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Type I String
In theoretical physics, type I string theory is one of five consistent supersymmetric string theory, string theories in ten dimensions. It is the only one whose strings are unoriented (both orientations of a string are equivalent) and the only one which perturbatively contains not only closed strings, but also Open string (physics), open strings. The terminology of type I and type II string theory, type II was coined by John Henry Schwarz in 1982 to classify the three string theories known at the time. Overview The classic 1976 work of Ferdinando Gliozzi, Joël Scherk and David Olive paved the way to a systematic understanding of the rules behind string spectra in cases where only closed strings are present via modular invariance. It did not lead to similar progress for models with open strings, despite the fact that the original discussion was based on the type I string theory. As first proposed by Augusto Sagnotti in 1988, the type I string theory can be obtained as an orientifo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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 List of natural phenomena, 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 E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Anomaly (physics)
In quantum physics an anomaly or quantum anomaly is the failure of a symmetry of a theory's classical action to be a symmetry of any regularization of the full quantum theory. In classical physics, a classical anomaly is the failure of a symmetry to be restored in the limit in which the symmetry-breaking parameter goes to zero. Perhaps the first known anomaly was the dissipative anomaly in turbulence: time-reversibility remains broken (and energy dissipation rate finite) at the limit of vanishing viscosity Viscosity is a measure of a fluid's rate-dependent drag (physics), resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for e .... In quantum theory, the first anomaly discovered was the Adler–Bell–Jackiw anomaly, wherein the Chiral_anomaly, axial vector current is conserved as a classical symmetry of electrodynamics, but is broken by the quantized ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Heterotic String
In string theory, a heterotic string is a closed string (or loop) which is a hybrid ('heterotic') of a superstring and a bosonic string. There are two kinds of heterotic superstring theories, the heterotic SO(32) and the heterotic E8 × E8, abbreviated to HO and HE. Apart from that there exist seven more heterotic string theories which are not supersymmetric and hence are only of secondary importance in most applications. Heterotic string theory was first developed in 1985 by David Gross, Jeffrey Harvey, Emil Martinec, and Ryan Rohm (the so-called "Princeton string quartet"), in one of the key papers that fueled the first superstring revolution. Overview In string theory, the left-moving and the right-moving excitations of strings are completely decoupled for a closed string, and it is possible to construct a string theory whose left-moving (counter-clockwise) excitations are treated as a bosonic string propagating in ''D'' = 26 dimensions, while the righ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Edward Witten
Edward Witten (born August 26, 1951) is an American theoretical physics, theoretical physicist known for his contributions to string theory, topological quantum field theory, and various areas of mathematics. He is a professor emeritus in the school of natural sciences at the Institute for Advanced Study in Princeton, New Jersey, Princeton. Witten is a researcher in string theory, quantum gravity, supersymmetry, supersymmetric quantum field theories, and other areas of mathematical physics. Witten's work has also significantly impacted pure mathematics. In 1990, he became the first physicist to be awarded a Fields Medal by the International Mathematical Union, for his mathematical insights in physics, such as his 1981 proof of the positive energy theorem in general relativity, and his interpretation of the Vaughan Jones, Jones invariants of knots as Feynman integrals. He is considered the practical founder of M-theory.Duff 1998, p. 65 Early life and education Witten was born on A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
D-brane
In string theory, D-branes, short for Dirichlet membrane, are a class of extended objects upon which open strings can end with Dirichlet boundary conditions, after which they are named. D-branes are typically classified by their spatial dimension, which is indicated by a number written after the ''D.'' A D0-brane is a single point, a D1-brane is a line (sometimes called a "D-string"), a D2-brane is a plane, and a D25-brane fills the highest-dimensional space considered in bosonic string theory. There are also instantonic D(−1)-branes, which are localized in both space and time. Discovery D-branes were discovered by Jin Dai, Robert Leigh, and Joseph Polchinski, and independently by Petr Hořava, in 1989. In 1995, Polchinski identified D-branes with black p-brane solutions of supergravity, a discovery that triggered the second superstring revolution and led to both holographic and M-theory dualities. Theoretical background The equations of motion of string theory r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Joseph Polchinski
Joseph Gerard Polchinski Jr. (; May 16, 1954 – February 2, 2018) was an American theoretical physicist and string theorist. Biography Polchinski was born in White Plains, New York, the elder of two children to Joseph Gerard Polchinski Sr. (1929–2002), a financial consultant and manager, and Joan (née Thornton), an office worker and homemaker. Polchinski was primarily of Irish descent with his paternal grandfather being Polish. Polchinski graduated from Canyon del Oro High School in Tucson, Arizona, in 1971. He obtained his B.S. degree from Caltech in 1975, and his Ph.D. from the University of California, Berkeley, in 1980 under the supervision of Stanley Mandelstam. He did not publish any papers as a graduate student. After postdoctoral positions at SLAC (1980–82) and Harvard (1982–84) he was a professor at the University of Texas at Austin from 1984 to 1992. From 1992 to March 2017 he was a professor in the Physics Department at the University of California, Santa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
University Of Rome Tor Vergata
University of Rome Tor Vergata, also known as the University of Tor Vergata (), is a public research university located in Rome, Italy. Located in the southeastern suburb of Rome, the university combines a liberal arts tradition with emphasis on career orientation in the field of Economics, Engineering, Mathematics and Physics, Natural Sciences, and Medicine. It was established in 1982 with the goal of providing high-quality education for students preparing to meet the changing needs and opportunities of the workforce. Furthermore, the university campus was designed to reflect the same atmosphere that students would feel on Anglophone campuses. Many professors of the university are important members of the Italian cultural and political environment. Its current rector is Nathan Levialdi Ghiron, a professor at the School of Engineering and former vice-Rector. Origin of the name The university takes its name from the 14th-century farmhouse "Turris Virgata" that was owned by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Type II String Theory
In theoretical physics, type II string theory is a unified term that includes both type IIA strings and type IIB strings theories. Type II string theory accounts for two of the five consistent superstring theories in ten dimensions. Both theories have \mathcal=2 extended supersymmetry which is maximal amount of supersymmetry — namely 32 supercharges — in ten dimensions. Both theories are based on oriented closed strings. On the worldsheet, they differ only in the choice of GSO projection. They were first discovered by Michael Green and John Henry Schwarz in 1982, with the terminology of type I and type II coined to classify the three string theories known at the time. Type IIA string theory At low energies, type IIA string theory is described by type IIA supergravity in ten dimensions which is a non-chiral theory (i.e. left–right symmetric) with (1,1) ''d''=10 supersymmetry; the fact that the anomalies in this theory cancel is therefore trivial. In the 1990 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
First Superstring Revolution
The history of string theory spans several decades of intense research including two superstring revolutions. Through the combined efforts of many researchers, string theory has developed into a broad and varied subject with connections to quantum gravity, particle and condensed matter physics, cosmology, and pure mathematics. 1943–1959: S-matrix theory String theory represents an outgrowth of S-matrix theory, a research program begun by Werner Heisenberg in 1943 following John Archibald Wheeler's 1937 introduction of the S-matrix. Many prominent theorists picked up and advocated S-matrix theory, starting in the late 1950s and throughout the 1960s. The field became marginalized and discarded in the mid-1970s and disappeared in the 1980s. Physicists neglected it because some of its mathematical methods were alien, and because quantum chromodynamics supplanted it as an experimentally better-qualified approach to the strong interactions. The theory presented a radical rethinking ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Michael Green (physicist)
Michael Boris Green (born 22 May 1946) is a British physicist and a pioneer of string theory. He is a professor of theoretical physics in the School of Physics and Astronomy at Queen Mary University of London, emeritus professor in the Department of Applied Mathematics and Theoretical Physics and a Fellow of Clare Hall, Cambridge. He was Lucasian Professor of Mathematics from 2009 to 2015. Early life and education Green was born the son of Genia Green and Absalom Green. He attended William Ellis School in London and Churchill College, Cambridge where he graduated with a Bachelor of Arts with first class honours in theoretical physics (1967) and a PhD in elementary particle theory (1970). Career Following his PhD, Green did postdoctoral research at Princeton University (1970–72), Cambridge and the University of Oxford. Between 1978 and 1993 he was a Lecturer and Professor at Queen Mary College, University of London, and in July 1993 he was appointed John Humphrey Plu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Yang–Mills Theory
Yang–Mills theory is a quantum field theory for nuclear binding devised by Chen Ning Yang and Robert Mills in 1953, as well as a generic term for the class of similar theories. The Yang–Mills theory is a gauge theory based on a special unitary group , or more generally any compact Lie group. A Yang–Mills theory seeks to describe the behavior of elementary particles using these non-abelian Lie groups and is at the core of the unification of the electromagnetic force and weak forces (i.e. ) as well as quantum chromodynamics, the theory of the strong force (based on ). Thus it forms the basis of the understanding of the Standard Model of particle physics. History and qualitative description Gauge theory in electrodynamics All known fundamental interactions can be described in terms of gauge theories, but working this out took decades. Hermann Weyl's pioneering work on this project started in 1915 when his colleague Emmy Noether proved that every conserved physical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Supersymmetric
Supersymmetry is a theoretical framework in physics that suggests the existence of a symmetry between particles with integer spin (''bosons'') and particles with half-integer spin (''fermions''). It proposes that for every known particle, there exists a partner particle with different spin properties. There have been multiple experiments on supersymmetry that have failed to provide evidence that it exists in nature. If evidence is found, supersymmetry could help explain certain phenomena, such as the nature of dark matter and the hierarchy problem in particle physics. A supersymmetric theory is a theory in which the equations for force and the equations for matter are identical. In theoretical and mathematical physics, any theory with this property has the ''principle of supersymmetry'' (SUSY). Dozens of supersymmetric theories exist. In theory, supersymmetry is a type of spacetime symmetry between two basic classes of particles: bosons, which have an integer-valued spin and fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
