Well, they explained it a couple of paragraphs later. The previous record, a 45-bit quantum simulation, took 500 Terabytes of memory. I assume there's some sor

Well, they explained it a couple of paragraphs later. The previous record, a 45-bit quantum simulation, took 500 Terabytes of memory. I assume there's some sort of terrible exponential increase that would have made 49-bit simulations require four orders of magnitude more, or something impractical. But this one did 56 bits with just 4.5 terabytes of memory. All seems pretty clear.