Does Matter Expel the Quantum Vacuum? The Casimir effect is demonstrated by measuring forces between two bodies, the first being between very narrowly spaced parallel plates.  A net force occurs that is attributable to the properties of the quantum vacuum.  Does this mean that the space occupied by the parallel plates is void of these properties?
Note: "As I understand it" should preface most of the sentences above.
I could have been more clear.  What I meant to ask is if the quantum vacuum fluctuations are within the plates - does the quantum vacuum occur within the solid?
24 Feb 2022 I'm still not clear on the answer, so I'll re-phrase the explanation of the title question.  Ignoring the description of the experiment, are there the same quantum vacuum fluctuations within a solid block of steel as in the vacuum of space?  So, in experiments to measure the Casimir effects, are there vacuum quantum effects expected from inside the surfaces of the bounding materials?  To re-phrase, are there quantum vacuum effects inside a solid body, like a solid block of steel?
 A: "Although the particles are not directly detectable, the cumulative effects of these particles are measurable. For example, without quantum fluctuations, the "bare" mass and charge of elementary particles would be infinite; from renormalization theory the shielding effect of the cloud of virtual particles is responsible for the finite mass and charge of elementary particles. Another consequence is the Casimir effect. "
Wiki says yes.
I think i've also heard an explanation through lack of photons between plates, and presence of those photons on the outside of plates, not sure how right is it.
And here it says that theory lags behind our experiments, and we dont know yet how to explain it well, and several explanations are possible.
You may be also interested in interaction of quantum fluctuations and quarks and gluons. Casimir effect is rather weak.
A: No, this is not what it means. There is vacuum on both the inside and outside of the plates and there are quantum fluctuations in both the regions as well.
The reason why the region in between the plates is significant is because of the distance between them.
There are fluctuating electromagnetic waves in both regions due to particle-antiparticle creation/annihilation. These electromagnetic waves have a wavelength of course, and if the plates are a sufficient distance apart, then electromagnetic waves (striking the plates) of any wavelength will be permitted in between the plates. Now suppose you move the plates close enough together so that these wavelengths will no longer fit. The result is that the EM waves outside the plates will exert a greater pressure than those inside. So there will be a greater force outside the plates than inside, hence the plates will be "attracted" toward each other.
