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Bryce Seligman 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 method ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinuba, California
Dinuba is a city in Tulare County, California, United States. The population was 21,453 at the 2010 census. It is part of the Visalia-Porterville metropolitan statistical area. The Alta District Museum is located in Dinuba in a restored railroad station; the museum has a collection of materials that illustrate local history. The name of the city is of unknown origin. While various theories about the origin exist, none have been verified. It probably is a fanciful name applied by railroad construction engineers at the time the branch line was built in this area. The city's original name was Sibleyville, named for James Sibley, who deeded 240 acres to the Pacific Improvement Company (Southern Pacific Company). Geography Dinuba is located at (36.544898, -119.389260). According to the United States Census Bureau, the city has a total area of , all of it land. The general topography is quite level ground, at an elevation of approximately above mean sea datum. The gradient i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canonical Quantum Gravity
In physics, canonical quantum gravity is an attempt to quantize the canonical formulation of general relativity (or canonical gravity). It is a Hamiltonian formulation of Einstein's general theory of relativity. The basic theory was outlined by Bryce DeWitt in a seminal 1967 paper, and based on earlier work by Peter G. Bergmann using the so-called canonical quantization techniques for constrained Hamiltonian systems invented by Paul Dirac. Dirac's approach allows the quantization of systems that include gauge symmetries using Hamiltonian techniques in a fixed gauge choice. Newer approaches based in part on the work of DeWitt and Dirac include the Hartle–Hawking state, Regge calculus, the Wheeler–DeWitt equation and loop quantum gravity. Canonical quantization In the Hamiltonian formulation of ordinary classical mechanics the Poisson bracket is an important concept. A "canonical coordinate system" consists of canonical position and momentum variables that satisfy canoni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stanford University
Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is considered among the most prestigious universities in the world. Stanford was founded in 1885 by Leland and Jane Stanford in memory of their only child, Leland Stanford Jr., who had died of typhoid fever at age 15 the previous year. Leland Stanford was a U.S. senator and former governor of California who made his fortune as a railroad tycoon. The school admitted its first students on October 1, 1891, as a coeducational and non-denominational institution. Stanford University struggled financially after the death of Leland Stanford in 1893 and again after much of the campus was damaged by the 1906 San Francisco earthquake. Following World War II, provost of Stanford Frederick Terman inspired and supported faculty and graduates' entrepreneu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Felix Bloch
Felix Bloch (23 October 1905 – 10 September 1983) was a Swiss-American physicist and Nobel physics laureate who worked mainly in the U.S. He and Edward Mills Purcell were awarded the 1952 Nobel Prize for Physics for "their development of new ways and methods for nuclear magnetic precision measurements."Sohlman, M (Ed.) ''Nobel Foundation directory 2003.'' Vastervik, Sweden: AB CO Ekblad; 2003. In 1954–1955, he served for one year as the first Director-General of CERN. Felix Bloch made fundamental theoretical contributions to the understanding of ferromagnetism and electron behavior in crystal lattices. He is also considered one of the developers of nuclear magnetic resonance. Biography Early life, education, and family Bloch was born in Zürich, Switzerland to Jewish parents Gustav and Agnes Bloch. Gustav Bloch, his father, was financially unable to attend University and worked as a wholesale grain dealer in Zürich. Gustav moved to Zürich in 1890 to become a Swiss c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hugh Hamilton DeWitt
Hugh Hamilton DeWitt (28 December 1933-5 January 1995) was an American ichthyologist, marine biologist and oceanographer. DeWitt was born on 28 December 1933 in San Jose, California, son of Carl Bryce Seligman, a country doctor, and Honor Pettit Seligman, a teacher of mathematics and Latin. His surname at birth was Seligman but at his father's urging he and his brothers changed their name to DeWitt in the 1950s, a name from their mother’s side of the family, as they had encountered mistaken preconceptions while attending High Schools in the eastern United States. His brothers were the theoretical physicist Bryce Seligman DeWitt, Lloyd Lewis DeWitt (1926-1988), who joined the United States Foreign Service and Hiram Pettit DeWitt (b.1936), a teacher. He grew up largely in California, leaving to attend high school at the Putney School in Vermont. He returned to California to enrol at Stanford University, gaining his Bachelor's degree in 1955, masters in 1960 and doctorate in 1966, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichthyologist
Ichthyology is the branch of zoology devoted to the study of fish, including bony fish ( Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 33,400 species of fish had been described as of October 2016, with approximately 250 new species described each year. Etymology The word is derived from the Greek words ἰχθύς, ''ikhthus'', meaning "fish"; and λογία, ''logia'', meaning "to study". History The study of fish dates from the Upper Paleolithic Revolution (with the advent of "high culture"). The science of ichthyology was developed in several interconnecting epochs, each with various significant advancements. The study of fish receives its origins from humans' desire to feed, clothe, and equip themselves with useful implements. According to Michael Barton, a prominent ichthyologist and professor at Centre College, "the earliest ichthyologists were ''hunters and gatherers'' who had learned how to obtain the most usef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 in condensed matter physics to construct models of quasiparticles. QFT treats particles as excited states (also called Quantum, quanta) of their underlying quantum field (physics), fields, which are more fundamental than the particles. The equation of motion of the particle is determined by minimization of the Lagrangian, a functional of fields associated with the particle. Interactions between particles are described by interaction terms in the Lagrangian (field theory), Lagrangian involving their corresponding quantum fields. Each interaction can be visually represented by Feynman diagrams according to perturbation theory (quantum mechanics), perturbation theory in quantum mechanics. History Quantum field theory emerged from the wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitation
In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the strong interaction, 1036 times weaker than the electromagnetic force and 1029 times weaker than the weak interaction. As a result, it has no significant influence at the level of subatomic particles. However, gravity is the most significant interaction between objects at the macroscopic scale, and it determines the motion of planets, stars, galaxies, and even light. On Earth, gravity gives weight to physical objects, and the Moon's gravity is responsible for sublunar tides in the oceans (the corresponding antipodal tide is caused by the inertia of the Earth and Moon orbiting one another). Gravity also has many important biological functions, helping to guide the growth of plants through the process of gravitropism and influencing the circul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theoretical Physicist
Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict 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 Einstein was concerned with t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
