virtual particle

American  

noun

Physics.

1. an elementary particle of transitory existence that does not appear as a free particle in a particular situation but that can transmit a force from one particle to another.

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virtual particle Scientific  

1. A short-lived subatomic particle whose existence briefly violates the principle of conservation of energy. The uncertainty principle of quantum mechanics allows violations of conservation of energy for short periods, meaning that even a physical system with zero energy can spontaneously produce energetic particles. The more energy a virtual particle has, the shorter its existence. Interactions between normal particles and virtual particles play a crucial role in quantum field theory analyses of interactions between real particles.

2. See also Casimir effect Feynman diagram vacuum fluctuation

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Etymology

Origin of virtual particle

First recorded in 1970–75

Example Sentences

This mind-blowing feature of the quantum world plays a crucial role in particle physics experiments; indeed, the discovery of the Higgs boson was enabled by virtual particle effects at the LHC.

From Scientific American • Sep. 14, 2021

It is not directly observable and is called a virtual particle.

From Textbooks • Aug. 12, 2015

The Hawking radiation is the result of virtual particle pairs popping into existence near the event horizon, with one partner falling in and the other escaping.

From Scientific American • Dec. 21, 2012

Image: Courtesy of Joseph Polchinski This radiation results from virtual particle pairs popping out of the quantum vacuum near a black hole.

From Scientific American • Dec. 21, 2012

The one with negative energy is condemned to be a short-lived virtual particle because real particles always have positive energy in normal situations.

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