THE CASIMIR EFFECT

The Casimir effect is usually interpreted as due to the modification of the zero point energy of QED when two perfectly conducting plates are put very close to each other, and as a proof of the "reality" of this zero point energy. The Dark Energy, necessary to explain the acceleration of the expansion of the Universe is sometimes viewed as another proof of the same reality. The usual interpretation of the Casimir effect is however challenged by some authors who rather consider it as a "giant" van der Waals effect. All these aspects are shortly reviewed.