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

Field equations Einstein-Gauss-Bonnet action

  1. Dec 8, 2014 #1
    Hello everyone!
    I have a "great" problem with EGB action. First of all, I'm used to work with potential and scalar field, but now I have the following action
    ##S=\int\sqrt{-g}\left(2\beta +R+\alpha GB\right)d^6 x##

    where GB is the six-dimensional Gauss-Bonnet term, R is the scalar curvature and ##2\beta## is a cosmological constant. ##\alpha## is a coupling parameter. Well, I want to write Einstein equations, but I don't know how to calculate stress-energy tensor ##T##... Thanks in advance
     
  2. jcsd
  3. Dec 8, 2014 #2

    Chalnoth

    User Avatar
    Science Advisor

    See the derivation of the four-dimensional einstein field equations:
    http://www.science20.com/standup_ph...d_equation_derivation_about_dozen_steps-90263

    Basically, you add the matter action to the gravitational action above.
     
  4. Dec 8, 2014 #3
    Thanks :) but in my case we are in six dim not four... Then, there is no matter terms... My professor says this...
     
  5. Dec 8, 2014 #4

    Chalnoth

    User Avatar
    Science Advisor

    If you're not going to have any matter terms, then you're not going to have a stress-energy tensor. The analog to the Einstein field equations without any matter action would have some terms related to spatial curvature set equal to zero.
     
  6. Dec 8, 2014 #5
    very thanks :)
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Field equations Einstein-Gauss-Bonnet action
  1. Beyond Einstein (Replies: 3)

  2. Gauss-Bonnet term (Replies: 2)

Loading...