uncertainty principle

American  

noun

Physics.

1. the principle of quantum mechanics, formulated by Heisenberg, that the accurate measurement of one of two related, observable quantities, as position and momentum or energy and time, produces uncertainties in the measurement of the other, such that the product of the uncertainties of both quantities is equal to or greater than h/ 2 π, where h equals Planck's constant.

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uncertainty principle British  

noun

1. Also known as: Heisenberg uncertainty principle.   indeterminacy principle.  the principle that energy and time or position and momentum of a quantum mechanical system, cannot both be accurately measured simultaneously. The product of their uncertainties is always greater than or of the order of h , where h is the Planck constant

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uncertainty principle Scientific  

/ ŭn-sûr′tn-tē /

1. A principle, especially as formulated in quantum mechanics, that greater accuracy of measurement for one observable entails less accuracy of measurement for another. For example, it is in principle impossible to measure both the momentum and the position of a particle at the same time with perfect accuracy. Any pair of observables whose operators do not commute have this property. As defined in quantum mechanics, it is also called Heisenberg's uncertainty principle. Similar uncertainty principles hold for non-quantum mechanical systems involving waves as well.

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uncertainty principle Cultural  

1. The statement in quantum mechanics, formulated by Werner Heisenberg, that it is impossible to measure two properties of a quantum object, such as its position and momentum (or energy and time), simultaneously with infinite precision.

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Etymology

Origin of uncertainty principle

First recorded in 1930–35

Example Sentences

Simon Stephens’ drama, presented at the Mark Taper Forum in 2017, is a two-hander that tests the validity of the uncertainty principle in the arena of human relationships.

From Los Angeles Times • Dec. 17, 2025

To the chagrin of many physicists, the Heisenberg uncertainty principle determines that one cannot simultaneously know a signal's position and momentum, or voltage and current, with accuracy.

From Science Daily • Apr. 10, 2024

All these applications are based on the counterintuitive features of quantum theory, such as superpositions, entanglement and the uncertainty principle, which are also part of real quantum theory.

From Scientific American • Apr. 24, 2023

They pointed out that, according to the uncertainty principle of quantum physics, a pair of particles once associated would be eternally connected, even if they were light-years apart.

From New York Times • Oct. 10, 2022

Thus all the complicated structures that we see in the universe might be explained by the no boundary condition for the universe together with the uncertainty principle of quantum mechanics.

From "A Brief History of Time: And Other Essays" by Stephen Hawking