Cosmological constant as a perfect fluid

1. Feb 2, 2008

EDerkatch

Hi everyone,

If anyone could point me in the right direction with this problem I'd really appreciate it.

"Show that the cosmological constant can be interpreted as a perfect fluid having an equation of state w=-1."

I have a rough idea of how to do the second part of the proof: if the cosmological constant can be interpreted as a perfect fluid then

ρ(dot)+3(a(dot)/a)(ρ+P)=0 (conservation equation)=>ρ+P=0 due to the continuity of a perfect fluid.

But how do I show that it can be interpreted as a perfect fluid?

2. Feb 2, 2008

Dick

"If w=(-1) for a perfect fluid then rho+p=0. So by the conservation equation rho(dot)=0. Hence it's a constant. A 'cosmological constant'. Perhaps I don't understand the question?" I found that answer in the GR Forum. Why did you repost the question here before responding to it there?