Re: "To model just a few hundred electrons needs a computer bigger than the universe"
Actually it needs a computer which is exactly the same size as the universe. The universe is, existentially, an exact simulation of itself. That doesn't mean the paper is wrong. Those electrons don't exist in isolation; because of entanglement, it's quite artificial to separate them from the rest of the Universe, and if you do so, you're going to have simulate the effect of the rest of the Universe on them... so you're going to have to simulate the whole Universe anyway, which of course needs a simulator that contains more bits than the whole Universe, even if it's a quantum computer, and even if quantum theory is the true theory.
All we can ever simulate, even in principle, is an approximation.
Biting the hand that feeds IT
