# The energy carried from one winding of a transformer to another, in quantum terms

I have read in wikipedia this statement

"The energy carried from one winding of a transformer to another, in quantum terms is carried by virtual photons, not real photons" (wikipedia src: virtual particle)

Of course anything in wikipedia could be solved "changing it" =), but I wonder, someone put it for a reason, then in the case it have sense, I don't know what is the limit for that, what are the frequencies for virtual or real photon interactions. (if is the frequency what makes the difference, or what ?)

Perhaps it's related with the kind of interaction, I mean photoelectric effect and the induction are different mechanism , but I don't see clearly how "real photons" disappear from the picture, if they are the lesser energy that can be transfered anyway.

I have put that into a comment for this answer Low frequency electromagnetic waves but I think is better to open an specific question.

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There is no quantum terms for the near field. It is not quantized. It exists, as I said, as a potential interaction $\propto \frac{1}{|\vec{r}_1 - \vec{r}_2|}$.
Yes, there is radiationless mechanism of energy exchange. If you scatter one cold atom from another, they may push each other away without any photons, so no $\hbar\omega$ is involved. –  Vladimir Kalitvianski Sep 9 '11 at 16:06