Casimirefekti

Casimirefekti (Casimir effect) is a quantum phenomenon in which vacuum fluctuations of the electromagnetic field produce an observable force between neutral conducting boundaries. It was predicted by Dutch physicist Hendrik B. G. Casimir in 1948.

In the idealized setup of two parallel, perfectly conducting plates in vacuum separated by distance a, the allowed vacuum modes lead to a net attractive force per unit area F/A = - π^2 ħ c / (240 a^4). The effect arises from boundary conditions that modify the zero-point energy of the electromagnetic field. Real-world calculations often use Lifshitz theory to account for material properties, temperature, and geometry.

Direct measurements were first reported by Lamoreaux in 1997 using a torsion pendulum, and by Mohideen and Roy in 1998 with an atomic force microscope. Subsequent experiments with microcantilevers and torsional oscillators have confirmed the Casimir force with increasing precision, within experimental uncertainties. Finite conductivity, surface roughness, and finite temperature introduce corrections that theory continues to refine.

Casimirefekti extends beyond plate–plate geometries and relates to the Casimir–Polder force between neutral atoms and surfaces. Generalizations include different geometries and materials, as well as temperature-dependent forms of the force. The effect is of practical interest in nanotechnology, where Casimir forces can influence the operation of micro- and nanoelectromechanical systems (MEMS/NEMS) and pose design considerations for stiction and actuation.

See also: Lifshitz theory; Casimir–Polder force; quantum vacuum.