I am curious about magnets and their interaction with the electromagnetic field.

So I tried to find this answer and stumbled upon (Magnetism and Photons), this is an interesting description that I quite like, but it doesn't really explain how a magnet can keep a piece of metal on a string hovering in mid-air indefinitely, the magnet is not moving, yet there is an interaction there, as I understand it via photon exchange.

I did read in a magazine (New Scientist particle physics special from memory) that electron spins create a non homogeneity that interacts with the electromagnetic field that then "tends" to allow virtual elements to appear through particle/antiparticle annihilation, with a resulting photon being generated. I don't love this explanation, perhaps because I find it hard to get my head around it.

Any advice or references you can point to explain the electromagnetic field (this is confusing in itself, I thought long ago we gave up on the idea of an "ether", it seems it's back) and then the interaction of electron spins (magnetism) on this field.

Thanks in advance, Tibor

  • $\begingroup$ The interpretation of what the EM interaction is doing is most easiest in the Coulomb gauge, where we have familiar electrostatic Coulomb potential, transverse light waves and nothing too weird. In this form, the magnet sets up a purely magnetic field that has no electric field part, and thus cannot be any of the transverse photons. The photon exchange picture is a QED correction and many orders of magnitude much more difficult to understand. You could derive the static Coulomb potential and magnetic fields from scalar and longitudinal photons, but that is a complication of little insight. $\endgroup$ Jul 25, 2023 at 5:23


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