EFE Metric: Find a Link to the Full Expansion

  • Context: Graduate 
  • Thread starter Thread starter HomogenousCow
  • Start date Start date
  • Tags Tags
    Terms
Click For Summary

Discussion Overview

The discussion revolves around the search for a fully expanded version of the Einstein Field Equations (EFE) in terms of the metric. Participants explore the implications of such an expansion, including its complexity and the challenges associated with it.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant requests a link to a fully expanded version of the EFE in terms of the metric.
  • Another participant mentions running out of Greek indices while attempting to write out the equations on paper.
  • Some participants note that the connection coefficients can be expanded in terms of the metric and its derivatives, questioning the necessity of a full expansion.
  • A later reply humorously suggests that the full expansion is desired for aesthetic appreciation of the equations.
  • One participant claims they can compute the components of the Einstein tensor for a general metric quickly using GrTensor, but acknowledges the impracticality of sharing such a lengthy result.
  • Another participant shares an experience of attempting to derive the EFE from a non-covariant differential equation, expressing frustration over the complexity and abundance of terms involved.

Areas of Agreement / Disagreement

Participants express varying levels of interest in the full expansion of the EFE, with some questioning its practicality and others appreciating the complexity. No consensus is reached regarding the necessity or utility of the full expansion.

Contextual Notes

Participants acknowledge the challenges of handling numerous terms and indices in the equations, indicating potential limitations in their approaches and the complexity of the topic.

Who May Find This Useful

This discussion may be of interest to those studying general relativity, mathematical physics, or anyone curious about the complexities of the Einstein Field Equations and their expansions.

HomogenousCow
Messages
736
Reaction score
213
Does anyone have a link to a version of the EFE fully expanded in terms of the metric?
 
Physics news on Phys.org
I'm trying to do this on a large piece of paper, finding myself running out of greek indices
 
It's not so bad in terms of the connection coefficients \Gamma^\mu_{\nu \lambda}, which can be expanded in terms of the metric and its derivatives. Why do you want it fully expanded? Just so you can bask in its fully glory?
 
stevendaryl said:
It's not so bad in terms of the connection coefficients \Gamma^\mu_{\nu \lambda}, which can be expanded in terms of the metric and its derivatives. Why do you want it fully expanded? Just so you can bask in its fully glory?

Pretty much, thought it would be interesting to see the EFE in it's "full glory".
 
HomogenousCow said:
Pretty much, thought it would be interesting to see the EFE in it's "full glory".

Raising the display limit to the 2.3 million words required to display it, I can compute the expression for the components of the Einstein tensor for a general metric in GrTensor in under a minute of CPU time.

It's a bit impractical to cut and paste the result here, though, due to its extreme length, and it wouln't really serve any purpose except to visually illustrate how messy it is.
 
Once, I tried to see if it was possible to get the Einstein Field Equations by starting with the non-covariant differential equation:

g^{\alpha \beta} \partial_\alpha \partial_\beta g_{\mu \nu} = K T_{\mu \nu}

and then adding correction terms in order to make it have the same form in any coordinate system. I quickly became lost in a sea of terms and indices. It's probably possible, but not a very efficient way to derive it.
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 31 ·
2
Replies
31
Views
1K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 37 ·
2
Replies
37
Views
2K
  • · Replies 186 ·
7
Replies
186
Views
13K
  • · Replies 22 ·
Replies
22
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K