What would happen if all the energy conditions would be broken?

Question

Some models of phantom dark energy break all energy conditions (like the null energy condition but also others like the dominant energy condition).

Assuming for an instant that this would be actually possible, what would happen to the laws of physics as we know them? Would they break? Would they change? Would the fundamentals symmetries of nature underlying the laws of physics break?

Also, sometimes it's said that such a model would have an unbounded hamiltonian (from below). This would mean that the vacuum could be unstable and would allow for an arbitrarily strong vacuum phase transition or vacuum decay. Assuming for a moment that this would be possible, how would this affect the laws of physics as well? Would they (and their symmetries) also break?

Answer 1

From the perspective of general relativity, the absence of any energy condition would mean that any metric is a solution of the Einstein equations: Just compute the Einstein tensor for your favourite metric and declare that to be the nergy-momentum tensor of your (possibly weird) matter.

(This is discussed on p. 117 of Carroll's lecture notes, https://arxiv.org/abs/gr-qc/9712019 .)