- #1
"Don't panic!"
- 601
- 8
As far as I understand it gravity is sensitive to absolute energies, as seen directly through Einstein's equation [tex]G_{\mu\nu}=8\pi GT_{\mu\nu}[/tex] Thus the local geometry of spacetime is directly affected by the local energy density (and not just differences in energy).
So whenever gravity is taken into consideration we must include all energy contributions.
What confuses me though is, if what I've said above is correct why is it that in Minkowski (flat) spacetime only energy differences matter? In particular, why is it possible to neglect the vacuum energy in QFT and instead just measure energy differences relative to it?
So whenever gravity is taken into consideration we must include all energy contributions.
What confuses me though is, if what I've said above is correct why is it that in Minkowski (flat) spacetime only energy differences matter? In particular, why is it possible to neglect the vacuum energy in QFT and instead just measure energy differences relative to it?