quantum mechanics

American  

noun

Physics.

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

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quantum mechanics British  

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

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quantum mechanics Scientific  

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

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quantum mechanics Cultural  

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.)

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Other Word Forms

• quantum-mechanical adjective

Etymology

Origin of quantum mechanics

First recorded in 1920–25

Example Sentences

"The concept of time has troubled philosophers and physicists for thousands of years, and the advent of quantum mechanics has not simplified the problem," says Professor Hugo Dil, a physicist at EPFL.

From Science Daily

"There has to be some way to resolve this paradox to make our theory of gravity consistent with our theory of quantum mechanics," Mitman said.

From Science Daily

Meanwhile, quantum processors harness the properties of quantum mechanics, which makes them best suited for complex modeling tasks.

From Barron's

Over the past several years, advances in quantum mechanics have allowed researchers to shrink heat engines to microscopic dimensions.

From Science Daily

While this result surprises some physicists, others see it as a natural outcome of one of the most basic principles of quantum mechanics known as unitarity.

From Science Daily