I can see why it might look like that from the outside, but the set of mathematical results that led up to it actually come from the angle of, “let’s try to pro

I can see why it might look like that from the outside, but the set of mathematical results that led up to it actually come from the angle of, “let’s try to prove that traversable wormholes and the negative energy densities required to create them are impossible.” In trying to prove that, you learn a lot of interesting things along the way: 1. Negative energy densities are a universal prediction of all quantum field theories, and therefore are not as outrageous to think about as one might naively believe. [0] 2. The amount of negative energy density permitted by quantum field theory is NOT enough to support traversable wormholes, as long as you make some mild assumptions about the behavior of spacetime. [1] 3. Those mild assumptions seem NOT to be required by string theory, and string theory supports some solutions with traversable wormholes. [2] 4. Those solutions of string theory appear to be self consistent in an unusual and novel way, which is why string theorists like Juan Maldacena find them interesting. [3] Every step is all super nontrivial and tells us something new about the mathematics of spacetime. Of course they’re models, maybe they all rest on some faulty assumption about nature that will later turn out to be wrong. So the final pillar of the story, the one that’s hard to communicate without spending years of your life studying it, is that every remaining assumptions about quantum gravity that goes into these arguments appear to be impossible to get rid of without having horrible consequences where spacetime can’t become smooth or relativistic at large scales. So these models are at least very plausible even though the ultimate truth will have to come from experiments. [0] Proof appears many places, I like the one in arxiv:1803.04993 on page 11 [1] arxiv:1010.5513 [2] arxiv:1608.05687 [3] the paper linked by OP :)