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Julian Schwinger
Julian Seymour Schwinger (; February 12, 1918 – July 16, 1994) was a Nobel Prize winning American theoretical physicist. He is best known for his work on quantum electrodynamics (QED), in particular for developing a relativistically invariant perturbation theory, and for renormalizing QED to one loop order. Schwinger was a physics professor at several universities. Schwinger is recognized as one of the greatest physicists of the twentieth century, responsible for much of modern quantum field theory, including a variational approach, and the equations of motion for quantum fields. He developed the first electroweak model, and the first example of confinement in 1+1 dimensions. He is responsible for the theory of multiple neutrinos, Schwinger terms, and the theory of the spin-3/2 field. Biography Early life and career Julian Seymour Schwinger was born in New York City, to Ashkenazi Jewish parents, Belle (née Rosenfeld) and Benjamin Schwinger, a garment manufacturer, who had e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New York City
New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the List of United States cities by population density, most densely populated major city in the United States, and is more than twice as populous as second-place Los Angeles. New York City lies at the southern tip of New York (state), New York State, and constitutes the geographical and demographic center of both the Northeast megalopolis and the New York metropolitan area, the largest metropolitan area in the world by urban area, urban landmass. With over 20.1 million people in its metropolitan statistical area and 23.5 million in its combined statistical area as of 2020, New York is one of the world's most populous Megacity, megacities, and over 58 million people live within of the city. New York City is a global city, global Culture of New ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bryce DeWitt
Bryce Seligman DeWitt (January 8, 1923 – September 23, 2004), was an American theoretical physicist noted for his work in gravitation and quantum field theory. Life He was born Carl Bryce Seligman, but he and his three brothers, including the noted ichthyologist Hugh Hamilton DeWitt, added "DeWitt" from their mother's side of the family, at the urging of their father, in 1950. In the early-1970s, this change of name so angered Felix Bloch that he blocked DeWitt's appointment to Stanford University and DeWitt and his wife Cecile DeWitt-Morette, a mathematical physicist, accepted faculty positions at the University of Texas at Austin. DeWitt served in World War II as a naval aviator. He died September 23, 2004 from pancreatic cancer at the age of 81. He is buried in France, and was survived by his wife and four daughters. Work He pioneered work in the quantization of general relativity and, in particular, developed canonical quantum gravity, manifestly covariant methods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spin–statistics Theorem
In quantum mechanics, the spin–statistics theorem relates the intrinsic spin of a particle (angular momentum not due to the orbital motion) to the particle statistics it obeys. In units of the reduced Planck constant ''ħ'', all particles that move in 3 dimensions have either integer spin or half-integer spin. Background Quantum states and indistinguishable particles In a quantum system, a physical state is described by a state vector. A pair of distinct state vectors are physically equivalent if they differ only by an overall phase factor, ignoring other interactions. A pair of indistinguishable particles such as this have only one state. This means that if the positions of the particles are exchanged (i.e., they undergo a permutation), this does not identify a new physical state, but rather one matching the original physical state. In fact, one cannot tell which particle is in which position. While the physical state does not change under the exchange of the particles' po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cavity Perturbation Theory
In mathematics and electronics, Cavity perturbation theory describes methods for derivation of perturbation formulae for performance changes of a cavity resonator. These performance changes are assumed to be caused by either introduction of a small foreign object into the cavity, or a small deformation of its boundary. Various mathematical methods can be used to study the characteristics of cavities, which are important in the field of microwave systems, and more generally in the field of electro magnetism. There are many industrial applications for cavity resonators, including microwave ovens, microwave communication systems, and remote imaging systems using electro magnetic waves. How a resonant cavity performs can affect the amount of energy that is required to make it resonate, or the relative stability or instability of the system. Introduction When a resonant cavity is perturbed, e.g. by introducing a foreign object with distinct material properties into the cavity or when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electroweak Interaction
In particle physics, the electroweak interaction or electroweak force is the unified description of two of the four known fundamental interactions of nature: electromagnetism and the weak interaction. Although these two forces appear very different at everyday low energies, the theory models them as two different aspects of the same force. Above the unification energy, on the order of 246 GeV,The particular number 246 GeV is taken to be the vacuum expectation value v = (G_\text \sqrt)^ of the Higgs field (where G_\text is the Fermi coupling constant). they would merge into a single force. Thus, if the temperature is high enough – approximately 1015 K – then the electromagnetic force and weak force merge into a combined electroweak force. During the quark epoch (shortly after the Big Bang), the electroweak force split into the electromagnetic and weak force. It is thought that the required temperature of 1015 K has not been seen widely throughout the unive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Electrodynamics
In particle physics, quantum electrodynamics (QED) is the relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and special relativity is achieved. QED mathematically describes all phenomena involving electrically charged particles interacting by means of exchange of photons and represents the quantum counterpart of classical electromagnetism giving a complete account of matter and light interaction. In technical terms, QED can be described as a perturbation theory of the electromagnetic quantum vacuum. Richard Feynman called it "the jewel of physics" for its extremely accurate predictions of quantities like the anomalous magnetic moment of the electron and the Lamb shift of the energy levels of hydrogen. History The first formulation of a quantum theory describing radiation and matter interaction is attributed to British scientist Paul Dirac, who ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles M
Charles is a masculine given name predominantly found in English and French speaking countries. It is from the French form ''Charles'' of the Proto-Germanic name (in runic alphabet) or ''*karilaz'' (in Latin alphabet), whose meaning was "free man". The Old English descendant of this word was '' Ċearl'' or ''Ċeorl'', as the name of King Cearl of Mercia, that disappeared after the Norman conquest of England. The name was notably borne by Charlemagne (Charles the Great), and was at the time Latinized as ''Karolus'' (as in ''Vita Karoli Magni''), later also as '' Carolus''. Some Germanic languages, for example Dutch and German, have retained the word in two separate senses. In the particular case of Dutch, ''Karel'' refers to the given name, whereas the noun ''kerel'' means "a bloke, fellow, man". Etymology The name's etymology is a Common Germanic noun ''*karilaz'' meaning "free man", which survives in English as churl (< Old English ''ċeorl''), which developed its dep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tung-Mow Yan
Tung-Mow Yan (; born 1937) is a Taiwanese-born American physicist, who has specialized in theoretical particle physics; primarily in the structure of elementary particles, the standard model, and quantum chromodynamics. He is professor emeritus at Cornell University. Education He graduated with a BS in physics in 1960 at National Taiwan University (NTU), an MS in physics at National Tsing Hua University (Hsinchu) in 1962, and earned a Ph.D. in physics in 1968 at Harvard University, under the supervision of Julian Schwinger. Research From 1970 to 2009 Yan worked at Cornell University, in particular the Cornell High-Energy Synchrotron Source and Laboratory for Elementary-Particle Physics (combined into the Cornell Laboratory for Accelerator-based Sciences and Education as of 2006). He became a professor in 19??. By 2010 he reached the status of professor emeritus in physics. Other affiliations during Yan's life and work are: *1968–1970: research associate at SLAC *1973–1974: v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Margaret G
Margaret is a female first name, derived via French () and Latin () from grc, μαργαρίτης () meaning "pearl". The Greek is borrowed from Persian. Margaret has been an English name since the 11th century, and remained popular throughout the Middle Ages. It became less popular between the 16th century and 18th century, but became more common again after this period, becoming the second-most popular female name in the United States in 1903. Since this time, it has become less common, but was still the ninth-most common name for women of all ages in the United States as of the 1990 census. Margaret has many diminutive forms in many different languages, including Maggie, Madge, Daisy, Margarete, Marge, Margo, Margie, Marjorie, Meg, Megan, Rita, Greta, Gretchen, and Peggy. Name variants Full name * (Irish) * (Irish) * (Dutch), (German), (Swedish) * (English) Diminutives * (English) * (English) First half * ( French) * (Welsh) Second half * (English), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lawrence Paul Horwitz
Lawrence Paul Horwitz (born October 14, 1930) is an American/Israeli physicist and mathematician who has made contributions in particle physics, statistical mechanics, mathematical physics, theory of unstable systems, classical chaos and quantum chaos, relativistic quantum mechanics, quantum field theory In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines classical field theory, special relativity, and quantum mechanics. QFT is used in particle physics to construct physical models of subatomic particles and ..., general relativity, representations of quantum theory on hypercomplex Hilbert modules, group theory and functional analysis and stochastic theories of irreversible quantum evolution. After obtaining his Ph.D. at Harvard University under Julian Schwinger, he worked at the IBM Research Laboratory in Yorktown, New York, Yorktown, New York (state), New York until 1964. He then worked at the Department of Theoretical Physics at the U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stanley Deser
Stanley Deser (born 1931) is an American physicist known for his contributions to general relativity. Currently, he is emeritus Ancell Professor of Physics at Brandeis University in Waltham, Massachusetts and a senior research associate at California Institute of Technology. Biography Deser earned his B.A. (Summa cum laude) in 1949 at Brooklyn College in New York, and his master's degree 1950 at Harvard, where he also earned his doctorate in 1953, with a thesis entitled "Relativistic Two Body Interactions". From 1953 to 1955, he was at the Institute for Advanced Study in Princeton. He was at the Niels Bohr Institute from 1955 to 1957, and a lecturer at Harvard from 1957 to 1958. He was an invited professor at the Sorbonne during 1966–1967 and 1971–1972, he held a visiting professorship at All Souls College in Oxford in 1977, and a Loeb Lectureship at Harvard in 1975. In the context of general relativity, he developed, with Richard Arnowitt and Charles Misner, the ADM form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lowell S
Lowell may refer to: Places United States * Lowell, Arkansas * Lowell, California * Lowell, Florida * Lowell, Idaho * Lowell, Indiana * Lowell, Bartholomew County, Indiana * Lowell, Maine * Lowell, Massachusetts ** Lowell National Historical Park ** Lowell (MBTA station) ** Lowell Ordnance Plant * Lowell, Michigan * Lowell, North Carolina * Lowell, Washington County, Ohio * Lowell, Seneca County, Ohio * Lowell, Oregon * Lowell, Vermont, a New England town ** Lowell (CDP), Vermont, the main village in the town * Lowell, West Virginia * Lowell (town), Wisconsin Lowell is a town in Dodge County, Wisconsin, United States. The population was 1,169 at the 2000 census. The Village of Lowell is located within the town. The unincorporated community of North Lowell is located in the town. Geography According t ... ** Lowell, Wisconsin, a village within the town of Lowell * Lowell Hill, California * Lowell Point, Alaska *Lowell Township (other) Other countries * Lowel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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