Rank 3 tensor created by taking the derivative of electromagnetic field tensor

AI Thread Summary
The discussion centers on demonstrating that the rank 3 tensor S_{\alpha \beta \gamma} is completely antisymmetric, defined as S_{\alpha \beta \gamma} = F_{\alpha \beta , \gamma} + F_{\beta \gamma , \alpha} + F_{\gamma \alpha , \beta}. Participants express discomfort with the concept, questioning the similarity of the three terms involved. To prove antisymmetry, one must show that swapping any two indices results in a sign change, specifically S_{\alpha \beta \gamma} = -S_{\alpha \gamma \beta} and similar for other index pairs. Additionally, the implications of S_{\alpha \beta \gamma} equating to zero are raised, suggesting a deeper significance in the context of electromagnetic fields. Understanding these properties is essential for grasping the behavior of rank 3 tensors in physics.
mjordan2nd
Messages
173
Reaction score
1

Homework Statement



Show that the rank 3 tensor S_{\alpha \beta \gamma}=F_{\alpha \beta , \gamma} + F_{\beta \gamma , \alpha} + F_{\gamma \alpha , \beta} is completely antisymmetric.

I just don't feel comfortable doing this stuff at all. Each of the three terms seems like they should be exactly the same to me. Could someone show me how I would start doing something like this please? Furthermore, if this is a rank 3 tensor, what would it mean if this tensor equals 0?

Thanks. :-\
 
Physics news on Phys.org
If S_{\alpha\beta\gamma} is completely antisymmetric, then

S_{\alpha\beta\gamma}=-S_{\alpha\gamma\beta}
S_{\alpha\beta\gamma}=-S_{\beta\alpha\gamma}

and

S_{\alpha\beta\gamma}=-S_{\gamma\beta\alpha}

That is, S_{\alpha\beta\gamma} is antisymmetric on all pairs of indices...

So, start by comparing S_{\alpha\beta\gamma} to S_{\alpha\gamma\beta} using the definition you posted...
 
Thread 'Help with Time-Independent Perturbation Theory "Good" States Proof'
(Disclaimer: this is not a HW question. I am self-studying, and this felt like the type of question I've seen in this forum. If there is somewhere better for me to share this doubt, please let me know and I'll transfer it right away.) I am currently reviewing Chapter 7 of Introduction to QM by Griffiths. I have been stuck for an hour or so trying to understand the last paragraph of this proof (pls check the attached file). It claims that we can express Ψ_{γ}(0) as a linear combination of...
Back
Top