Question from Weinberg's cosmology text

In summary: That is absolutely correct. And the key to deriving it is to use the two unnumbered equations below 10.9.6 in Weinberg's "Gravitation and Cosmology" book.I think I've figured out the answer to my question, but if you have any insights on that you're very welcome to let me know.
  • #1
blueeyedblond
3
0
I am trying to learn gauge issues in cosmology from Weinberg's "Cosmology". However, I am completely stumped at how he gets 5.3.4 from 5.3.3. I was doing great until that point and now I'm going crazy. Any help would be highly appreciated!
 
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  • #2
He doesn't.

He wants to show that 5.3.5 (i) reduces to 5.3.4 in the absence of gravitation (ii) further that 5.3.5 is a scalar. (i) is obvious, (ii) he follows the reasoning 5.2.12 and 5.2.13.
 
  • #3
atyy said:
He doesn't.

He wants to show that 5.3.5 (i) reduces to 5.3.4 in the absence of gravitation (ii) further that 5.3.5 is a scalar. (i) is obvious, (ii) he follows the reasoning 5.2.12 and 5.2.13.


atyy,

Thanks so much for taking the time to reply!

However, I was referring to the recent book "Cosmology" by Weinberg and not the older "Gravitation and Cosmology" which is what you seem to be referring to to. (For a moment I thought you're a crazy person!)

I think I've figured out the answer to my question, but if you have any insights on that you're very welcome to let me know.

Sorry for the confusion!
 
  • #4
Ah ha ha ha! Sorry about that! (But I am a crazy person :smile:)
 
  • #5
I don't know if this will help you or not, but (5.3.4) is nothing but the minus Lie derivative of the unperturbed metric with respect to the vector field [tex]\epsilon^\lambda(x)[/tex]. So it describes the rate of change of the metric dragged along the trajectories of [tex]\epsilon[/tex] with respect to the original metric.
 
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  • #6
arkajad said:
I don't know if this will help you or not, but (5.3.4) is nothing but the minus Lie derivative of the unperturbed metric with respect to the vector field [tex]\epsilon^\lambda(x)[/tex]. So it describes the rate of change of the metric dragged along the trajectories of [tex]\epsilon[/tex] with respect to the original metric.

That is absolutely correct. And the key to deriving it is to use the two unnumbered equations below 10.9.6 in Weinberg's "Gravitation and Cosmology" book.
 

1. What is Weinberg's cosmology text about?

Weinberg's cosmology text is a book that discusses the theories and concepts related to the origin, structure, and evolution of the universe.

2. Who is the author of Weinberg's cosmology text?

The author of Weinberg's cosmology text is Steven Weinberg, a Nobel Prize-winning physicist.

3. What are some key topics covered in Weinberg's cosmology text?

Some key topics covered in Weinberg's cosmology text include the Big Bang theory, the expanding universe, dark matter and dark energy, and the cosmic microwave background radiation.

4. Is Weinberg's cosmology text suitable for non-scientists?

Weinberg's cosmology text is written for a general audience and does not require a deep understanding of physics or mathematics. However, some background knowledge in these subjects may be helpful in fully understanding the concepts presented.

5. Does Weinberg's cosmology text offer any new insights or theories?

Weinberg's cosmology text presents a comprehensive overview of current theories and research in cosmology. While it may not offer any groundbreaking new theories, it provides a thorough understanding of the current state of the field.

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