Self-dual and Anti Self-dual antisymmetric tensor

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In summary, according to Weinberg, the (1,0) and (0,1) fields correspond to an antisymmetric tensor that satisfies the further irreducibility conditions. The self-dual and anti-selfdual tensors are complex combinations of the original three tensors, and the Lorentz group is a direct product of the two groups generated by the two rotations.
  • #1
wphysics
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I am working on Chapter 5.6 of Weinberg QFT book vol1.

In page 231 and 232, he said (1,0) or (0,1) field corresponds to an antisymmetric tensor
[itex]
F^{\mu\nu}
[/itex]
that satisfies the further irreducibilitry 'duality' conditions
[itex]
F^{\mu\nu}= \pm {{i}\over{2}} \epsilon ^{\mu\nu\lambda\rho}F_{\lambda \rho}
[/itex]
for (1,0) and (0,1) fields, respectively.

I check that Self-dual antisymmetrc tensor has three independent components and so does Anti Self-dual antisymmetric tensor. So, I can guess that there might be correspondence between Self-dual(or Anti Self-dual) antisymmetric tensor and (1,0) field (or (0,1)field ).

But, I could not show how they are related to each other mathematically.

I would like you guys to show me that how we correspond Self-dual antisymmetric tensor with (1,0) field and
Anti Self-dual antisymmetric tensor with (0,1) field.

Thank you so much.
 
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  • #2
Given Fμν, we define its dual as Fμν* = ½εμνστFστ. The self-dual and anti-selfdual tensors are complex combinations,
SFμν = Fμν + iFμν* and AFμν = Fμν - iFμν*.

It's easier to represent the F's as a pair of 3-vectors, Fμν = (E, B). Then Fμν* = (B, -E), SFμν = (E + iB, B - iE), and AFμν = (E - iB, B + iE).

This shows that SFμν and AFμν each have only three complex components.

Under a space rotation, all of these 3-vectors behave the same way. Under an infinitesimal rotation about an axis with unit vector ω, a 3-vector V transforms as dV = ω x V, and this applies equally well to E, B and E ± iB. The generators for spatial rotations are denoted J.

Under a finite boost, E' = γ(E + β x B), B' = γ(B - β x E), and the infinitesimal form of this is dE = β x B, dB = - β x E. Then d(E + iB) = β x (B - iE) = -i β x (E + iB) and d(E - iB) = i β x (E - iB). The generators for boosts are denoted K.

The Lorentz group is a direct product of two groups generated by J + iK and J - iK. I'm getting tired of writing down all the details, but if you combine the above results and calculate how (E ± iB) transform under (J ± iK), you'll find the changes add in one case and cancel in the other, indicating that these quantities transform exactly as the (1,0) and (0,1) representations must.
 
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  • #3
Sir(Bill_K),
can you give me some reference on this topic.
 

What are self-dual and anti self-dual antisymmetric tensors?

Self-dual and anti self-dual antisymmetric tensors are mathematical objects that describe the symmetries of physical systems. They are represented by matrices or arrays of numbers, and are used in various fields of physics, particularly in electromagnetism and quantum field theory.

What is the difference between self-dual and anti self-dual antisymmetric tensors?

The main difference between self-dual and anti self-dual antisymmetric tensors lies in their transformation properties under certain operations. Self-dual tensors do not change when subjected to a particular transformation, while anti self-dual tensors do change under the same transformation.

How are self-dual and anti self-dual antisymmetric tensors used in physics?

Self-dual and anti self-dual tensors are used to describe the symmetries of physical systems, particularly those involving electromagnetic fields and quantum particles. They also play a crucial role in the formulation of gauge theories, which are used to describe fundamental interactions in physics.

What are some examples of self-dual and anti self-dual antisymmetric tensors?

Some examples of self-dual tensors include the electromagnetic field tensor and the Yang-Mills field strength tensor. Examples of anti self-dual tensors include the dual of the electromagnetic field tensor and the dual of the Yang-Mills field strength tensor.

What are the applications of self-dual and anti self-dual antisymmetric tensors?

Self-dual and anti self-dual tensors have many applications in physics, including in the study of electromagnetism, quantum field theory, and string theory. They are also used in engineering and image processing, particularly in the analysis of magnetic and optical fields.

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