Can light be deflected in an electric field

[ZapperZ]

According to classical electrodynamics you are right.
According to QED you are wrong.
"According to reality" I think you are wrong, but actually I'm not sure if light scattering by a magnetic field has ever been observed. However, what I'm sure of is that light scattering by an electric field from a nucleus, that is Delbrück scattering, has been observed. And that's why I have no doubts in that light can be scattered by a magnetic field too.

But you'll notice that we're not even up to THAT level here. QED predicts this as a higher order interactions. QED also predicts photon-photon scattering. Both of these have NOT been observed and verified experimentally.

Moreoever, if you have followed this thread, we are STUCK in classical E&M and haven't made any progress in establishing even THAT! I certainly am not in the mood to bring in QED when it is not clear that the parties in question don't even know classical E&M.

Zz.

 

[EL]

But you'll notice that we're not even up to THAT level here. QED predicts this as a higher order interactions. QED also predicts photon-photon scattering. Both of these have NOT been observed and verified experimentally.
Moreoever, if you have followed this thread, we are STUCK in classical E&M and haven't made any progress in establishing even THAT! I certainly am not in the mood to bring in QED when it is not clear that the parties in question don't even know classical E&M.
Zz.

Sure. And that's why I stressed you are correct according to classical theory. However, it may be that some others have heard about light scattering by an electromagnetic field, and took it for a classical effect, and then it might be good for those to be told it isn't like that.

 

[EL]

QED predicts this as a higher order interactions. QED also predicts photon-photon scattering. Both of these have NOT been observed and verified experimentally.

Ok, but we can agree on it has been verified for electric fields right? Don't you think that's enough evidence for also regarding photon-magnetic field scattering and photon-photon scattering as verified?
(So I have heard diverging opinions about this: Some think that Delbrück scattering is "enough" of evidence, however I would be glad to hear if you don't agree with them (mainly because I've been doing some work on photon-photon scattering detection myself... ).)

 

[ZapperZ]

I interpret (and so did everyone else who responded) the OP of this thread as a question on classical E&M (light having E and B field components). It would have sounded different had it been on QED.

And I don't know if it has been verified for E fields. Unless I understood QED wrongly, you will only see appreciable effects for gamma photons. This is also true for any possible "photon collider", which is more often called "gamma-gamma collider". I WISH such things have been verified because it would shut up all of those people who claim there's no "photons".

Zz.

 

[jtbell]

So are you saying that Faraday was wrong and that the polarization of light won't be rotated by a strong magnetic field?

Show me the physics that Faraday is describing. And then show me the EXPERIMENTAL VERIFICATION of such an effect.
Zz.

Pinestone, note that Faraday rotation takes place when light passes through a medium that is subjected to a magnetic field. It does not (as far as I can tell) occur when light travels through a vacuum. Faraday rotation is caused by the magnetic field's effect on the medium, not on the light itself.

 

[EL]

I interpret (and so did everyone else who responded) the OP of this thread as a question on classical E&M (light having E and B field components). It would have sounded different had it been on QED. And I don't know if it has been verified for E fields.

Ok. I interpreted it as a question about what can happen in reality, and in reality scattering of photons by an electric field (Delbrück scattering) has been verified! (Don't have the reference right now though.)
But I want to stress that the cross section for this process is extremely tiny, and it has nothing to do with this Faraday rotation which only occurs in a medium.
In summary, I get your point, and I agree with you that according to classical theory there is no interaction between EM-fields in vacuum.

Unless I understood QED wrongly, you will only see appreciable effects for gamma photons.

Well, it helps to have high energy photons, but it's not necessary. It could be enough to have large fields. (E.g. see http://www.arxiv.org/abs/hep-ph/0510076 )

 

[pinestone]

And I can show you where using a different dielectric medium where this will NOT occur. Why? Because it depends ON THE MATERIAL! Try it! I'll suggest one: a photonic band gap material! Use light with energy LESS than the size of the photonic band gap. Apply as much magnetic field as you want. You'll NEVER get the light to be "deflected".
Learn condensed matter physics, especially optical transmission in solids, before you proclaim such a thing.
Zz.

That is exactly what I try and do. I'll refrain from generalizations after this post, and be much more specific with my comments. Thanks again for the information.