Two loop corrections

1. Dec 16, 2007

romeo6

I have been reading a Weinberg paper (the cosmological constant problem), where he writes

"...Zeldovich assumed that these were cancelled leaving only the higher order effects: in particulal, the gravitational force between the particles in the vacuum fluctuations. (In Feynman diagram terms, this corresponds to throwing away te one-loop graphs, but keeping those with two loops"

Can someone help me understand this. I thought QFT said nothing about gravity. Why do the two loops correspond to the gravitational force??

2. Dec 18, 2007

romeo6

anyone??

:)

3. Dec 18, 2007

Gokul43201

Staff Emeritus
You might have better luck if you cite the paper.