# Graviton

Theory The three other known forces of nature are mediated by elementary particles: electromagnetism by the photon, the strong interaction by the gluons, and the weak interaction by the W and Z bosons. The hypothesis is that the gravitational interaction is likewise mediated by an – as yet undiscovered – elementary particle, dubbed as the graviton. In the classical limit, the theory would reduce to general relativity and conform to Newton's law of gravitation in the weak-field limit.[6][7][8] Gravitons and renormalization When describing graviton interactions, the classical theory (i.e., the tree diagrams) and semiclassical corrections (one-loop diagrams) behave normally, but Feynman diagrams with two (or more) loops lead to ultraviolet divergences; that is, infinite results that cannot be removed because the quantized general relativity is not renormalizable, unlike quantum electrodynamics. Comparison with other forces Gravitons in speculative theories See also Related:  Leselistemindsspécial à revoir

Graviton Theory The three other known forces of nature are mediated by elementary particles: electromagnetism by the photon, the strong interaction by the gluons, and the weak interaction by the W and Z bosons. The hypothesis is that the gravitational interaction is likewise mediated by an – as yet undiscovered – elementary particle, dubbed as the graviton. In the classical limit, the theory would reduce to general relativity and conform to Newton's law of gravitation in the weak-field limit.[6][7][8] Gravitons and renormalization When describing graviton interactions, the classical theory (i.e., the tree diagrams) and semiclassical corrections (one-loop diagrams) behave normally, but Feynman diagrams with two (or more) loops lead to ultraviolet divergences; that is, infinite results that cannot be removed because the quantized general relativity is not renormalizable, unlike quantum electrodynamics. Comparison with other forces Gravitons in speculative theories See also

Higgs boson The Higgs boson is named after Peter Higgs, one of six physicists who, in 1964, proposed the mechanism that suggested the existence of such a particle. Although Higgs's name has come to be associated with this theory, several researchers between about 1960 and 1972 each independently developed different parts of it. In mainstream media the Higgs boson has often been called the "God particle", from a 1993 book on the topic; the nickname is strongly disliked by many physicists, including Higgs, who regard it as inappropriate sensationalism.[17][18] In 2013 two of the original researchers, Peter Higgs and François Englert, were awarded the Nobel Prize in Physics for their work and prediction[19] (Englert's co-researcher Robert Brout had died in 2011). A non-technical summary "Higgs" terminology Overview If this field did exist, this would be a monumental discovery for science and human knowledge, and is expected to open doorways to new knowledge in many fields. History

Tests of general relativity The very strong gravitational fields that must be present close to black holes, especially those supermassive black holes which are thought to power active galactic nuclei and the more active quasars, belong to a field of intense active research. Observations of these quasars and active galactic nuclei are difficult, and interpretation of the observations is heavily dependent upon astrophysical models other than general relativity or competing fundamental theories of gravitation, but they are qualitatively consistent with the black hole concept as modelled in general relativity. As a consequence of the equivalence principle, Lorentz invariance holds locally in freely falling reference frames. Experiments related to Lorentz invariance and thus special relativity (i.e., when gravitational effects can be neglected) are described in Tests of special relativity. Classical tests The chief attraction of the theory lies in its logical completeness. Perihelion precession of Mercury

Graham's number Graham's number, named after Ronald Graham, is a large number that is an upper bound on the solution to a problem in Ramsey theory. The number gained a degree of popular attention when Martin Gardner described it in the "Mathematical Games" section of Scientific American in November 1977, writing that, "In an unpublished proof, Graham has recently established ... a bound so vast that it holds the record for the largest number ever used in a serious mathematical proof." The 1980 Guinness Book of World Records repeated Gardner's claim, adding to the popular interest in this number. According to physicist John Baez, Graham invented the quantity now known as Graham's number in conversation with Gardner himself. Graham's number is unimaginably larger than other well-known large numbers such as a googol, googolplex, and even larger than Skewes' number and Moser's number. Context Example of a 2-colored 3-dimensional cube containing one single-coloured 4-vertex coplanar complete subgraph.

Quark A quark (/ˈkwɔrk/ or /ˈkwɑrk/) is an elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei.[1] Due to a phenomenon known as color confinement, quarks are never directly observed or found in isolation; they can be found only within hadrons, such as baryons (of which protons and neutrons are examples), and mesons.[2][3] For this reason, much of what is known about quarks has been drawn from observations of the hadrons themselves. The quark model was independently proposed by physicists Murray Gell-Mann and George Zweig in 1964.[5] Quarks were introduced as parts of an ordering scheme for hadrons, and there was little evidence for their physical existence until deep inelastic scattering experiments at the Stanford Linear Accelerator Center in 1968.[6][7] Accelerator experiments have provided evidence for all six flavors. Classification

Membrane (M-theory) In string theory and related theories, D-branes are an important class of branes that arise when one considers open strings. As an open string propagates through spacetime, its endpoints are required to lie on a D-brane. The letter "D" in D-brane refers to the fact that we impose a certain mathematical condition on the system known as the Dirichlet boundary condition. The study of D-branes has led to important results, such as the anti-de Sitter/conformal field theory correspondence, which has shed light on many problems in quantum field theory. See also References Jump up ^ Moore, Gregory (2005).

Gluon Gluons /ˈɡluːɒnz/ are elementary particles that act as the exchange particles (or gauge bosons) for the strong force between quarks, analogous to the exchange of photons in the electromagnetic force between two charged particles.[6] In technical terms, gluons are vector gauge bosons that mediate strong interactions of quarks in quantum chromodynamics (QCD). Gluons themselves carry the color charge of the strong interaction. This is unlike the photon, which mediates the electromagnetic interaction but lacks an electric charge. Gluons therefore participate in the strong interaction in addition to mediating it, making QCD significantly harder to analyze than QED (quantum electrodynamics). Properties Diagram 1: e+e− -> Y(9.46) -> 3g Numerology of gluons Unlike the single photon of QED or the three W and Z bosons of the weak interaction, there are eight independent types of gluon in QCD. This may be difficult to understand intuitively. Color charge and superposition A.

Fundamental interaction Fundamental interactions, also called fundamental forces or interactive forces, are modeled in fundamental physics as patterns of relations in physical systems, evolving over time, that appear not reducible to relations among entities more basic. Four fundamental interactions are conventionally recognized: gravitational, electromagnetic, strong nuclear, and weak nuclear. Everyday phenomena of human experience are mediated via gravitation and electromagnetism. The strong interaction, synthesizing chemical elements via nuclear fusion within stars, holds together the atom's nucleus, and is released during an atomic bomb's detonation. The weak interaction is involved in radioactive decay. (Speculations of a fifth force—perhaps an added gravitational effect—remain widely disputed.) In modern physics, gravitation is the only fundamental interaction still modeled as classical/continuous (versus quantum/discrete). Overview of the fundamental Interaction The interactions

Interconnectedness Interconnectedness is part of the terminology of a worldview which sees a oneness in all things. A similar term, interdependence, is sometimes used instead, although there are slightly different connotations. Both terms tend to refer to the idea that all things are of a single underlying substance and reality, and that there is no true separation deeper than appearances. Some feel that 'interconnectedness' and similar terms are part of a contemporary lexicon of mysticism, which is based on the same core idea of universal oneness. Economic The economic interconnectedness, so called economic globalization, has evolved and developed ever since the time immemorial with the countries bartering in prospect of finding mutual interests and gains. There are number of categories on economic interconnectedness. "Globalization means international interdependence with disadvantages as well as advantages. Religion The mystics[who?] Politics Implications See also

Neutron The neutron is a subatomic hadron particle that has the symbol n or n0. Neutrons have no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen-1, the nucleus of every atom consists of at least one or more of both protons and neutrons. Protons and neutrons are collectively referred to as "nucleons". While the bound neutrons in nuclei can be stable (depending on the nuclide), free neutrons are unstable; they undergo beta decay with a mean lifetime of just under 15 minutes (881.5±1.5 s).[5] Free neutrons are produced in nuclear fission and fusion. The neutron has been key to the production of nuclear power. Discovery In 1920, Ernest Rutherford conceived the possible existence of the neutron.[2][7] In particular, Rutherford considered that the disparity found between the atomic number of an atom and its atomic mass could be explained by the existence of a neutrally charged particle within the atomic nucleus. Intrinsic properties

The Joy of Gravitons, Hyperspace, Branes and Brainstorms In addition to the incredulity of their colleagues, Dr. Lisa Randall of Princeton University and Dr. Raman Sundrum of Stanford University faced a big theoretical challenge in making their theory of space-time work. They were proposing that this universe is just one of many three-dimensional bubbles (called branes) floating inside a four-dimensional hyperspace. According to string theory, most particles are made from strings that are open-ended, like scraps of thread. This would create all kinds of problems. But gravity in a four-dimensional universe would obey an inverse cube law. Here was the theorists' answer: according to Einstein's general theory of relativity, gravity is simply warped space-time -- bends in the brane on which this universe resides. ''Gravity would be sucked back toward the brane by the brane's own gravitational force,'' Dr. Taking the idea further, Dr. ''By contrast, our brane would be a lonely backwater where gravity's effects are very diluted,'' Dr.

List of particles This is a list of the different types of particles found or believed to exist in the whole of the universe. For individual lists of the different particles, see the individual pages given below. Elementary particles Fermions Fermions are one of the two fundamental classes of particles, the other being bosons. Fermions have half-integer spin; for all known elementary fermions this is 1⁄2. Quarks Leptons Bosons Bosons are one of the two fundamental classes of particles, the other being fermions. The fundamental forces of nature are mediated by gauge bosons, and mass is believed to be created by the Higgs Field. The graviton is added to the list[citation needed] although it is not predicted by the Standard Model, but by other theories in the framework of quantum field theory. Hypothetical particles Supersymmetric theories predict the existence of more particles, none of which have been confirmed experimentally as of 2014: Composite particles Hadrons

Gravity Probe B - Special & General Relativity Questions and Answers It is true that, given enough energy, you could be propelled so fast that 1 year back home would pass for you in a few minutes; a ride across the Milky Way covering 100,000 light years could be done in a few seconds; or even a ride across the visible universe of 14 billion light years could be done in a second or less...given an ultimate source of power to get you to those speeds. For a photon, or any other particle traveling at ESSENTIALLY the speed of light, any arbitrarily long distance could be traversed in less than a second....but eternity is different. For you to get boosted to a speed where 'eternity would pass in an instant' you would travel essentially an infinite distance, and the energy you would need to accelerate you would be infinite as well. Return to the Special & General Relativity Questions and Answers page. All answers are provided by Dr.

Polysemy Charles Fillmore and Beryl Atkins’ definition stipulates three elements: (i) the various senses of a polysemous word have a central origin, (ii) the links between these senses form a network, and (iii) understanding the ‘inner’ one contributes to understanding of the ‘outer’ one.[3] Polysemy is a pivotal concept within disciplines such as media studies and linguistics. Polysemes A polyseme is a word or phrase with different, but related senses. In vertical polysemy a word refers to a member of a subcategory (e.g., 'dog' for 'male dog').[4] A closely related idea is metonym, in which a word with one original meaning is used to refer to something else connected to it. There are several tests for polysemy, but one of them is zeugma: if one word seems to exhibit zeugma when applied in different contexts, it is likely that the contexts bring out different polysemes of the same word. Examples Man Mole Bank However: a river bank is a homonym to 1 and 2, as they do not share etymologies.

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