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Lapidus
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Around time 33:40 min in this video, Prof. Paul Steinhardt says the following about gravity:
This argument is often brought forward, as in this case here, when inflationary cosmology is explained. The energy of the inflating universe comes from gravity or energy of the inflating universe is conserved since the energy of the inflation field is set off by the energy of gravity.
I also know from introductory QFT courses that gravity is special. When computing the vacuum energy, it is pointed out that for gravity not the potential energy difference but the total potential energy matters.
1. But where do I find this "bottomless feature" of gravity in the gravity and GR textbooks? Which chapter or formula in, say, Sean Carroll or in Bernard Schutz book explains it?
2. What makes gravity "bottomless"? Why does the same explanation does not apply for two opposite electric charges brought arbitrarly close to one another?
thank you in advance
There is something special about gravity that we all should have learned school, but never did. It is a very basic fact, which is that all the other energies we know have a bottom to them. If you draw the energy down, you eventually hit zero or a minimum where you can't get go below it. It is not true for gravity. Gravity is a unique form of energy which is bottomless.(...) The gravity potential curve goes to negative infinity when two objects are brought arbitrarly close to one another.
This argument is often brought forward, as in this case here, when inflationary cosmology is explained. The energy of the inflating universe comes from gravity or energy of the inflating universe is conserved since the energy of the inflation field is set off by the energy of gravity.
I also know from introductory QFT courses that gravity is special. When computing the vacuum energy, it is pointed out that for gravity not the potential energy difference but the total potential energy matters.
1. But where do I find this "bottomless feature" of gravity in the gravity and GR textbooks? Which chapter or formula in, say, Sean Carroll or in Bernard Schutz book explains it?
2. What makes gravity "bottomless"? Why does the same explanation does not apply for two opposite electric charges brought arbitrarly close to one another?
thank you in advance