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exclusion principle

(Encyclopedia)exclusion principle, physical principle enunciated by Wolfgang Pauli in 1925 stating that no two electrons in an atom can occupy the same energy state simultaneously. The energy states, or levels, in ...

Von Neumann, John

(Encyclopedia)Von Neumann, John noiˈmän [key], 1903–57, American mathematician, b. Hungary, Ph.D. Univ. of Budapest, 1926. He came to the United States in 1930 and was naturalized in 1937. He taught (1930–33)...

Broglie, Louis Victor, duc de

(Encyclopedia)Broglie, Louis Victor, duc de, 1892–1987, French physicist. In 1928 he became professor in the faculty of sciences, Univ. of Paris. It was known from the earlier quantum theory that light waves some...

molecular orbital theory

(Encyclopedia)molecular orbital theory, detailed explanation of how electrons are distributed in stable molecules. In the simpler valence theory of the chemical bond, each atom in a molecule is assumed to retain it...

games, theory of

(Encyclopedia)games, theory of, group of mathematical theories first developed by John Von Neumann and Oskar Morgenstern. A game consists of a set of rules governing a competitive situation in which from two to n i...

steady-state theory

(Encyclopedia)steady-state theory: see cosmology. ...

Young-Helmholtz theory

(Encyclopedia)Young-Helmholtz theory: see vision. ...

big-bang theory

(Encyclopedia)big-bang theory: see cosmology.

electrodynamics

(Encyclopedia)electrodynamics, study of phenomena associated with charged bodies in motion and varying electric and magnetic fields (see charge; electricity); since a moving charge produces a magnetic field, electr...

superfluidity

(Encyclopedia)superfluidity, tendency of liquid helium below a temperature of 2.19K to flow freely, even upward, with little apparent friction. Helium becomes a liquid when it is cooled to 4.2K. Special methods...