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Supergravity
In theoretical physics, supergravity (supergravity theory; SUGRA for short) is a modern field theory that combines the principles of supersymmetry and general relativity; this is in contrast to non-gravitational supersymmetric theories such as the Minimal Supersymmetric Standard Model. Supergravity is the gauge theory of local supersymmetry. Since the supersymmetry (SUSY) generators form together with the Poincaré algebra and superalgebra, called the super-Poincaré algebra, supersymmetry as a gauge theory makes gravity arise in a natural way. Gravitons Like all covariant approaches to quantum gravity, supergravity contains a spin-2 field whose quantum is the graviton. Supersymmetry requires the graviton field to have a superpartner. This field has spin 3/2 and its quantum is the gravitino. The number of gravitino fields is equal to the number of supersymmetries. History Gauge supersymmetry The first theory of local supersymmetry was proposed by Dick Arnowitt and Pra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supersymmetry
Supersymmetry is a Theory, theoretical framework in physics that suggests the existence of a symmetry between Particle physics, particles with integer Spin (physics), 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 physics, 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 symmetries, spacetime symmetry betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ali Chamseddine
Ali H. Chamseddine (, born 20 February 1953) is a Lebanese physicist known for his contributions to particle physics, general relativity and mathematical physics. , Chamseddine is a physics Professor at the American University of Beirut and the Institut des hautes études scientifiques. Education and working positions Ali H. Chamseddine was born in 1953 in the town of Joun, Lebanon. He received his BSc in Physics from the Lebanese University in July 1973. After receiving a scholarship from the Lebanese University to continue his graduate studies in Physics at Imperial College London, Chamseddine received a Diploma in Physics in June 1974, under the supervision of Tom Kibble. After that, Chamseddine did his PhD in Theoretical Physics at Imperial College London as well, in September 1976, where he studied under supervision of Nobel Prize winner Abdus Salam. Later on, Chamseddine did his post-doctoral studies at the Abdus Salam International Centre for Theoretical Physics (ICTP) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sergio Ferrara
Sergio Ferrara (born 2 May 1945) is an Italian physicist working on theoretical physics of elementary particles and mathematical physics. He is renowned for the discovery of theories introducing supersymmetry as a symmetry of elementary particles (super- Yang–Mills theories, together with Bruno Zumino) and of supergravity, the first significant extension of Einstein's general relativity, based on the principle of "local supersymmetry" (together with Daniel Z. Freedman, and Peter van Nieuwenhuizen). He is an emeritus staff member at CERN and a professor emeritus at the University of California, Los Angeles. Career Sergio Ferrara was born on 2 May 1945 in Rome, Italy. He graduated from the University of Rome, obtaining in 1968 the Laurea Degree (the highest Degree that was awarded in Italy at the time). Since then he has worked as a CNEN and INFN researcher at the Frascati National Laboratories; as a CNRS Visiting Scientist at the Laboratoire de Physique Théorique, École ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Van Nieuwenhuizen
Peter van Nieuwenhuizen (; born October 26, 1938) is a Dutch theoretical physicist. He is a distinguished Professor at Stony Brook University in the United States. Widely known for his contributions to String theory, Supersymmetry, Supergravity and Field theory. He is best known for his discovery of supergravity with Sergio Ferrara and Daniel Z. Freedman for which he along with his collaborators won the Breakthrough Prize in Fundamental Physics in 2019. Life and career Peter van Nieuwenhuizen studied physics and mathematics at the University of Utrecht, where he obtained in 1971 his Ph.D. under the supervision of later Nobel laureate Martinus Veltman. After his studies in Utrecht he went to CERN (Geneva), the University of Paris in Orsay, and Brandeis University (Waltham). In 1975 he joined the Institute for Theoretical Physics, now named C. N. Yang Institute for Theoretical Physics, of the Stony Brook University, where he succeeded Nobel laureate C. N. Yang as its di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pran Nath (physicist)
Pran Nath is a theoretical physicist working at Northeastern University, with research focus in elementary particle physics. He holds a Matthews Distinguished University Professor chair. Research His main area of research is in the fields of supergravity and particle physics beyond the standard model. He is one of the originators of the first supergravity theory in 1975. In 1982 in collaboration with Richard Arnowitt and Ali Chamseddine, Ali Hani Chamseddine, he developed the field of Applied Supergravity and the supergravity grand unification popularly known as SUGRA or mSUGRA model for gravity mediated breaking of supersymmetry. SUGRA models, and specifically mSUGRA, are currently the leading candidates for discovery at the Fermilab Tevatron and at the CERN Large Hadron Collider (LHC). He has contributed to further development of the field through studies of CP violation, predictions on muon anomalous moment gμ − 2 ahead of experiment, supersymmetric dark matter, discovery o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitino
In supergravity theories combining general relativity and supersymmetry, the gravitino () is the gauge fermion supersymmetric partner of the hypothesized graviton. It has been suggested as a candidate for dark matter. If it exists, it is a fermion of spin and therefore obeys the Rarita–Schwinger equation. The gravitino field is conventionally written as ''ψμα'' with a four-vector index and a spinor index. For one would get negative norm modes, as with every massless particle of spin 1 or higher. These modes are unphysical, and for consistency there must be a gauge symmetry which cancels these modes: , where ''εα''(''x'') is a spinor function of spacetime. This gauge symmetry is a local supersymmetry transformation, and the resulting theory is supergravity. Thus the gravitino is the fermion mediating supergravity interactions, just as the photon is mediating electromagnetism, and the graviton is presumably mediating gravitation. Whenever supersymmetry is br ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kaluza–Klein Theory
In physics, Kaluza–Klein theory (KK theory) is a classical unified field theory of gravitation and electromagnetism built around the idea of a fifth dimension beyond the common 4D of space and time and considered an important precursor to string theory. In their setup, the vacuum has the usual 3 dimensions of space and one dimension of time but with another microscopic extra spatial dimension in the shape of a tiny circle. Gunnar Nordström had an earlier, similar idea. But in that case, a fifth component was added to the electromagnetic vector potential, representing the Newtonian gravitational potential, and writing the Maxwell equations in five dimensions. The five-dimensional (5D) theory developed in three steps. The original hypothesis came from Theodor Kaluza, who sent his results to Albert Einstein in 1919 and published them in 1921. Kaluza presented a purely classical extension of general relativity to 5D, with a metric tensor of 15 components. Ten components are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pure 4D N = 1 Supergravity
In supersymmetry, pure 4D \mathcal N=1 supergravity describes the simplest Four-dimensional space, four-dimensional supergravity, with a single supercharge and a supermultiplet containing a graviton and gravitino. The action (physics), action consists of the Einstein–Hilbert action and the Rarita–Schwinger equation, Rarita–Schwinger action. The theory was first formulated by Daniel Z. Freedman, Peter van Nieuwenhuizen, and Sergio Ferrara, and independently by Stanley Deser and Bruno Zumino in 1976. The only consistent extension to spacetimes with a cosmological constant is to anti-de Sitter space, first formulated by Paul Townsend in 1977. When additional matter supermultiplets are included in this theory, the result is known as 4D N = 1 supergravity, matter-coupled 4D \mathcal N = 1 supergravity. Flat spacetime To describe the coupling between gravity and particles of arbitrary spin (physics), spin, it is useful to use the tetrad formalism, vielbein formalism of general ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Super-Poincaré Algebra
In theoretical physics, a super-Poincaré algebra is an extension of the Poincaré algebra to incorporate supersymmetry, a relation between bosons and fermions. They are examples of supersymmetry algebras (without central charges or internal symmetries), and are Lie superalgebras. Thus a super-Poincaré algebra is a Z2-graded vector space with a graded Lie bracket such that the even part is a Lie algebra containing the Poincaré algebra, and the odd part is built from spinors on which there is an anticommutation relation with values in the even part. Informal sketch The Poincaré algebra describes the isometries of Minkowski spacetime. From the representation theory of the Lorentz group, it is known that the Lorentz group admits two inequivalent complex spinor representations, dubbed 2 and \overline.The barred representations are conjugate linear while the unbarred ones are complex linear. The numeral refers to the dimension of the representation space. Another more common no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Higher-dimensional
In physics and mathematics, the dimension of a mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any point within it. Thus, a line has a dimension of one (1D) because only one coordinate is needed to specify a point on itfor example, the point at 5 on a number line. A surface, such as the boundary of a cylinder or sphere, has a dimension of two (2D) because two coordinates are needed to specify a point on itfor example, both a latitude and longitude are required to locate a point on the surface of a sphere. A two-dimensional Euclidean space is a two-dimensional space on the plane. The inside of a cube, a cylinder or a sphere is three-dimensional (3D) because three coordinates are needed to locate a point within these spaces. In classical mechanics, space and time are different categories and refer to absolute space and time. That conception of the world is a four-dimensional space but not the one that was found nec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
