Please give me some clues about the calculations for a non-rotating black hole

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SUMMARY

The discussion focuses on the dimensional consistency of equations related to non-rotating black holes, specifically questioning the argument of the natural logarithm function in the context of the equation (8.13). Participants agree that the form should be adjusted to ##|r/r^* - 1|## for consistency. Additionally, Sean Carroll's notes on General Relativity, particularly regarding Kruskal coordinates, are recommended as a valuable resource for understanding these concepts. Key equations from Carroll's notes, especially (7.74) and (7.75), are highlighted for their relevance to the discussion.

PREREQUISITES
  • Understanding of General Relativity concepts
  • Familiarity with Kruskal coordinates
  • Knowledge of logarithmic functions in mathematical physics
  • Ability to interpret equations in the context of black hole physics
NEXT STEPS
  • Study Sean Carroll's General Relativity notes, focusing on Kruskal coordinates
  • Review the implications of dimensional consistency in physical equations
  • Analyze the significance of equations (7.74), (7.75), and (7.76) in Carroll's work
  • Explore the mathematical properties of logarithmic functions in physics
USEFUL FOR

Students and researchers in theoretical physics, particularly those focusing on black hole mechanics and General Relativity, will benefit from this discussion.

park
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Homework Statement
non-rotating black holes
Relevant Equations
Kruskal coordinates
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The right-hand side doesn't look dimensionally consistent to me. Could it be that the argument of the ##ln## function should be something like ##|r/r^* - 1|## instead of ##|r - r^*|##?

It's a bit hard to check your work since you haven't indicated how ##p## and ##q## are defined.
 
oops! my mistake! p and q is defined ...
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i finally got a clue with your comment about dimensions!
For consistency of dimension, i think r-r* of (8.13) should be r/r*-1
 
park said:
i finally got a clue with your comment about dimensions!
For consistency of dimension, i think r-r* of (8.13) should be r/r*-1
Yes, things seem to work out better with the r/r*-1 form.

I'm not very familiar with Kruskal coordinates. Sean Carroll's notes on GR are freely available on the internet.
https://www.preposterousuniverse.com/grnotes/

He discusses Kruskal coordinates in this chapter:
https://preposterousuniverse.com/wp-content/uploads/grnotes-seven.pdf
The relevant material starts around page 182. Note equation (7.74) on page 186. I think his ##\tilde u## and ##\tilde v## are similar to your ##p## and ##q##, and his ##u'## and ##v'## are essentially your ##p'## and ##q'##. (But I believe Carroll is missing an overall negative sign in his expressions for ##v'## in (7.75) and (7.76). He corrects this in his published textbook.).
 

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