I say no, but this might get some interesting answers.
I know people rarely return to these questions but here is an amendment to the:

Suppose that you either imagine or conjecture the existence of some alternate universe and come reasonably close in that hypothesis, such that you could devise a reasonable ‘experiment’ to test for its existence; in so doing, would you not have ‘communicated’ sentience into that universe?

Paradoxically, you have proven that you cannot prove its [universe containing no sentience] existence or non-existence.

When one attributes ‘existence’ to some phenomenon, aren’t they really attributing ‘meaning’?