Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Curvature of a group manifold

  1. Feb 11, 2016 #1
    So I'm working with some group manifolds.
    The part that's getting to me is the Ricci scalar I'm using to describe the curvature.

    I have identified the groups that I'm using but that's not really relevant at the moment.
    We're using a left-invariant metric ##\mathcal{M}_{ab}##.

    Now I've got the expression
    $$R = -\frac{1}{4}f_{abc}f^{abc} -\frac{1}{2}f_{cab}f^{abc} = -\frac{1}{4}\mathcal{M}_{ad}\mathcal{M}^{be}\mathcal{M}^{cf} f^a_{\,\,\,\, bc}f^d_{\,\,\,\, ef} - \frac{1}{2}\mathcal{M}^{cd}f^a_{\,\,\,\, bc} f^b_{\,\,\,\, ad}$$

    The second expression (with explicit metrics) is the one I'll be using later on because I can normalise structure constants of that kind. That is however not important, going from the first part to the second is comparatively easy.

    I'm wondering if there's an easy way to find the Ricci scalar (or tensor for that matter) that doesn't require looking at the sectional curvature. This last part is important because it would take me too far from the topic.
    Meanwhile all examples I found do use this notion.

    I want to know this because I like to be as complete as possible in my notes.

    Thanks,

    Joris
     
  2. jcsd
  3. Feb 16, 2016 #2
    Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook