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. 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
Quantum gravity Quantum gravity (QG) is a field of theoretical physics that seeks to describe the force of gravity according to the principles of quantum mechanics. Although a quantum theory of gravity is needed in order to reconcile general relativity with the principles of quantum mechanics, difficulties arise when one attempts to apply the usual prescriptions of quantum field theory to the force of gravity. From a technical point of view, the problem is that the theory one gets in this way is not renormalizable and therefore cannot be used to make meaningful physical predictions. As a result, theorists have taken up more radical approaches to the problem of quantum gravity, the most popular approaches being string theory and loop quantum gravity. Strictly speaking, the aim of quantum gravity is only to describe the quantum behavior of the gravitational field and should not be confused with the objective of unifying all fundamental interactions into a single mathematical framework.
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.
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).
Strange matter Strange matter is a particular form of quark matter, usually thought of as a "liquid" of up, down, and strange quarks. It is to be contrasted with nuclear matter, which is a liquid of neutrons and protons (which themselves are built out of up and down quarks), and with non-strange quark matter, which is a quark liquid containing only up and down quarks. At high enough density, strange matter is expected to be color superconducting. Two meanings of the term "strange matter" In particle physics and astrophysics, the term is used in two ways, one broader and the other more specific  The broader meaning is just quark matter that contains three flavors of quarks: up, down, and strange. Strange matter that is only stable at high pressure Under the broader definition, strange matter might occur inside neutron stars, if the pressure at their core is high enough (i.e. above the critical pressure). A neutron star with a quark matter core is often  called a hybrid star.
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
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.
Color confinement The color force favors confinement because at a certain range it is more energetically favorable to create a quark-antiquark pair than to continue to elongate the color flux tube. This is analoguous to the behavior of an elongated rubber-band. An animation of color confinement. Energy is supplied to the quarks, and the gluon tube elongates until it reaches a point where it "snaps" and forms a quark-antiquark pair. Color confinement, often simply called confinement, is the phenomenon that color charged particles (such as quarks) cannot be isolated singularly, and therefore cannot be directly observed. Quarks, by default, clump together to form groups, or hadrons. The two types of hadrons are the mesons (one quark, one antiquark) and the baryons (three quarks). Origin The reasons for quark confinement are somewhat complicated; no analytic proof exists that quantum chromodynamics should be confining. Models exhibiting confinement Models of fully screened quarks Quarks
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. 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'). 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.
Round-electron challenge to mainstream physics | Crisis-in-Physics At last the cautious BBC voices physicists’ majority view that Gravity is not explained by the “Standard Model” of physics (Pallab Ghosh 25 May 2011) – meaning ‘gravitons’ are unreal – in an offhand comment on the electron-is-round story. Modern physics is trying to get to grips with a finite size electron. The egg-shape predicted by the supersymmetry model is close to being excluded by the latest experiments (Jony Hudson et al. at Imperial College). The Kapitsa-Dirac model is also up for question. Will this help challenge unified field theory by exposing the myth of the photon, returning to ‘photons are waves, but electrons are particles’ ? Like this: Like Loading... This entry was posted in Uncategorized and tagged duality, electromagnetic fields, electron shape, graviton, Jony Hudson, Kapitsa-Dirac, quantum mechanics, round electron, Standard Model, Trevor Marshall.
Elementary particle In particle physics, an elementary particle or fundamental particle is a particle whose substructure is unknown, thus it is unknown whether it is composed of other particles. Known elementary particles include the fundamental fermions (quarks, leptons, antiquarks, and antileptons), which generally are "matter particles" and "antimatter particles", as well as the fundamental bosons (gauge bosons and Higgs boson), which generally are "force particles" that mediate interactions among fermions. A particle containing two or more elementary particles is a composite particle. Everyday matter is composed of atoms, once presumed to be matter's elementary particles—atom meaning "indivisible" in Greek—although the atom's existence remained controversial until about 1910, as some leading physicists regarded molecules as mathematical illusions, and matter as ultimately composed of energy. Soon, subatomic constituents of the atom were identified. Overview Main article: Standard Model