The vacuum itself does not distinguish frequencies. Only matter can distinguish them because of their structure. But the vacuum vacuum has no structure.

@Paul Dirac argued that a vacuum has a structure!

Dear Preston Guynn, But it is known that light, when propagating in material media, experiences frequency dispersion. A vacuum is an exception in this sense. This difference needs to be explained. Thanks for the reaction. Best wishes!

Dispersion is created primarily by interaction of the radiation with the electrons in matter. If there are no electrons to interact with, not observing any dispersion ist not a surprise.

Dear Jürgen Weippert!

Yes! There are no free electrons in the vacuum, but it is recognized that it has a structure of harmonic oscillators responsible for the so-called zero vacuum oscillations. What about this?

Best wishes!

On web of science, the term "zero vacuum oscillations" has zero search results. On Google Scholar, there are 39 hits to this term, but after clicking on three of them, each of them used it in a different manner.

So it is not a standard term; which definition of it are you referring to?

If you are talking about the v=0 energy of harmonic oscillators: the existence of these still requires something that can vibrate (like atom nuclei).

See:

https://journals.aps.org/pr/abstract/10.1103/PhysRev.74.1157

Best Regards!

In the paper you linked, there is only one occurence of the word vacuum and it is not in the expression "zero vacuum oscillations". Please give us the exact definition of what you want to use here.

The one vacuum term in the paper addresses the concept of "filled negative states" in the sense of the Dirac equation. On more modern concepts in this context, start at https://en.wikipedia.org/wiki/Dirac_sea#Modern_interpretation

Wikipedia is not the best adviser. It is better to read original articles, including on the history of the formation of modern ideas about the vacuum. I also know the concept of vacuum from the works of three Nobel laureates in quantum electrodynamics. But unfortunately, I didn't find the answer to my question there. I am waiting for the response of experts in this field.

Best wishes!

Well, Wikipedia is of course not an original source, rather a nice starter to get ideas what to search for, but you missed my actual point entirely: the article you referenced does not use the expression "zero vacuum oscillations" and therefore also doesn't provide a definition.

As I mentioned above, a very limited set of articles contains this term and they use it in a wildly different sense. Therefore, unless you tell us which definition of this term you are using, there is no hope for you to get a qualified answer.

I have accepted your answer. "There is no frequency dispersion of electromagnetic waves in a vacuum due to the absence of electrons there." He didn't suit me. But I'm grateful for your reaction! The term " vacuum zero fluctuations" is used in the Russian segment. Perhaps the translation of this term into English was unsuccessful?

So thanks and best wishes!

Well, why don't you just write down a definition of what this term means within your framework? Maybe we can figure out what the "standard English term" for the physical phenomenon is and thus get to a more satisfying result.

Perhaps the correct answer to this question is here: https://www.researchgate.net/publication/393418309_ON_THE_POSSIBILITY_AND_CAUSES_OF_ABNORMAL_FREQUENCY_DISPERSION_OF_ELECTROMAGNETIC_RADIATION_IN_VACUUM