Does a photon carry a magnetic field?

Click For Summary
SUMMARY

Photons do not carry a magnetic field; rather, they are quantized excitations of the electromagnetic field. The magnetic field is generated by accelerating electric charges, not by photons themselves. While photons can be associated with electromagnetic waves, they do not serve as sources of magnetic fields. The classical description of light is governed by Maxwell's equations, which depict light as waves rather than particles.

PREREQUISITES
  • Understanding of Maxwell's equations
  • Familiarity with electromagnetic fields
  • Basic knowledge of quantum mechanics
  • Concept of quantization in physics
NEXT STEPS
  • Study the implications of Maxwell's equations on electromagnetic wave propagation
  • Explore the concept of quantization in quantum electrodynamics
  • Investigate the role of accelerating charges in generating electromagnetic fields
  • Learn about the differences between classical and quantum descriptions of light
USEFUL FOR

Students of physics, educators, and anyone interested in the fundamental principles of electromagnetism and quantum mechanics.

  • #31
Polyrhythmic said:
The magnetic monopole would play the same role as the electric charge, it would be a source for the magnetic field, not a quantization.

Why would it not be a quantization of the magnetic field, if it is itself, a particle?
 
Physics news on Phys.org
  • #32
Goldstone1 said:
Why would it not be a quantization of the magnetic field, if it is itself, a particle?

For the same reason the electron is no quantization of the electric field. I think you're mistaken on what we mean by "quantization of the field". If we look at a traveling electromagnetic wave, quantum mechanically, energy is transferred in discrete packages. Those packages are what we call photons, quanta of the field. The charge would be merely the source.
 
  • #33
Goldstone1 said:
Why would it not be a quantization of the magnetic field, if it is itself, a particle?

But that is not quantization. If you allow for magnetic monopoles, just as we already allow for electric monopoles, then the magnetic field will still be continuous. The quantization of the field means that the energy is quantized. Since a monopole will produce a field of continuous magnitude, there is no quantization of the field.

EDIT: It appears I lost this one by a nose.
 
  • #34
Born2bwire said:
But that is not quantization. If you allow for magnetic monopoles, just as we already allow for electric monopoles, then the magnetic field will still be continuous. The quantization of the field means that the energy is quantized. Since a monopole will produce a field of continuous magnitude, there is no quantization of the field.

EDIT: It appears I lost this one by a nose.

Hah, gotcha! But I still think that a variety of explanations is beneficial, as long as they are not contradictory!
 
  • #35
Born2bwire said:
But that is not quantization. If you allow for magnetic monopoles, just as we already allow for electric monopoles, then the magnetic field will still be continuous. The quantization of the field means that the energy is quantized. Since a monopole will produce a field of continuous magnitude, there is no quantization of the field.

EDIT: It appears I lost this one by a nose.

It's ok, we all make mistakes. :P
 
  • #36
sophiecentaur said:
Before you bring Feynman into a discussion I think you should make sure that you understand just what he did say and didn't say. The 'squiggle' on a Feynman diagram in no way tells us that a particle goes from place to place, for example - can you find any evidence of his actually saying that it does?

There are a million miles between the separate ideas of quanta and particles.

you go me watching his lecture again, I think the 3rd time now :)

He catagorically states "light is particles NOT waves". and shows how experiment demonstrated that using a PM tube. "waves can explain many things, but not light, light is particles"

http://vega.org.uk/video/programme/45"

specifically, if you don't want to sit through the whole lecture... 36mins in and 48mins in


just stirring you up with the... heresy heresy I cry comment ;) but since you asked for a reference from him, I gave it :)

I am NO physicist, just a basic understanding of some things. you could baffle me with maths in an instant. But I will put my trust, on this subject, in some one with a Nobel Prize ;)

cheers
Dave
 
Last edited by a moderator:
  • #37
davenn said:
you go me watching his lecture again, I think the 3rd time now :)

He catagorically states "light is particles NOT waves". and shows how experiment demonstrated that using a PM tube. "waves can explain many things, but not light, light is particles"

http://vega.org.uk/video/programme/45"

specifically, if you don't want to sit through the whole lecture... 36mins in and 48mins in


just stirring you up with the... heresy heresy I cry comment ;) but since you asked for a reference from him, I gave it :)

I am NO physicist, just a basic understanding of some things. you could baffle me with maths in an instant. But I will put my trust, on this subject, in some one with a Nobel Prize ;)

cheers
Dave

But again, the qualifier in the quote that you contested was that classically, light is waves and this is unequivocal in my opinion. The particle behavior of light does not arise unless you go to quantum electrodynamics (although we can certainly see particle behavior using classical experiments but classical theory fails to account for it). But I would even caution against labelling it as a corpuscle as that carries a very classical definition. The quantum field theory particle is not truly corpuscular, it is an amalgamation of what we classically think of as a wave and a particle.
 
Last edited by a moderator:
  • #38
Born2bwire said:
. . . . But I would even caution against labelling it as a corpuscle as that carries a very classical definition. The quantum field theory particle is not truly corpuscular, it is an amalgamation of what we classically think of as a wave and a particle.

Yes. The problem with trying to think in terms of particles in the conventional sense is that they have to have zero extent, for a start. I say that because, would not their 'size' relate, in some way to their wavelength? This would lead to the lowest energy photons (the 'biggest' ) being the size of a mountain or a house, if you extend the implied size of light photons so that seems a non-starter for a good model. So how would these infinitely small particles be expected to interact with the structures they encounter as they would mostly be encountering empty space (analogous to the results of Rutherford scattering)?
To explain how they actually could interact, you'd have to give them some field around them so why not stick with the EM wave to explain it all. The Quantisation aspect need only refer to the energy needed for an interaction to occur and needn't involve these little bullets - except as a useful shorthand, which I agree is useful.
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 22 ·
Replies
22
Views
2K
  • · Replies 7 ·
Replies
7
Views
13K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 28 ·
Replies
28
Views
3K
  • · Replies 42 ·
2
Replies
42
Views
3K