yang–Mills theory. Biography Yang was born in Hefei, Anhui, China; his father, (; 1896–1973), was a mathematician, and his mother, Meng Hwa Loh Yang (), was a housewife. Yang attended elementary school ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yang (surname)
Yang (; ) is the transcription of a Chinese family name. It is the sixth most common surname in Mainland China. It is the 16th surname on the ''Hundred Family Surnames'' text. The Yang clan was founded by Boqiao, son of Duke Wu of Jin in the Spring and Autumn Period of the Ji (姬) surname, the surname of the royal family during the Zhou dynasty ) who was enfeoffed in the state of Yang. History The German sociologist Wolfram Eberhard calls Yang the "Monkey Clan", citing the totemistic myth recorded in the ''Soushenji'' and ''Fayuan Zhulin'' that the Yangs living in southwestern Shu (modern Sichuan) were descendants of monkeys. The ''Soushenji'' "reported that in the southwest of Shu there were monkey-like animals whose names were ''jiaguo'' (猳國), ''mahua'' (馬化), or '' jueyuan'' (玃猿). These animals abducted women and sent them back when they became pregnant. If the baby were not accepted, the woman would have to die. Therefore these children were raised and they re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gauge Theory
In physics, a gauge theory is a type of field theory in which the Lagrangian (and hence the dynamics of the system itself) does not change (is invariant) under local transformations according to certain smooth families of operations (Lie groups). The term ''gauge'' refers to any specific mathematical formalism to regulate redundant degrees of freedom in the Lagrangian of a physical system. The transformations between possible gauges, called ''gauge transformations'', form a Lie group—referred to as the ''symmetry group'' or the ''gauge group'' of the theory. Associated with any Lie group is the Lie algebra of group generators. For each group generator there necessarily arises a corresponding field (usually a vector field) called the ''gauge field''. Gauge fields are included in the Lagrangian to ensure its invariance under the local group transformations (called ''gauge invariance''). When such a theory is quantized, the quanta of the gauge fields are called '' gauge bosons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G-parity
In particle physics, G-parity is a multiplicative quantum number that results from the generalization of C-parity to multiplets of particles. ''C''-parity applies only to neutral systems; in the pion triplet, only π0 has ''C''-parity. On the other hand, strong interaction does not see electrical charge, so it cannot distinguish amongst π+, π0 and π−. We can generalize the ''C''-parity so it applies to all charge states of a given multiplet: :\mathcal G \begin \pi^+ \\ \pi^0 \\ \pi^- \end = \eta_G \begin \pi^+ \\ \pi^0 \\ \pi^- \end where ''ηG'' = ±1 are the eigenvalues of ''G''-parity. The ''G''-parity operator is defined as :\mathcal G = \mathcal C \, e^ where \mathcal C is the ''C''-parity operator, and ''I''2 is the operator associated with the 2nd component of the isospin "vector". ''G''-parity is a combination of charge conjugation and a Pi, π radian, rad (180°) rotation around the 2nd axis of isospin space. Given that charge conjugation and isospin are p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CP Violation
In particle physics, CP violation is a violation of CP-symmetry (or charge conjugation parity symmetry): the combination of C-symmetry (charge symmetry) and P-symmetry ( parity symmetry). CP-symmetry states that the laws of physics should be the same if a particle is interchanged with its antiparticle (C-symmetry) while its spatial coordinates are inverted ("mirror" or P-symmetry). The discovery of CP violation in 1964 in the decays of neutral kaons resulted in the Nobel Prize in Physics in 1980 for its discoverers James Cronin and Val Fitch. It plays an important role both in the attempts of cosmology to explain the dominance of matter over antimatter in the present universe, and in the study of weak interactions in particle physics. Overview Until the 1950s, parity conservation was believed to be one of the fundamental geometric conservation laws (along with conservation of energy and conservation of momentum). After the discovery of parity violation in 1956, CP-symmetry was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wu–Yang Monopole
The Wu–Yang monopole was the first solution (found in 1968 by Tai Tsun Wu and Chen Ning YangWu, T.T. and Yang, C.N. (1968) in ''Properties of Matter Under Unusual Conditions'', edited by H. Mark and S. Fernbach (Interscience, New York)) to the Yang–Mills field equations. It describes a magnetic monopole which is pointlike and has a potential which behaves like 1/''r'' everywhere. See also * Meron *Dyon *Instanton An instanton (or pseudoparticle) is a notion appearing in theoretical and mathematical physics. An instanton is a classical solution to equations of motion with a finite, non-zero action, either in quantum mechanics or in quantum field theory. Mo ... * Monopole Notes References * ''Gauge Fields, Classification and Equations of Motion'', M.Carmeli, Kh. Huleilil and E. Leibowitz, World Scientific Publishing * Gauge theories Magnetic monopoles {{quantum-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Off-diagonal Long-range Order
In geometry, a diagonal is a line segment joining two vertices of a polygon or polyhedron, when those vertices are not on the same edge. Informally, any sloping line is called diagonal. The word ''diagonal'' derives from the ancient Greek διαγώνιος ''diagonios'', "from angle to angle" (from διά- ''dia-'', "through", "across" and γωνία ''gonia'', "angle", related to ''gony'' "knee"); it was used by both Strabo and Euclid to refer to a line connecting two vertices of a rhombus or cuboid, and later adopted into Latin as ''diagonus'' ("slanting line"). In matrix algebra, the diagonal of a square matrix consists of the entries on the line from the top left corner to the bottom right corner. There are also other, non-mathematical uses. Non-mathematical uses In engineering, a diagonal brace is a beam used to brace a rectangular structure (such as scaffolding) to withstand strong forces pushing into it; although called a diagonal, due to practical considerations d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landau–Yang Theorem
In quantum mechanics, the Landau–Yang theorem is a selection rule for particles that decay into two on-shell photons. The theorem states that a massive particle with spin 1 cannot decay into two photons. Assumptions A photon here is any particle with spin 1, without mass and without internal degrees of freedom. The photon is the only known particle with these properties. Consequences The theorem has several consequences in particle physics. For example: * The meson ρ cannot decay into two photons, differently from the neutral pion, that almost always decays into this final state (98.8% of times). * The boson Z cannot decay into two photons. * The Higgs boson The Higgs boson, sometimes called the Higgs particle, is an elementary particle in the Standard Model of particle physics produced by the quantum excitation of the Higgs field, one of the fields in particle physics theory. In the Stand ..., whose spin was not measured before 2013, but whose decay into t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yang–Baxter Equation
In physics, the Yang–Baxter equation (or star–triangle relation) is a consistency equation which was first introduced in the field of statistical mechanics. It depends on the idea that in some scattering situations, particles may preserve their momentum while changing their quantum internal states. It states that a matrix R, acting on two out of three objects, satisfies :(\check\otimes \mathbf)(\mathbf\otimes \check)(\check\otimes \mathbf) =(\mathbf\otimes \check)(\check \otimes \mathbf)(\mathbf\otimes \check) In one dimensional quantum systems, R is the scattering matrix and if it satisfies the Yang–Baxter equation then the system is integrable. The Yang–Baxter equation also shows up when discussing knot theory and the braid groups where R corresponds to swapping two strands. Since one can swap three strands two different ways, the Yang–Baxter equation enforces that both paths are the same. It takes its name from independent work of C. N. Yang from 1968, and R. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
