My question is about the apparent CPT violation of the observed universe, due to the imbalance of matter and antimatter, but first I have a motivating observation:
General relativity respects time reversal (T) symmetry. However, formation of black holes ostensibly spoil T symmetry, because a black hole cannot un-form. What preserves T symmetry in this case is that if you evolve the system which formed the black hole backwards in time, you get a white hole singularity, which is the time-reversal of the black hole. (We usually don't think about white holes because they aren't observed, presumably due to initial conditions of the universe.)
Now I wonder if something analogous can fix the observed CPT asymmetry: Is there a reasonable way in which antimatter could come to dominate at the end of the universe, as a CPT analog of the matter domination of the current "early" phase of the universe?