| THE CASIMIR EFFECT | ||
| “Nihil ex nihilo fit”: This is a well-known motto dating back to Melisso (a disciple of Parmenides and Lucretius), taken among others from Shakespeare, who puts in the mouth to the old King Lear. “Nothing can come from nothing”… Or at least it was so until the birth of quantum physics (and in particular, quantum electrodynamics). The vision of nature asserted itself in the last century provides that the VOID (the "nihil", classical in the sense of non-quantum) is a noun that is not appropriate to itself in the form of an adjective. Quantum electrodynamics, in fact, has taught us that: |
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The Vacuum is not empty! |
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Quantum physics states, in fact, that it is full of particle/antiparticle pairs, whose life is very ephemeral; the more ephemeral the higher their energy. In particular, “vacuum” is swarming with "virtual” photons: these are the fluctuations of the electromagnetic field, whose existence is imposed by the Heisenberg uncertainty principle. This physical law, in fact, prohibits - among others - that the electric and magnetic fields can be measured simultaneously with arbitrary precision: hence they cannot be simultaneously zero, then the "vacuum" cannot be completely free of electromagnetic fields. |
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| These incessant vacuum fluctuations cannot be directly observed, nevertheless they have many experimentally observable consequences; among them the Casimir effect. | ||