a theory of the mechanics of atoms, molecules, and other physical systems that are subject to the uncertainty principle. Abbreviation: QM
Origin of quantum mechanics
First recorded in 1920–25Related formsquan·tum-me·chan·i·cal, adjective
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for quantum mechanics
(functioning as singular) the branch of mechanics, based on the quantum theory used for interpreting the behaviour of elementary particles and atoms, which do not obey Newtonian mechanics
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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quantum mechanics in Science
A fundamental theory of matter and energy that explains facts that previous physical theories were unable to account for, in particular the fact that energy is absorbed and released in small, discrete quantities (quanta), and that all matter displays both wavelike and particlelike properties, especially when viewed at atomic and subatomic scales. Quantum mechanics suggests that the behavior of matter and energy is inherently probabilistic and that the effect of the observer on the physical system being observed must be understood as a part of that system. Also called quantum physics quantum theory Compare classical physics. See also probability wave quantum uncertainty principle wave-particle duality.
The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
quantum mechanics in Culture
The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.