Gravitational Wave Energy Transported by Unit Area

quasar987
Science Advisor
Homework Helper
Gold Member
Messages
4,796
Reaction score
32

Homework Statement


I am given the form of the perturbation in the metric:

h_{\mu\nu}=\left(\begin{array} {cccc} 0&0&0&0 \\ 0&1&0&0\\ 0&0&-1&0 \\ 0&0&0&0\end{array}\right) \gamma e^{-(z-t)^2}

Where gamma<<1. That is to say, g_{\mu\nu}(\mathbf{r},t)=\eta_{\mu\nu}+h_{\mu\nu}(\mathbf{r},t) (we use (+---) for eta (Minkowski))

h (or rather, all 16 of its terms) has the form of a plane wave sailing in the z direction at the speed of light c=1.

I am simply asked to find the gravitational energy transported by (transerse) unit area by the wave from t=-infty to t=+infty.

The Attempt at a Solution


I was about to write h as a Fourier integral but I don't know what I'm going to do after that, so is this even a good start?
 
Last edited:
Thread 'Need help understanding this figure on energy levels'
This figure is from "Introduction to Quantum Mechanics" by Griffiths (3rd edition). It is available to download. It is from page 142. I am hoping the usual people on this site will give me a hand understanding what is going on in the figure. After the equation (4.50) it says "It is customary to introduce the principal quantum number, ##n##, which simply orders the allowed energies, starting with 1 for the ground state. (see the figure)" I still don't understand the figure :( Here is...
Thread 'Understanding how to "tack on" the time wiggle factor'
The last problem I posted on QM made it into advanced homework help, that is why I am putting it here. I am sorry for any hassle imposed on the moderators by myself. Part (a) is quite easy. We get $$\sigma_1 = 2\lambda, \mathbf{v}_1 = \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} \sigma_2 = \lambda, \mathbf{v}_2 = \begin{pmatrix} 1/\sqrt{2} \\ 1/\sqrt{2} \\ 0 \end{pmatrix} \sigma_3 = -\lambda, \mathbf{v}_3 = \begin{pmatrix} 1/\sqrt{2} \\ -1/\sqrt{2} \\ 0 \end{pmatrix} $$ There are two ways...
Back
Top