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Dirac Hole Theory
Dirac hole theory is a theory in quantum mechanics, named after English theoretical physicist Paul Dirac. The theory poses that the continuum of negative energy states, that are solutions to the Dirac equation, are filled with electrons, and the vacancies in this continuum (holes) are manifested as positrons with energy and momentum that are the negative of those of the state. The discovery of the positron in 1929 gave a considerable support to the Dirac hole theory. While Enrico Fermi, Niels Bohr and Wolfgang Pauli were skeptical about the theory, other physicists, like Guido Beck and Kurt Sitte, made use of Dirac hole theory in alternative theories of beta decay. Gian Wick extended Dirac hole theory to cover neutrinos, introducing the anti-neutrino as a hole in a neutrino Dirac sea The Dirac sea is a theoretical model of the vacuum as an infinite sea of particles with negative energy. It was first postulated by the British physicist Paul Dirac in 1930 to explain the anomalo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Mechanics
Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, quantum field theory, quantum technology, and quantum information science. Classical physics, the collection of theories that existed before the advent of quantum mechanics, describes many aspects of nature at an ordinary (macroscopic) scale, but is not sufficient for describing them at small (atomic and subatomic) scales. Most theories in classical physics can be derived from quantum mechanics as an approximation valid at large (macroscopic) scale. Quantum mechanics differs from classical physics in that energy, momentum, angular momentum, and other quantities of a bound system are restricted to discrete values ( quantization); objects have characteristics of both particles and waves (wave–particle duality); and there are limits to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Niels Bohr
Niels Henrik David Bohr (; 7 October 1885 – 18 November 1962) was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922. Bohr was also a philosopher and a promoter of scientific research. Bohr developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another. Although the Bohr model has been supplanted by other models, its underlying principles remain valid. He conceived the principle of complementarity: that items could be separately analysed in terms of contradictory properties, like behaving as a wave or a stream of particles. The notion of complementarity dominated Bohr's thinking in both science and philosophy. Bohr founded the Institute of Theoretical Physics at the University of Cope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-neutrino
A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small ('' -ino'') that it was long thought to be zero. The rest mass of the neutrino is much smaller than that of the other known elementary particles excluding massless particles. The weak force has a very short range, the gravitational interaction is extremely weak due to the very small mass of the neutrino, and neutrinos do not participate in the strong interaction. Thus, neutrinos typically pass through normal matter unimpeded and undetected. Weak interactions create neutrinos in one of three leptonic flavors: electron neutrinos muon neutrinos (), or tau neutrinos (), in association with the corresponding charged lepton. Although neutrinos were long believed to be massless, it is now known that there are three discrete neut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutrinos
A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small ('' -ino'') that it was long thought to be zero. The rest mass of the neutrino is much smaller than that of the other known elementary particles excluding massless particles. The weak force has a very short range, the gravitational interaction is extremely weak due to the very small mass of the neutrino, and neutrinos do not participate in the strong interaction. Thus, neutrinos typically pass through normal matter unimpeded and undetected. Weak interactions create neutrinos in one of three leptonic flavors: electron neutrinos muon neutrinos (), or tau neutrinos (), in association with the corresponding charged lepton. Although neutrinos were long believed to be massless, it is now known that there are three discrete ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gian Wick
Gian is a masculine Italian given name. It is a variant of Gianni and is likewise used as a diminutive of Giovanni, the Italian form of John. In Italian, any name including Giovanni can be contracted to Gian, particularly in combination with other given names, such as Gianfranco or Gianluca. Gian is also an unrelated masculine Punjabi Sikh name meaning 'knowledge' and is a variant of the Sanskrit name Gyan. Notable people Notable people whose name is now typically expressed as Gian include: * Gian Paolo Lomazzo, Italian painter * Gian Lorenzo Bernini, Italian sculptor * Gian Rinaldo Carli, Italian count, economist, and antiquarian * Gian Gastone de' Medici, Grand Duke of Tuscany * Gian Francesco Albani, Italian Catholic cardinal * Gian Francesco Malipiero, Italian composer * Gian Galeazzo Visconti, First Lord of Milan * Gian Galeazzo Sforza, Sixth Lord of Milan * Gian Marco Centinaio, Italian politician * Gian Pyres, British musician * Gian Maria Volonté, former actor * Gian Sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Decay
In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For example, beta decay of a neutron transforms it into a proton by the emission of an electron accompanied by an antineutrino; or, conversely a proton is converted into a neutron by the emission of a positron with a neutrino in so-called ''positron emission''. Neither the beta particle nor its associated (anti-)neutrino exist within the nucleus prior to beta decay, but are created in the decay process. By this process, unstable atoms obtain a more stable ratio of protons to neutrons. The probability of a nuclide decaying due to beta and other forms of decay is determined by its nuclear binding energy. The binding energies of all existing nuclides form what is called the nuclear band or valley of stability. For either electron or positron em ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kurt Sitte
Kurt Sitte (1 December 1910 - 20 June 1993) was a nuclear physicist, originally from northern Bohemia. As a result of frontier changes, he grew up, after 1919, in Czechoslovakia, and from 1938 found himself a citizen of an enlarged Germany. It was primarily because of his political activism that he was detained at the Buchenwald concentration camp between September 1939 and April 1944. Having survived this internment, his scientific skills opened up a range of career options internationally: between 1945 he lived and worked successively in Scotland, England, the United States, Brazil and Israel. Kurt Sitte was arrested on espionage charges on 15 June 1960 and, as Israel's first convicted spy, spent the next three and a half years in prison. Early release, in March 1963, resulted from his "good behaviour", at which point he was quoted as saying that he would be "glad" to continue to work in Israel, but shortly after this he took West German citizenship and relocated to Freibu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guido Beck
Guido Beck (29 August 1903 in Liberec – 21 October 1988 in Rio de Janeiro) was an Argentinian physicist of German Bohemian origin. Biography Beck studied physics in Vienna and received his doctorate in 1925, under Hans Thirring. He worked in Leipzig in 1928 as an assistant to Werner Heisenberg. A combination of the troubled political climate of Europe in the 1930s, his own restlessness, and the Nazi persecutions in Germany, made the Jewish-born Beck a traveler in those years. Until 1935 he worked in Cambridge with Ernest Rutherford, Copenhagen, Prague, United States and Japan. In 1935, Beck was invited to work in the Soviet Union by Head of the Institute of Physics, Odessa University Yelpidifor Anempodistovich Kirillov. At the Odessa University Beck was head of the Department of Theoretical Physics and gave a course of theoretical physics in German; his lectures were simultaneously translated into Ukrainian by his assistant Yu.G. Vekshtein. In 1936–1937 Beck was head of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wolfgang Pauli
Wolfgang Ernst Pauli (; ; 25 April 1900 – 15 December 1958) was an Austrian theoretical physicist and one of the pioneers of quantum physics. In 1945, after having been nominated by Albert Einstein, Pauli received the Nobel Prize in Physics for his "decisive contribution through his discovery of a new law of Nature, the exclusion principle or Pauli principle". The discovery involved spin theory, which is the basis of a theory of the structure of matter. Early years Pauli was born in Vienna to a chemist, Wolfgang Joseph Pauli (''né'' Wolf Pascheles, 1869–1955), and his wife, Bertha Camilla Schütz; his sister was Hertha Pauli, a writer and actress. Pauli's middle name was given in honor of his godfather, physicist Ernst Mach. Pauli's paternal grandparents were from prominent families of Prague; his great-grandfather was the publisher Wolf Pascheles. Pauli's mother, Bertha Schütz, was raised in her mother's Roman Catholic religion; Pauli was raised as a Roman Catholic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enrico Fermi
Enrico Fermi (; 29 September 1901 – 28 November 1954) was an Italian (later naturalized American) physicist and the creator of the world's first nuclear reactor, the Chicago Pile-1. He has been called the "architect of the nuclear age" and the "architect of the atomic bomb". He was one of very few physicists to excel in both theoretical physics and experimental physics. Fermi was awarded the 1938 Nobel Prize in Physics for his work on induced radioactivity by neutron bombardment and for the discovery of transuranium elements. With his colleagues, Fermi filed several patents related to the use of nuclear power, all of which were taken over by the US government. He made significant contributions to the development of statistical mechanics, Quantum mechanics, quantum theory, and nuclear physics, nuclear and particle physics. Fermi's first major contribution involved the field of statistical mechanics. After Wolfgang Pauli formulated his Pauli exclusion principle, exclusion pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Dirac
Paul Adrien Maurice Dirac (; 8 August 1902 – 20 October 1984) was an English theoretical physicist who is regarded as one of the most significant physicists of the 20th century. He was the Lucasian Professor of Mathematics at the University of Cambridge, a professor of physics at Florida State University and the University of Miami, and a 1933 Nobel Prize recipient. Dirac made fundamental contributions to the early development of both quantum mechanics and quantum electrodynamics. Among other discoveries, he formulated the Dirac equation which describes the behaviour of fermions and predicted the existence of antimatter. Dirac shared the 1933 Nobel Prize in Physics with Erwin Schrödinger "for the discovery of new productive forms of atomic theory". He also made significant contributions to the reconciliation of general relativity with quantum mechanics. Dirac was regarded by his friends and colleagues as unusual in character. In a 1926 letter to Paul Ehrenfest, Albert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of California, San Diego
The University of California, San Diego (UC San Diego or colloquially, UCSD) is a public university, public Land-grant university, land-grant research university in San Diego, California. Established in 1960 near the pre-existing Scripps Institution of Oceanography, UC San Diego is the southernmost of the ten campuses of the University of California, and offers over 200 undergraduate and graduate degree programs, enrolling 33,096 undergraduate and 9,872 graduate students. The university occupies near the coast of the Pacific Ocean, with the main campus resting on approximately . UC San Diego is ranked among the best universities in the world by major college and university rankings. UC San Diego consists of twelve undergraduate, graduate and professional schools as well as seven undergraduate residential colleges. It received over 140,000 applications for undergraduate admissions in Fall 2021, making it the second most applied-to university in the United States. UC San Diego H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
