Hi Jasmine, we usually think of QA in a narrower sense: Taking a sufficiently detailed snapshot of a small region of spacetime, as small as a person’s brain at a previous time.

What you have in mind is cosmic QA on steroids: Taking a perfect snapshot of the whole universe at a previous time.

It can be argued that nature already does that, spontaneously: Other times are but special cases of other Everett worlds.

If you take a cosmic snapshot and run it on a computer able to run an entire universe (a problematic notion with its own issues), there is no self-referencing problem, because the copy universe would run in a universe that is not the same universe from which the snapshot was taken.

As you say, natural laws are not strictly deterministic (quantum and chaos). So the copy universe would soon diverge from the post-snapshot history of the universe from which the snapshot was taken.

But what’s wrong with that? Instead of reliving an identical version of my life, I would prefer some changes, exploring slightly different possibilities…