I just read in Griffiths 'Electrodynamics' (chapter 12.3) how

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Discussion Overview

The discussion revolves around the nature of forces in physics, particularly focusing on the weak and strong forces in relation to magnetism and the electromagnetic force. Participants explore whether magnetism exists in these forces and how it might be observable, drawing comparisons with the electromagnetic force as described in Griffiths' 'Electrodynamics'.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants question whether the weak and strong forces have an associated magnetism similar to that of the electromagnetic force.
  • One participant asserts that magnetism is an aspect of the electromagnetic force, suggesting that electric and magnetic forces are intertwined due to relativity.
  • Another participant raises the idea that different observers experience electric and magnetic forces differently, prompting questions about the nature of strong and weak charges.
  • Concerns are expressed about the lack of responses to the initial questions regarding the existence of strong-magnetic and weak-magnetic forces.
  • Some participants clarify that while there are "electric" and "magnetic" forces in quantum chromodynamics (QCD) and electroweak theory, they do not manifest in the same way as in quantum electrodynamics (QED).
  • One participant mentions the concept of "chromomagnetic" forces in QCD, noting that these forces are less useful than in QED due to gauge invariance issues.
  • A later reply introduces the idea of chromomagnetic monopoles in the context of quark confinement, suggesting an area where this aspect may be physically relevant.

Areas of Agreement / Disagreement

Participants express a range of views on the existence and nature of magnetism in the weak and strong forces, with no consensus reached on whether these forces have analogous magnetic aspects to the electromagnetic force.

Contextual Notes

Discussions include references to gauge invariance and the mathematical nature of forces in QCD and electroweak theory, highlighting limitations in how these forces are understood compared to electromagnetism.

Who May Find This Useful

This discussion may be of interest to those studying theoretical physics, particularly in the fields of quantum field theory and particle physics, as well as students exploring the relationships between different fundamental forces.

Lapidus
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I just read in Griffiths 'Electrodynamics' (chapter 12.3) how magnetism is a relativistic phenomenom, why there had to be a thing like magnetism just given electrostatics and relativity.

Is the same true for the weak force and the strong force? Is there also magnetism? If so, how is it observable?

thanks
 
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Lapidus said:
Is the same true for the weak force and the strong force? Is there also magnetism? If so, how is it observable?

What do you mean by "is there also magnetism?". Of course there is, take two magnetic dipoles and play with them. And Magnetism is an "aspect" of the electromagnetic force, if that is answering your question.
 


We have electric charges, whith them there are associated an electric force and a magnetic force.

Due to relativity, magnetic and electric force rotate into each other. Different observers feel/ observe the electromagnetic field, described by an antisymmetric 2-rank tensor, differently.

What about the strong and weak charges, have they also a kind of magnetic force? Do different observeres feel different forces, like in EM observer do with the magnetic and the electric force?
 


So what's up here? Is my question complete bogus or why is no one replying?

We got
- gluons and the strong force
- W, Z bosons and the weak force
- photons and the electro-magnetic force

Why don't we have a strong-magnetic and a weak-magnetic force, too?
 


Yet another rephrasing of my question.

Why are photons associated with two forces, the magnetic and electric force, but the gluons and W,Z bosons only with one (the strong and the weak)?
 


There is not an electric force and a magnetic force. There is only the electromagnetic force. This is clear when using the relativistic notation. Electricity and magnetism go hand in hand.

I don't know enough QFT to answer your other questions.
 


eXorikos said:
There is not an electric force and a magnetic force. There is only the electromagnetic force. This is clear when using the relativistic notation. Electricity and magnetism go hand in hand.

I don't know enough QFT to answer your other questions.

Right. And as stated in an earlier post, due to relativity, magnetic and electric force rotate into each other. Different observers feel/ observe the electromagnetic field, described by an antisymmetric 2-rank tensor, differently.

But why are there two aspects, two observer dependent forces, i.e. electricity and magnetism, when it comes the photon/ the electromagneti force?

Why is that not for the gluon/strong force and W,Z bosons/weak force?
 


There are "electric" and "magnetic" forces for all of the forces, including QCD and electroweak. Indeed, you often hear people in nuclear physics talking about the "Chromomagnetic operator", which is the generalization of the magnetic force in QED.

However, it's not quite as useful as it is in QED, since these "forces" don't manifest themselves in the same way. Since the gluons have color charge, that means that the chromoelectric and chromomagnetic force fields are not "gauge invariant". This is very different than QED, where the photon is neutral and the E and B fields are "physical".

So the short answer is that there ARE such things as "electric" and "magnetic" fields in these other forces, but they are very different than the QED version, and are more "mathematical analogies" rather than actual physical objects.

BTW: there are also "gravitoelectric" and "gravitomagnetic" fields in General Relativity. Same kind of thing.

Hope that helps.
 


In fact, there is at least one area where the "chromomagnetic" aspect of the strong force is kind of physical. There is the so-called dual superconductor picture of confinement which asserts that quark confinement is due to a condensation of chromomagnetic monopoles. This is of course not a gauge invariant statement but still a mechanism that has its merits and is actively investigated today.
 
  • #10


Thank you, Blechman and hch71!

Great answers!
 

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