# Fine-Structure Constant

(redirected from Fine structure constant)

## fine-structure constant

[′fīn ‚strək·chər ′kän·stənt]
(physics)
A fundamental dimensionless constant, equal to e 2/(4πε0c) in International System (SI) units and to e 2/(ℏ c) in centimeter-gram-second (cgs) electrostatic units, where e is the elementary charge, ℏ is Planck's constant divided by 2π, c is the speed of light, and ε0 is the electric constant; numerically, it is equal to 0.007 297 352 533 ± 0.000 000 000 027 or to 1/(137.035 999 76 ± 0.000 000 50); symbolized α. Also known as Sommerfeld fine-structure constant.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

## Fine-Structure Constant

(α), a dimensionless quantity formed from universal physical constants: α = e2/hc ≠ 1/137, where e is the elementary electric charge, h is Planck’s constant, and c is the speed of light in a vacuum. According to the most accurate measurements, which are based on the Josephson effect, α–1 = 137.0359 ± 0.0004. The constant α is called the fine-structure constant because it determines the fine structure of the energy levels of an atom in the sense that the magnitude of the fine-structure splitting is proportional to α2. In quantum electrodynamics, α is a natural parameter that characterizes the strength of the electromagnetic interaction.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The fine structure constant is given by the ratio [alpha] = [e.sup.2]/[e.sup.2.sub.*], where (-e) is the observed electronic charge.
The terms [[DELTA].sup.i.sub.I], i = U, [kappa], [[alpha].sub.G], denote the threshold corrections due to unification scale ([M.sub.U]), intermediate scale ([M.sub.[kappa]]), and GUT fine structure constant (1/[[alpha].sub.G]).
I will present 4 cosmological signatures produced by such a coupling: a violation of the cosmic distance-duality relation, a temporal variation of the fine structure constant, a modification of the evolution of the CMB temperature and CMB spectral distortions.
The fine structure constant, also known as alpha, has been both essential and confounding to physicists.
Ultra-precise atomic clocks can be used to verify Einstein's general theory of relativity as well as test whether constants of nature change over time, for example, the fine structure constant, which describes the size of the electron energies of the atomic structure.
But the new study focuses on the fine structure constant, also known as alpha.
It is known that since the fine structure constant relates the three fundamental constants of c, e and h, not all of the latter can be fundamental at the same time.
He also discovered that the beta ratio is not only "the ratio between the magnitude of the mass of the proton over that of the electron" but also "the ratio between the magnitudes of all the other corresponding quantum attributes of the electron and proton." He found that the probable definition of the fine structure constant is the ratio between the magnitudes of local inertia and the universal minimum and that this reveals the meaning of the mystery number 137.
where [m.sub.p] is the proton mass, [alpha] is the fine structure constant, [e.sub.V.sup.R] is a low energy constant, [[partial derivative].sub.a]'s are model-independent radiative corrections, [[~.g].sub.A] is the axial coupling constant, and the correlation coefficients a, A, B are incorporated into the recoil corrections [C.sub.i]([E.sub.e]) .
The threat to the idea of an invariable speed of light comes from measurements of another parameter called the fine structure constant, or alpha, which dictates the strength of the electromagnetic force.
Cahill  introduced an additional dimensionless constant that coincides with the fine structure constant and determines the strength of a new 3-space self-interaction that can explain various gravitational anomalies, such as the 'borehole anomaly' and the 'dark matter anomaly' in the rotation speeds of spiral galaxies.

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