quantum mechanics

noun

Physics.

1. a theory of the mechanics of atoms, molecules, and other physical systems that are subject to the uncertainty principle. QM

quantum mechanics

noun

1. (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

quantum mechanics

1. 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.

2. Also called quantum physics quantum theory

3. Compare classical physics See also probability wave quantum uncertainty principle wave-particle duality

quantum mechanics

1. The branch of physics that deals with the behavior of matter at the level of the atom, the nucleus, and the elementary particle. At this level, energy, mass, momentum, and other quantities do not vary continuously, as they do in the large-scale world, but come in discrete units, or quanta. (See Bohr atom and photon.)

Other Word Forms

• quantum-mechanical adjective

Word History and Origins

Origin of quantum mechanics¹

First recorded in 1920–25

Example Sentences

The meaning of life, the laws of general relativity, quantum mechanics, Fermat's last theorem.

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This week, the Nobel Prize in Physics was awarded to a trio of scientists focused on quantum mechanics.

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"There is no advanced technology used today that does not rely on quantum mechanics, including mobile phones, cameras... and fibre optic cables," said the Nobel committee.

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Wheeler’s idea of the participatory universe is rooted in quantum mechanics, which allows a particle to be in two places at once by being in what is called a superposition state.

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She is proud that Ghana, backed by Mexico, spearheaded proposals that 2025 be declared the UN International Year of Quantum Science and Technology - on the 100th anniversary of the discovery of modern quantum mechanics.

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