Oh come on, it looks like an interesting take on standard existing theory. Once you accept the idea of the universe originating from a microscopic fluctuation 13.7 billion years ago, why should you be so sure that there is only one of them? And what exactly do you want “proved” when the paper itself (p.10) seems to say that under the authors’ model, the wormhole theory has just exp(-2.9)=around 5% chance of being the right explanation vs the more conventional one?

Authors: we calculate that proposition X has 5% chance of being true

Internet smartypants: oh yeah? Prove that X is true, hur hur.

Penrose (physics Nobel 2020) and someone had a sort of similar theory that some mysterious circles in CMB data were emanations from another universe, and it was taken seriously until the circles turned out to be from some problem with the measurement equipment. So your dismissiveness towards the idea says more about you than about the idea.

Me, I think this stuff is pretty cool and I wish I understood enough GR to read that paper. Leaving aside the whole topic of science (the study of actual natural reality) and treating it as a problem of pure math (finding equations that match a particular set of criteria without worrying about whether they describe something that actually exists), from what I can tell, it’s still a tough problem. But these kinds of ideas (wormholes, parallel universes, etc.) have been around for a long time, and the math works as far as anyone can tell. That’s the best you can hope for given that there’s no way to observe the big bang directly.