Hi all,(adsbygoogle = window.adsbygoogle || []).push({});

I'm hoping someone can help me out as I'm really stuck.

With reference to the top of page 7 at http://faculty.washington.edu/mrdepies/Survey_of_Dark_Energy2.pdf

I'd like to know how to get the quoted energy density and pressure of phi from the stress-energy tensor. Im very new to tensors and the notation involved. There are times I think I understand what is going on, but then I find I can't do simple problems, like get the pressure from the stress energy tensor.

The way I'd get the energy density is by setting all indices in the stress-energy tensor to 0, but I'm not sure if that's correct?

What would help me out massivly is a step by step way to get these answers (or point me to a site that explains how to get them, I've yet to find one). Once I understand this, I suspect a lot of other stuff I've been reading about will fall into place.

Thanks in advance to anyone who can help

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Scalar field pressure and energy density

**Physics Forums | Science Articles, Homework Help, Discussion**