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Light-front Quantization Applications
The light-front quantization of quantum field theories provides a useful alternative to ordinary equal-time quantization. In particular, it can lead to a relativistic description of bound systems in terms of quantum-mechanical wave functions. The quantization is based on the choice of light-front coordinates, where x^+\equiv ct+z plays the role of time and the corresponding spatial coordinate is x^-\equiv ct-z. Here, t is the ordinary time, z is a Cartesian coordinate, and c is the speed of light. The other two Cartesian coordinates, x and y, are untouched and often called transverse or perpendicular, denoted by symbols of the type \vec x_\perp = (x,y). The choice of the frame of reference where the time t and z-axis are defined can be left unspecified in an exactly soluble relativistic theory, but in practical calculations some choices may be more suitable than others. The basic formalism is discussed elsewhere. There are many applications of this technique, some of which a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
World Line
The world line (or worldline) of an object is the path that an object traces in 4-dimensional spacetime. It is an important concept of modern physics, and particularly theoretical physics. The concept of a "world line" is distinguished from concepts such as an "orbit" or a " trajectory" (e.g., a planet's ''orbit in space'' or the ''trajectory'' of a car on a road) by inclusion of the dimension ''time'', and typically encompasses a large area of spacetime wherein paths which are straight perceptually are rendered as curves in spacetime to show their (relatively) more absolute position states—to reveal the nature of special relativity or gravitational interactions. The idea of world lines was originated by physicists and was pioneered by Hermann Minkowski. The term is now used most often in the context of relativity theories (i.e., special relativity and general relativity). Usage in physics A world line of an object (generally approximated as a point in space, e.g., a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Nuclear Shell Model
In nuclear physics, atomic physics, and nuclear chemistry, the nuclear shell model utilizes the Pauli exclusion principle to model the structure of atomic nuclei in terms of energy levels. The first shell model was proposed by Dmitri Ivanenko (together with E. Gapon) in 1932. The model was developed in 1949 following independent work by several physicists, most notably Maria Goeppert Mayer and J. Hans D. Jensen, who received the 1963 Nobel Prize in Physics for their contributions to this model, and Eugene Wigner, who received the Nobel Prize alongside them for his earlier groundlaying work on the atomic nuclei. The nuclear shell model is partly analogous to the atomic shell model, which describes the arrangement of electrons in an atom, in that a filled shell results in better stability. When adding nucleons (protons and neutrons) to a nucleus, there are certain points where the binding energy of the next nucleon is significantly less than the last one. This observation th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Physical Review
''Physical Review'' is a peer-reviewed scientific journal. The journal was established in 1893 by Edward Nichols. It publishes original research as well as scientific and literature reviews on all aspects of physics. It is published by the American Physical Society (APS). The journal is in its third series, and is split in several sub-journals each covering a particular field of physics. It has a sister journal, '' Physical Review Letters'', which publishes shorter articles of broader interest. History ''Physical Review'' commenced publication in July 1893, organized by Cornell University professor Edward Nichols and helped by the new president of Cornell, J. Gould Schurman. The journal was managed and edited at Cornell in upstate New York from 1893 to 1913 by Nichols, Ernest Merritt, and Frederick Bedell. The 33 volumes published during this time constitute ''Physical Review Series I''. The American Physical Society (APS), founded in 1899, took over its publicati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mandelstam Variables
In theoretical physics, the Mandelstam variables are numerical quantities that encode the energy Energy () is the physical quantity, quantitative physical property, property that is transferred to a physical body, body or to a physical system, recognizable in the performance of Work (thermodynamics), work and in the form of heat and l ..., momentum, and angles of particles in a scattering process in a Lorentz-invariant fashion. They are used for scattering processes of two particles to two particles. The Mandelstam variables were first introduced by physicist Stanley Mandelstam in 1958. If the Minkowski metric is chosen to be \mathrm(1, -1,-1,-1), the Mandelstam variables s,t,u are then defined by :*s=(p_1+p_2)^2 c^2 =(p_3+p_4)^2 c^2 :*t=(p_1-p_3)^2 c^2 =(p_4-p_2)^2 c^2 :*u=(p_1-p_4)^2 c^2 =(p_3-p_2)^2 c^2, where ''p''1 and ''p''2 are the four-momenta of the incoming particles and ''p''3 and ''p''4 are the four-momenta of the outgoing particles. s is also known as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Conformal Field Theory
A conformal field theory (CFT) is a quantum field theory that is invariant under conformal transformations. In two dimensions, there is an infinite-dimensional algebra of local conformal transformations, and conformal field theories can sometimes be exactly solved or classified. Conformal field theory has important applications to condensed matter physics, statistical mechanics, quantum statistical mechanics, and string theory. Statistical and condensed matter systems are indeed often conformally invariant at their thermodynamic or quantum critical points. Scale invariance vs conformal invariance In quantum field theory, scale invariance is a common and natural symmetry, because any fixed point of the renormalization group is by definition scale invariant. Conformal symmetry is stronger than scale invariance, and one needs additional assumptions to argue that it should appear in nature. The basic idea behind its plausibility is that ''local'' scale invariant theories have t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Lettere Al Nuovo Cimento
''Nuovo Cimento'' is a series of peer-reviewed scientific journals of physics. The series was first established in 1855, when Carlo Matteucci and Raffaele Piria started publishing ''Il Nuovo Cimento'' as the continuation of ''Il Cimento'', which they established in 1844. In 1897, it became the official journal of the Italian Physical Society. Over time, the journal split into several sub-journals: * ''Nuovo Cimento A'' (1965–1999): Focused on particle physics. The journal ended when it was merged into the ''European Physical Journal'', in 1999. * ''Nuovo Cimento B'' (1965–2010): Focused on relativity, astronomy, and mathematical physics. As of 1 January 2011 it continues publication as the '' European Physical Journal Plus''. * ''Nuovo Cimento C'' (1978–present): Focuses on geophysics, astrophysics, and biophysics. * ''Nuovo Cimento D'' (1982–1998): Focuses on solid state physics, atomic physics, and molecular biology. The journal ended when it was merged into the ''Euro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
