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comment Negative energy/mass bounds on de-Sitter spacetime
Another thing: "energy in cosmology is not conserved" is an statement that is true both on de-Sitter and Anti-de-Sitter cosmologies, but the lack of the energy-positiveness-theorem is specific to de-Sitter spaces, so I hope that you see that the former does not by itself explain the latter
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comment Negative energy/mass bounds on de-Sitter spacetime
but energy conservation as a constraint is a completely independent constraint on the system than energy positivity: energy conservation for non-gravitational fields is just the divergencelessness of $T_{\mu \nu}$, but energy positivity is about quantum inequalities and energy conditions.
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comment Negative energy/mass bounds on de-Sitter spacetime
"the total conserved energy can't be well-defined in our (nearly) de Sitter space" I'm not wondering about energy conservation, What I'm wondering is negative mass concentrations as would be expected if the positive-energy theorem does not hold. You seem to be conflating the issue of energy-conservation in GR (which as you rightly said, the lack of a Killing time vector means that it is absent) with that of negative energy. Why are both issues related?
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accepted Negative energy/mass bounds on de-Sitter spacetime
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comment Negative energy/mass bounds on de-Sitter spacetime
but I thought that was what the lack of a positivity theorem was implying: since our universe is de-Sitter, there is no such thing as a 'theorem' that forbids them. At least not a known one yet. Or is there some complementary non-negativeness theorem beyond the one being discussed here? You mention that it is forbidden because the vacuum "obviously" doesn't collapse and we are here :-) so, are you saying that the reason negative energy is not seen is purely anthropic?
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comment Negative energy/mass bounds on de-Sitter spacetime
thanks. What would you say that is the reason we haven't seen/detected negative energy/mass yet? Is it forbidden by some quantum/stringy symmetry? It is just a symmetry-breaking thing that could change if temperature gets to inflationary-epoch levels? Or maybe negative mass is composed of sterile/dark energy that doesn't interact with our sector?
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comment Negative energy/mass bounds on de-Sitter spacetime
thanks, that paper was the one that brought the question in my head in the first place :-)
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comment On the coordinate independence of general relativity
That hole argument still confuses the bejeezus out of me
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