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List Of Things Named After Enrico Fermi
Enrico Fermi (1901–1954), an Italian-born, naturalized American physicist, is the eponym of the topics listed below. Physics *Fermi (unit), unit of length in particle physics equivalent to the femtometre *Fermi arc, a phenomenon in superconductivity *Fermi constant, constant that gives the strength of Fermi's interaction *Fermi contact interaction, the magnetic interaction between an electron and an atomic nucleus when the electron is inside that nucleus *Fermi energy * Fermi's four factor formula *Fermi gas *Fermi's interaction, an explanation of the beta decay *Fermi level *Fermi liquid theory ** Quasi Fermi level, also called imref which is "fermi" spelt backwards * Fermi heap and Fermi hole *Fermi paradox, a fundamental issue in SETI * Fermi point * Fermi pseudopotential *Fermi's golden rule *Fermi motion, the quantum motion of nucleons bound inside a nucleus * Fermi resonance *Fermi surface *Fermi acceleration **Fermi–Ulam model ** Fermi–Pustyl'nikov model, a model o ... [...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] |
Fermi's Golden Rule
In quantum physics, Fermi's golden rule is a formula that describes the transition rate (the probability of a transition per unit time) from one energy eigenstate of a quantum system to a group of energy eigenstates in a continuum, as a result of a weak perturbation. This transition rate is effectively independent of time (so long as the strength of the perturbation is independent of time) and is proportional to the strength of the coupling between the initial and final states of the system (described by the square of the matrix element of the perturbation) as well as the density of states. It is also applicable when the final state is discrete, i.e. it is not part of a continuum, if there is some decoherence in the process, like relaxation or collision of the atoms, or like noise in the perturbation, in which case the density of states is replaced by the reciprocal of the decoherence bandwidth. General Although the rule is named after Enrico Fermi, most of the work leading to it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fermionic Condensate
A fermionic condensate or Fermi–Dirac condensate is a superfluid phase formed by fermionic particles at low temperatures. It is closely related to the Bose–Einstein condensate, a superfluid phase formed by bosonic atoms under similar conditions. The earliest recognized fermionic condensate described the state of electrons in a superconductor; the physics of other examples including recent work with fermionic atoms is analogous. The first atomic fermionic condensate was created by a team led by Deborah S. Jin using potassium-40 atoms at the University of Colorado Boulder in 2003. Background Superfluidity Fermionic condensates are attained at lower temperatures than Bose–Einstein condensates. Fermionic condensates are a type of superfluid. As the name suggests, a superfluid possesses fluid properties similar to those possessed by ordinary liquids and gases, such as the lack of a definite shape and the ability to flow in response to applied forces. However, superfluids pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fermi–Dirac Statistics
Fermi–Dirac statistics (F–D statistics) is a type of quantum statistics that applies to the physics of a system consisting of many non-interacting, identical particles that obey the Pauli exclusion principle. A result is the Fermi–Dirac distribution of particles over energy states. It is named after Enrico Fermi and Paul Dirac, each of whom derived the distribution independently in 1926 (although Fermi derived it before Dirac). Fermi–Dirac statistics is a part of the field of statistical mechanics and uses the principles of quantum mechanics. F–D statistics applies to identical and indistinguishable particles with half-integer spin (1/2, 3/2, etc.), called fermions, in thermodynamic equilibrium. For the case of negligible interaction between particles, the system can be described in terms of single-particle energy states. A result is the F–D distribution of particles over these states where no two particles can occupy the same state, which has a considerable effec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fermi–Walker Transport
Fermi–Walker transport is a process in general relativity used to define a coordinate system or reference frame such that all curvature in the frame is due to the presence of mass/energy density and not to arbitrary spin or rotation of the frame. Fermi–Walker differentiation In the theory of Lorentzian manifolds, Fermi–Walker differentiation is a generalization of covariant differentiation. In general relativity, Fermi–Walker derivatives of the spacelike vector fields in a frame field, taken with respect to the timelike unit vector field in the frame field, are used to define non-inertial and non-rotating frames, by stipulating that the Fermi–Walker derivatives should vanish. In the special case of inertial frames, the Fermi–Walker derivatives reduce to covariant derivatives. With a (-+++) sign convention, this is defined for a vector field ''X'' along a curve \gamma(s): :\frac=\frac - \left(X,\frac\right) V + (X,V)\frac, where is four-velocity, is the covariant der ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Decay Transition
In nuclear physics, a beta decay transition is the change in state of an atomic nucleus undergoing beta decay. (β-decay) When undergoing beta decay, a nucleus emits a beta particle and a corresponding neutrino, transforming the original nuclide into one with the same mass, but differing charge. (an isobar) There are several types of beta decay transition. In a ''Fermi transition'', the spins of the two emitted particles are anti-parallel, for a combined spin S=0. As a result, the total angular momentum of the nucleus is unchanged by the transition. By contrast, in a ''Gamow-Teller'' transition, the spins of the two emitted particles are parallel, with total spin S=1, leading to a change in angular momentum between the initial and final states of the nucleus. The theoretical work in describing these transitions was done between 1934 and 1936 by George Gamow and Edward Teller at George Washington University. The weak interaction and beta decay β decay had been first describe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Composite Fermion
A composite fermion is the topological bound state of an electron and an even number of quantized vortices, sometimes visually pictured as the bound state of an electron and, attached, an even number of magnetic flux quanta. Composite fermions were originally envisioned in the context of the fractional quantum Hall effect, but subsequently took on a life of their own, exhibiting many other consequences and phenomena. Vortices are an example of topological defect, and also occur in other situations. Quantized vortices are found in type II superconductors, called Abrikosov vortices. Classical vortices are relevant to the Berezenskii–Kosterlitz–Thouless transition in two-dimensional XY model. Description When electrons are confined to two dimensions, cooled to very low temperatures, and subjected to a strong magnetic field, their kinetic energy is quenched due to Landau level quantization. Their behavior under such conditions is governed by the Coulomb repulsion alone, and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fermi Ball
In cosmology, Fermi balls are hypothetical objects that may have been created in the early history of the universe by spontaneous symmetry breaking. One paper has described them as "charged SLAC-bag type structures". Fermi balls can be modeled as a type of non-topological soliton. The concept is named after Enrico Fermi (see Fermion). Hypothesized explanations for observed phenomena Dark matter A paper by theoretical physicists at Seoul National University has proposed that Fermi balls may be implicated in the formation of primordial black holes from a cosmic first-order phase transition, as a candidate explanation for dark matter Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not ab .... References Physical cosmology Hypothetical astronomical objects {{physical-cosmology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fermi Glow
The Fermi glow consists of ultraviolet-glowing particles, mostly hydrogen, originating from the Solar System's bow shock, created when light from stars and the Sun enter the region between the heliopause and the interstellar mediumA Glowing Discovery at the Forefront of Our Plunge Through Space ". . 15 March 2000. and undergo , bouncing around the transition area several times, gaining energy via collisions with atoms of the interstellar medium. The first evidence of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fermi–Pustyl'nikov Model
The Fermi–Pustyl'nikov model, named after Enrico Fermi and Lev Pustyl'nikov, is a model of the Fermi acceleration mechanism. A point mass falls with a constant acceleration vertically on the infinitely heavy horizontal wall, which moves vertically in accordance with analytic periodic law in time. The point interacts with the wall by the law of elastic collision. For this model it was proved that under some general conditions the velocity and energy of the point at the moments of collisions with the wall tend to infinity for an open set of initial data having the infinite Lebesgue measure In measure theory, a branch of mathematics, the Lebesgue measure, named after French mathematician Henri Lebesgue, is the standard way of assigning a measure to subsets of ''n''-dimensional Euclidean space. For ''n'' = 1, 2, or 3, it coincides wit ....L. D. Pustyl'nikov (1977), Stable and oscillating motions in nonatonomous dynamical systems II. (Russian) Trudy Moscow. Mat. Obsc. 34, 3–103. E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fermi–Ulam Model
The Fermi–Ulam model (FUM) is a dynamical system that was introduced by Poland, Polish mathematician Stanislaw Ulam in 1961. FUM is a variant of Enrico Fermi's primary work on acceleration of cosmic rays, namely Fermi acceleration. The system consists of a particle that elastic collision, collides elastically between a fixed wall and a moving one, each of infinite mass. The walls represent the magnetic mirrors with which the cosmic rays, cosmic particles collide. A. J. Lichtenberg and M. A. Lieberman provided a simplified version of FUM (SFUM) that derives from the Poincaré map, Poincaré surface of section x=const. and writes : u_=, u_n+U_\mathrm(\varphi_n), : \varphi_=\varphi_n+\frac \pmod k, where u_n is the velocity of the particle after the n-th collision with the fixed wall, \varphi_n is the corresponding phase of the moving wall, U_\mathrm is the velocity law of the moving wall and M is the stochasticity parameter of the system. If the velocity law of the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fermi Acceleration
Fermi acceleration, sometimes referred to as ''diffusive shock acceleration'' (a subclass of Fermi accelerationOn the Origin of the Cosmic Radiation, E. Fermi, Physical Review 75, pp. 1169-1174, 1949), is the acceleration that charged particles undergo when being repeatedly reflected, usually by a magnetic mirror (see also Centrifugal mechanism of acceleration). It receives its name from physicist Enrico Fermi who first proposed the mechanism. This is thought to be the primary mechanism by which particles gain non-thermal energies in astrophysical shock waves. It plays a very important role in many astrophysical models, mainly of shocks including solar flares and supernova remnants. There are two types of Fermi acceleration: first-order Fermi acceleration (in shocks) and second-order Fermi acceleration (in the environment of moving magnetized gas clouds). In both cases the environment has to be collisionless in order for the mechanism to be effective. This is because Fermi accelera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
