Wave equation for Schwarzschild metric

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Homework Help Overview

The discussion revolves around the wave equation in the context of the Schwarzschild metric, specifically focusing on the calculation of the d'Alembertian operator $$\nabla_{\mu}\nabla^{\mu} \Phi$$ for a given metric. The original poster presents their calculations and seeks validation or simplification of their results.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • The original poster attempts to compute the d'Alembertian operator using the provided metric and expresses uncertainty about the correctness and potential simplification of their result. Some participants suggest resources for further study, while others discuss the appropriateness of sharing book recommendations in the forum.

Discussion Status

The discussion is ongoing, with participants exploring different aspects of the problem. Some guidance has been offered in the form of book recommendations, and there is a general acknowledgment of the importance of providing hints rather than direct answers.

Contextual Notes

Participants express concern about adhering to forum rules regarding the sharing of resources and the nature of responses in homework contexts.

Arman777
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Homework Statement
Wave equation for Schwarzschild metric
Relevant Equations
GR equations
I am trying to find the $$\nabla_{\mu}\nabla^{\mu} \Phi$$ for $$ds^2 = (1 - \frac{2M}{r})dt^2 + (1 - \frac{2M}{r})^{-1}dr^2 + r^2d\Omega^2$$

I have did some calculations by using

$$\nabla_{\mu}\nabla^{\mu}\Phi = \frac{1}{\sqrt{-g}}\partial_{\mu}(\sqrt{-g}g^{\mu \nu}\partial_{\nu}\Phi)$$

and I have found

$$\nabla_{\mu}\nabla^{\mu} \Phi = [g^{tt}\partial^2_t + 2(\frac{1}{r} - \frac{M}{r^2})\partial_r + g^{rr}\partial^2_r + \frac{cot(\theta)}{r^2}\partial_{\theta} + g^{\theta \theta}\partial^2_{\theta} + g^{\phi \phi}\partial^2_{\phi}]\Phi$$

but I am not sure that is this true or it can be further simplified ? Any ideas
 
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Hello, @Arman777 . I am recently studying this problem. I would suggest Spacetime and geometry by Sean M. Carroll, especialy in pages 395 to 400.

Will I violate any rules in this forum if I just suggest a book?
 
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Of course not. Of course you violate rules, if you link to some illegal download-link to a copyrighted book.
 
vanhees71 said:
Of course not. Of course you violate rules, if you link to some illegal download-link to a copyrighted book.
Thanks! Sometimes I hesitate to answer in homework forum, because not only there are too many professors, but I am afraid I would give the answer directly which would violate the rules.
 
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Don't worry about the "professors". They are also just human beings. Not giving directly the answer is also my problem with the homework forums, but it's of course much better to give only hints first and let the student find the solution him or herself.
 
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