Casimir effect

American  

[kaz-uh-meer-i-fekt] / ˈkæz əˌmɪər ɪˌfɛkt /

noun

1. the effect produced by an attractive force (Casimir force) between objects in close proximity to each other, caused by a disparity in quantum vacuum fluctuations.

---

Casimir effect Scientific  

/ kăz′ə-mîr′ /

1. The effect of a net attractive force between objects in a vacuum, caused by quantum mechanical vacuum fluctuations creating radiation pressure. The radiation can be thought of as an atmosphere of virtual particles. The amount of radiation pressure on the objects is decreased in the gap between them, due to limits on the wavelength of the radiation in the gap. The gap is thus an area of lower radiation pressure, drawing the objects toward it. This force is strong enough to be of great importance at scales encountered in nanotechnology. The Casimir effect is named after Dutch physicist Hendrik Casimir (1909–2000).

---

Example Sentences

The attractive force, known as the Casimir effect, causes the gold flakes to draw closer together and toward the substrate.

From Science Daily • Oct. 23, 2025

To date, no one has proved that the Casimir effect works in high-temperature superconductors, but the scientists are betting that it does.

From Scientific American • Apr. 29, 2023

Despite the team's careful planning, the measurement will be quite challenging, says Lamoreaux, who first demonstrated the Casimir effect.

From Scientific American • Apr. 29, 2023

In planning the experiment, the scientists needed to find a suitable material that could be heated and cooled uniformly and quickly and that exhibited a strong Casimir effect.

From Scientific American • Apr. 29, 2023

In theory, scientists can get energy from the Casimir effect even at absolute zero in the bleakest part of the vacuum of space.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife