Most textbooks explain the Casimir force by using the infinitely large ground state energy associated with quantum fields. Since the total energy between two conducting plates is different from the total outside of the plates, there is a net energy difference and thus a force acting on them. This force is known as Casimir force and was observed in experiments. The effect therefore seems to confirm that the ground state energy of quantum fields is nonzero and leads to measurable effects.
On the other hand, it's sometimes argued that the Casimir force "is just the van der Waals force derived in a different language." In particular:
Conceptually, saying that "the plates force the electric field to vanish" is the same as saying "electronic fluctuations in the two plates become synchronized", which is how we describe the origin of the van der Waals force.
Moreover, this highly cited paper concludes that
Still, no known phenomenon, including the Casimir effect, demonstrates that zero point energies are “real”.
What's the exact relationship between the two explanations? Is one of them wrong or is the standard derivation in terms of ground state energies really just a derivation of the van der Waals force in disguise?
