For speculative fiction you generally want to choose something that has a low chance of being disproven before you can publish it. In general such drastic inventions of new physics are not seen as hard science fiction except in the rare cases where the author is actually a physicist or something but then they usually aren't going to speculate too wildly when they are know they almost certainly are going to be wrong. Soft sci-fi or hard magic fantasy usually fills that niche, the books have better longevity that way.

Not to pick on your hypothetical but you could easily have all the same effects by just digging a bit into materials science and/or condensed matter physics, even if you just stuck to things that we know are possible but are currently too difficult to manufacture at scale (or at all) you'd have plenty of new unique materials to build a compelling story around.