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Casimir effect
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Attractive force between plates from vacuum fluctuations.
Two uncharged metal plates close together attract because they restrict vacuum electromagnetic modes between them: F/A = −π²ħc/(240d⁴).
At 100 nm: about 1 atm pressure.
Evidence for vacuum fluctuations.
In more detail
The Casimir effect is an attractive force between uncharged conducting plates, arising from changes in the zero-point energy of the electromagnetic field between them.
Real-world uses
- The Casimir effect has been measured in micro-electromechanical devices.
- It is studied in theories of vacuum energy.
- Physicists study the Casimir effect to understand how vacuum fluctuations produce measurable forces between close plates.
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Frequently asked questions
Is the Casimir force strong?
It is weak in everyday terms but becomes significant at very small separations.
Does it prove vacuum energy?
It is evidence for zero-point fluctuations, which are part of quantum field theory.
Is the Casimir force real?
Yes. It has been measured in laboratory experiments between closely spaced metal surfaces.
Related topics in Quantum Mechanics
Quantum field theory intro · Feynman path integral · Quantum electrodynamics · Quantum Hall effect · Superfluidity · Superconductivity and BCS theory