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Augusto Sagnotti
Augusto Sagnotti (born 1955) is an Italians, Italian theoretical physics, theoretical physicist at Scuola Normale Superiore di Pisa, Scuola Normale (since 2005). Biography Sagnotti earned a Laurea in Electrical Engineering from the Sapienza University of Rome, University of Rome "La Sapienza" in 1978 (advisors: Bruno Crosignani and Paolo Di Porto); and a Ph.D. in Theoretical Physics from Caltech in 1983 (advisor: John H. Schwarz). He was Post-Doctoral Fellow at Caltech (1983–84) and Miller Research Fellow at U.C. Berkeley (1984–86). Sagnotti was Junior Faculty at the University of Rome "Tor Vergata" from 1986 to 1994, then Associate Professor (1994–99) and Professor (2000-2005). His research activity has been devoted to the Quantization (physics), quantization of the gravitational field, to String Theory, to Conformal Field Theory and to AdS/CFT correspondence#Higher spin gauge theories, Higher-Spin Gauge Fields. Sagnotti's main contribution to physics is perhaps the analys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rome, Italy
, established_title = Founded , established_date = 753 BC , founder = King Romulus (Romulus and Remus, legendary) , image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg , map_caption = The territory of the ''comune'' (''Roma Capitale'', in red) inside the Metropolitan City of Rome (''Città Metropolitana di Roma'', in yellow). The white spot in the centre is Vatican City. , pushpin_map = Italy#Europe , pushpin_map_caption = Location within Italy##Location within Europe , pushpin_relief = yes , coordinates = , coor_pinpoint = , subdivision_type = List of sovereign states, Country , subdivision_name = Italy , subdivision_type2 = Regions of Italy, Region , subdivision_name2 = Lazio , subdivision_type3 = Metropolitan cities of Italy, Metropolitan city , subdivision_name3 = Metropolitan City of Rome Capital, Rome Capital , government_footnotes= , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Relativity
General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time or four-dimensional spacetime. In particular, the ' is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of second order partial differential equations. Newton's law of universal gravitation, which describes classical gravity, can be seen as a prediction of general relativity for the almost flat spacetime geometry around stationary mass distributions. Some predictions of general relativity, however, are beyond Newton's law of universal gravitat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proceedings Supplements
In academia and librarianship, conference proceedings is a collection of academic papers published in the context of an academic conference or workshop. Conference proceedings typically contain the contributions made by researchers at the conference. They are the written record of the work that is presented to fellow researchers. In many fields, they are published as supplements to academic journals; in some, they are considered the main dissemination route; in others they may be considered grey literature. They are usually distributed in printed or electronic volumes, either before the conference opens or after it has closed. A less common, broader meaning of proceedings are the acts and happenings of an academic field, a learned society. For example, the title of the '' Acta Crystallographica'' journals is New Latin for "Proceedings in Crystallography"; the '' Proceedings of the National Academy of Sciences of the United States of America'' is the main journal of that aca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tachyon
A tachyon () or tachyonic particle is a hypothetical particle that always travels faster than light. Physicists believe that faster-than-light particles cannot exist because they are not consistent with the known laws of physics. If such particles did exist they could be used to send signals faster than light. According to the theory of relativity this would violate causality, leading to logical paradoxes such as the grandfather paradox. Tachyons would exhibit the unusual property of increasing in speed as their energy decreases, and would require infinite energy to slow down to the speed of light. No verifiable experimental evidence for the existence of such particles has been found. In the 1967 paper that coined the term, Gerald Feinberg proposed that tachyonic particles could be made from excitations of a quantum field with imaginary mass. However, it was soon realized that Feinberg's model did not in fact allow for superluminal (faster-than-light) particles or signals and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strings 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 condense ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type 0 String Theory
The Type 0 string theory is a less well-known model of string theory. It is a superstring theory in the sense that the worldsheet theory is supersymmetric. However, the spacetime spectrum is not supersymmetric and, in fact, does not contain any fermions at all. In dimensions greater than two, the ground state is a tachyon so the theory is unstable. These properties make it similar to the bosonic string and an unsuitable proposal for describing the world as we observe it, although a GSO projection does get rid of the tachyon and the even G-parity sector of the theory defines a stable string theory. The theory is used sometimes as a toy model for exploring concepts in string theory, notably closed string tachyon condensation. Some other recent interest has involved the two-dimensional Type 0 string which has a non-perturbatively stable matrix model description. Like the Type II string, different GSO projection The GSO projection (named after Ferdinando Gliozzi, Joël Scherk, and Da ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics Reports
''Physics Reports'' is a peer-reviewed scientific journal, a review section of ''Physics Letters'' that has been published by Elsevier since 1971. The journal publishes long and deep reviews on all aspects of physics. In average, the length of these reports is the same of a short book. These reports aim to make their main points intelligible to non-specialists. According to the ''Journal Citation Reports'', the journal has a 2020 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 25.6, as reported in the official website of the Journal. References External links * Physics review journals Elsevier academic journals English-language journals Publications established in 1971 Weekly journals {{physics-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. In quantum theory, the first anomaly discovered was the Adler–Bell–Jackiw anomaly, wherein the axial vector current is conserved as a classical symmetry of electrodynamics, but is broken by the quantized theory. The relationship of this anomaly to the Atiyah–Singer index theorem was one of the celebrated achievements of the theory. Technically, an anomalous symmetry in a quantum theory is a symmetry of the action, but not of the measure, and so not of the partition fu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D9-brane
In string theory, D-branes, short for ''Dirichlet membrane'', are a class of extended objects upon which open string (physics), strings can end with Dirichlet boundary conditions, after which they are named. D-branes were discovered by Jin Dai, Robert Leigh, Leigh, and Joseph Polchinski, Polchinski, and independently by Petr Hořava (theorist), 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 principle, holographic and M-theory dualities. 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. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plenum Publishing Corporation
Springer Science+Business Media, commonly known as Springer, is a German multinational publishing company of books, e-books and peer-reviewed journals in science, humanities, technical and medical (STM) publishing. Originally founded in 1842 in Berlin, it expanded internationally in the 1960s, and through mergers in the 1990s and a sale to venture capitalists it fused with Wolters Kluwer and eventually became part of Springer Nature in 2015. Springer has major offices in Berlin, Heidelberg, Dordrecht, and New York City. History Julius Springer founded Springer-Verlag in Berlin in 1842 and his son Ferdinand Springer grew it from a small firm of 4 employees into Germany's then second largest academic publisher with 65 staff in 1872.Chronology ". Springer Science+Business Media. In 1964, Springer expanded its business internationally, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type IIB String
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 the 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. 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 1990s it was realized by Edward Witten (building on previous insights by Michael Duff, Paul Townsend, and others) that the limit of type IIA string theory in which the string coupling goes to infinity becomes a new 11-dimensional th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orientifold
In theoretical physics orientifold is a generalization of the notion of orbifold, proposed by Augusto Sagnotti in 1987. The novelty is that in the case of string theory the non-trivial element(s) of the orbifold group includes the reversal of the orientation of the string. Orientifolding therefore produces unoriented strings—strings that carry no "arrow" and whose two opposite orientations are equivalent. Type I string theory is the simplest example of such a theory and can be obtained by orientifolding type IIB string theory. In mathematical terms, given a smooth manifold \mathcal, two discrete, freely acting, groups G_ and G_ and the worldsheet parity operator \Omega_ (such that \Omega_ : \sigma \to 2\pi - \sigma) an orientifold is expressed as the quotient space \mathcal/(G_ \cup \Omega G_). If G_ is empty, then the quotient space is an orbifold. If G_ is not empty, then it is an orientifold. Application to string theory In string theory \mathcal is the compact space form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
