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Related to fermion: boson, quark


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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a particle with half-integral spin or an elementary excitation of a quantum system consisting of many particles, that is, a quasiparticle with half-integral spin. Fermions include all baryons—such as the proton, the neutron, and hyperons—and all leptons—the electron, the muon, and neutrinos—and the anti-particles of all baryons and leptons, as well as such quasiparticles as conduction electrons and holes in a solid. Bound systems consisting of an odd number of fermions are also fermions; examples of such systems are atomic nuclei with an odd atomic number and atoms with an odd difference between the atomic number and the number of electrons. The Pauli exclusion principle is valid for fermions. Consequently, systems consisting of identical fermions obey Fermi-Dirac statistics.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


(quantum mechanics)
A particle, such as the electron, proton, or neutron, which obeys the rule that the wave function of several identical particles changes sign when the coordinates of any pair are interchanged; it therefore obeys the Pauli exclusion principle.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

quantum state

A fundamental attribute of particles according to quantum mechanics. The quantum states are primarily x-y-z position, momentum, angular momentum, energy, spin and time.

The shell structures of the atom are made up of fermion particles, which include the protons and neutrons in the nucleus and the electrons in the outer orbits. Fermions cannot share the same quantum state variables. For example, every electron traveling in electric current has a different quantum state than the electron next to it. The fermion was named after Italian physicist Enrico Fermi (1901-1954).

Bosons are particles that can be in the same quantum state. Photons are examples of bosons, and lasers, masers and the superfluidity Helium derive their behavior as a result. The boson, pronounced "bow-son," was named after Indian physicist Satyendra Nath Bose (1894-1974). See quantum mechanics, electron, photon and Higgs boson.
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References in periodicals archive ?
Rockenbauer's brilliant paper on the extended dirac equation for elementary fermions is a great contribution in the sphere of physics.
Time crystals and quasiparticles called Majorana fermions have made headlines in recent years thanks to the fact they're both so incredibly weird.
Elementary quantum particles are classified into bosons and fermions based on integral and half-integral multiples of [??] respectively, where [??] is Planck's reduced constant.
The functional-integral formulation of the Hubbard model requires the representation of the Hubbard interaction [mathematical expression not reproducible] in terms of squares of fermion operators.
Since v is nonzero, the Hamilton-Jacobi equation satisfied by the classical action I for a fermion finally becomes
In two dimensions, the spectral flow operator that induces the spinor-vector duality and the twist operators which acts on the internal coordinates can be seen to share a common structure in that both have four periodic right-moving fermions. One may further envision that, under decompactification back to 4 dimensions, the two spinor-vector dual vacua appear on the boundaries of the moduli space.
The rhs of expression (16a) can be explicitly written as [DELTA]U - T[DELTA]S, where [DELTA]U = U(T, V, N + 1) - U(T,V,N) and [DELTA]S = S(T, V, N + 1) - S(T, V, N) are the internal energy change of the system and the heat produced T[DELTA]S when adding, isothermally, exactly one more fermion (expression (16a) arises from the forward difference discretization of the conventional definition (15).
The behavior of Weyl fermions makes tantalum arsenide a metal-like compound that shares desirable features with graphene and topological insulators, materials that have attracted a torrent of research attention over the last decade or so.
While the pentaquark can help us understand what makes up matter, the Weyl fermion could increase speed and efficiency in computing power.
Washington, June 23 ( ANI ): Scientists have discovered evidence for the first time, which suggests direct decay of Higgs boson into fermions.
In the high-temperature limit, a(m[beta]) and b(m[beta]) are vanishingly small and the total fermion contribution comes from c(m[beta]) [right arrow] -[[pi].sup.2]/12, yielding