Dual Faraday Tensor - Levi Civita Problem

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Homework Help Overview

The discussion revolves around the calculation of the Dual Faraday Tensor using the Levi-Civita symbol in the context of tensor notation and properties. Participants are exploring the relationships and signs associated with permutations of indices in a 4x4 matrix representation.

Discussion Character

  • Conceptual clarification, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants are attempting to clarify the correct application of the Levi-Civita symbol in relation to the Dual Faraday Tensor. Questions arise regarding the number of terms generated and the correctness of signs associated with specific permutations.

Discussion Status

Some participants have acknowledged corrections regarding the parity of permutations and the implications for the tensor calculations. There is an ongoing exploration of the correct signs and terms, with no explicit consensus reached yet.

Contextual Notes

Participants are grappling with the notation and properties of the Levi-Civita symbol, particularly in the context of tensor calculations, which may involve assumptions about index permutations and their associated signs.

MidnightR
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Ok I'm trying to calculate the Dual Faraday Tensor, but I'm having trouble with the notation I think...

[itex]*F^{ab} = \frac{1}{2}E^{abcd}F_{cd}[/itex] where E is the levi-civita symbol.

I'm correct in that

E^(1234) =

1 for (1234,3412,2341,4123)
-1 for (4321,3214,2143,1432)
0 otherwise

But this only gives me 8 terms in my 4x4 matrix? Which is incorrect?

F_cd is the Faraday tensor, which is also a 4x4 matrix.
 
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MidnightR said:
I'm correct in that

E^(1234) =

1 for (1234,3412,2341,4123)
-1 for (4321,3214,2143,1432)
0 otherwise

But this only gives me 8 terms in my 4x4 matrix? Which is incorrect?

You are both missing permutations like 1324 and you have the wrong sign on others. For example, 2341 and 4123 are both odd, while 2143 and 4321 are even.
 
You're right, thanks. It works now.
 
So 1324 is odd and 3214 is even. Correct?
 
No, because [itex]\epsilon^{1324} = - \epsilon^{3124} = - \left( - \epsilon^{3214}\right)[/itex], so that when the first is odd (and it is), the last is odd as well.
 
Thank's.
 

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