Casimireffect

The Casimir effect, sometimes written as Casimireffect, is a physical manifestation of quantum vacuum fluctuations of the electromagnetic field between closely spaced boundaries. Predicted by Dutch physicist Hendrik B. G. Casimir in 1948, it arises from the modification of zero-point energy of the electromagnetic modes due to imposed boundary conditions, producing a measurable force between neutral bodies in vacuum.

In the idealized case of two perfectly conducting parallel plates of area A separated by distance d, the Casimir force is F = - (π^2 ħ c A)/(240 d^4), or per unit area F/A = - (π^2 ħ c)/(240 d^4). The force is attractive and becomes stronger as the separation decreases. Real-world situations involve finite conductivity, temperature, and more complex geometries, which modify the prediction. Lifshitz theory extends the calculation to dielectric materials and includes thermal corrections, while numerical methods address arbitrary shapes.

Beyond parallel plates, the Casimir effect depends on geometry and material properties, and remains a focus of theoretical and experimental study. Related phenomena include the Casimir–Polder force between neutral atoms and surfaces, and the dynamical Casimir effect, where changing boundary conditions in time can generate real photons from the vacuum.

Experimental confirmations since the late 1990s—using torsion balances, microcantilevers, and atomic-force probes—have demonstrated the existence of the Casimir force and generally agree with theoretical models within uncertainties. The effect has implications for nanotechnology, especially in micro- and nanoelectromechanical systems (MEMS and NEMS), where Casimir forces can influence device operation and stability.