Help Solve a Question on Antisymmetrical Tensor Density

  • Context: Graduate 
  • Thread starter Thread starter diaoye
  • Start date Start date
  • Tags Tags
    Density Tensor
Click For Summary

Discussion Overview

The discussion revolves around a question related to antisymmetrical tensor density, specifically in the context of differential geometry and general relativity. Participants explore the difficulties faced by the original poster in understanding the concept and its application, referencing various sources and personal experiences with the topic.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Homework-related

Main Points Raised

  • The original poster expresses difficulty in understanding a question about antisymmetrical tensor density, despite having read Geroch's "Geometrical Quantum Mechanics."
  • Some participants inquire about the original poster's background and motivations, suggesting that the answer may depend on their level of understanding.
  • The original poster mentions self-study in general relativity and familiarity with tensors, but notes a lack of resources specifically addressing tensor density.
  • One participant asserts that understanding the properties of totally antisymmetric matrices is crucial, indicating that such matrices change sign when indices are swapped and suggesting that they are proportional to each other.
  • Another participant emphasizes the importance of familiarity with the Levi-Cevita symbol, metric transformations, and covariant derivatives in addressing the question.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best approach to the question, and multiple perspectives on the necessary background knowledge and resources remain evident.

Contextual Notes

Limitations include the original poster's unclear understanding of tensor density and the varying levels of background knowledge among participants, which may affect the clarity of the discussion.

diaoye
Messages
5
Reaction score
0
i have a question on antisymmetrical tensor density which i read on the internet
i read Geroch's "Geometrical Quantum Mechanics" but nothing changed.

here is the picture about this question http://p13.freep.cn/p.aspx?u=v20_p13_photo_1211140612144629_0.jpg

can anybody help me to solve it?
 
Last edited by a moderator:
Physics news on Phys.org
this is not a homework question, it's just a question i read on the internet and cannot find the solution
 
What is your background? Why are you interested? Which part gives you difficulty?

You can't just paste a high level differential geometry question and ask how it's answered. The answer will depend very much on what it is that you want to know. Solution, by itself, will look to you just as cryptic as the question unless you are very, very close to understanding it already.
 
K^2 said:
What is your background? Why are you interested? Which part gives you difficulty?

You can't just paste a high level differential geometry question and ask how it's answered. The answer will depend very much on what it is that you want to know. Solution, by itself, will look to you just as cryptic as the question unless you are very, very close to understanding it already.
i study general relativity by myself and did several exercises sucessifully, but only this i didn't understand. i can calculate tensors and the transformation of tensors, christoffel symbols, metrics etc. i read several books about general relativity, only Pauli's talked about tensor density, then i didnt pay much attention on it. Then i found this exercise which need the knowledge of tensor density that i could find few books talk about it, acctually only Pauli's and one on the internet.
 
You don't need to know anything special. It's all right there, really. You are given that [itex]g_{\mu \nu \alpha \beta}[/itex] is totally antisymmetric. That means that the matrix will change sign if you swap any two indices. For part one you just need to prove that any two matrices with such property are proportional to each other. That's just linear algebra.

The rest of it is pretty straight forward as well, so long as you know a bit about Levi-Cevita symbol, metric transformations, and covariant derivative. If you've worked with Christoffel symbol, you should have come across all that before.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 33 ·
2
Replies
33
Views
12K