Chern-Simons and massive A^{\mu}

In summary, the conversation discusses the use of a Chern-Simons Lagrangian and its corresponding field equations to show that the field satisfies the Klein-Gordon equation. The concept of introducing the dual of the field strength is also mentioned.
  • #1
IRobot
87
0
Hi, I am struggling with a problem in field theory:
We are looking at a Chern-Simons Lagrangian describing a massive A field:
[itex]L = -\frac{1}{4} F^{\mu\nu}F_{\mu\nu}+\frac{m}{4}\epsilon^{\mu\nu \rho}F_{\mu\nu}A_{\rho}[/itex]
I find those field equations:
[itex]\partial_{\mu}F^{\mu\lambda}=-\frac{m}{2} \epsilon^{\lambda\mu\nu}F_{\mu\nu}[/itex] and now I need to show that F satisfies the Klein-Gordon equation: [itex](\Box+m^2)F_{\mu\nu}=0[/itex] using the EL equations, but after a time playing with both equations, I still can't prove that.
 
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  • #2
It's normal here to introduce the dual of the field strength

[tex]\tilde{F}^\lambda = \frac{1}{2} \epsilon^{\lambda\mu\nu}F_{\mu\nu}.[/tex]

Then taking the divergence of your equation of motion above yields [itex] \partial_\lambda \tilde{F}^\lambda = 0,[/itex] while multiplying by an appropriate epsilon yields the KG equation for [itex]\tilde{F}^\lambda[/itex].
 
  • #3
fzero said:
It's normal here to introduce the dual of the field strength

[tex]\tilde{F}^\lambda = \frac{1}{2} \epsilon^{\lambda\mu\nu}F_{\mu\nu}.[/tex]

Then taking the divergence of your equation of motion above yields [itex] \partial_\lambda \tilde{F}^\lambda = 0,[/itex] while multiplying by an appropriate epsilon yields the KG equation for [itex]\tilde{F}^\lambda[/itex].
Thanks a lot. I did manage to find the Klein Gordon equation for the dual, then it's just a matter of applying another LeviCivita to find it for the "regular" form. ;)
 

1. What is the Chern-Simons term in the context of quantum field theory?

The Chern-Simons term is a gauge invariant term that is added to the usual action in quantum field theory. It is used to describe topological properties of gauge fields and is particularly important in theories with massless gauge fields.

2. What is the significance of the Chern-Simons term in particle physics?

The Chern-Simons term is significant in particle physics because it can give rise to mass terms for gauge fields, which are essential for describing the weak interactions of particles. It also plays a crucial role in understanding the behavior of quantum Hall systems.

3. How does the Chern-Simons term contribute to the mass of A^{\mu} in a gauge theory?

The Chern-Simons term contributes to the mass of A^{\mu} in a gauge theory by introducing a mass term for the gauge field. This is achieved by coupling the gauge field to a scalar field, which acquires a vacuum expectation value, breaking the gauge symmetry and giving mass to the gauge field.

4. Can the Chern-Simons term be used to generate massive gauge bosons in the Standard Model?

Yes, the Chern-Simons term can be used to generate massive gauge bosons in the Standard Model. In fact, the Higgs mechanism, which gives mass to the W and Z bosons, can be seen as a special case of the Chern-Simons term in the electroweak theory.

5. Are there any experimental implications of the Chern-Simons term in particle physics?

Yes, there are experimental implications of the Chern-Simons term in particle physics. For example, it can lead to anomalous processes, such as the decay of a neutral pion into two photons, which violates the conservation of parity and charge conjugation. These processes have been observed in experiments, providing evidence for the presence of the Chern-Simons term in the Standard Model.

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