Yeah to be clear, this isn't "quantum advantage" because there's no real world value (as much as IBM claims there is). At best this is what a lot of people refer to as "weak quantum supremacy" since there's no super-polynomial separation to be had here.
This post goes into a taxonomy for different quantum computing milestones in case anyone's interested: https://medium.com/@wjzeng/clarifying-quantum-supremacy-better-terms-for-milestones-in-quantum-computation-d15ccb53954f
> Our demonstration includes the study of the simplest function that cannot be computed classically in the one-bit limited space model: finding the majority of three bits (that is, returning zero if more than half of the bits are zero, and returning one if more than half of the bits are one).
000 -> 0
perm of 001 -> 0
perm of 011 -> 1
111 -> 1
> we explored what we call the limited space computations. These are circuits restricted to using two-input gates, and limited to using one bit of computational/scrap space. This restriction allows us to establish a fair comparison between the power of classical and quantum computational space, and in particular demonstrate a fundamental advantage of computing with qubits over classical bits.
A fair comparison. In which we compare two pack mules. One has one slot, either empty, or filled. The other has two, empty or filled. This is fundamentally comparing equal numbers of dice to coins. Of course the die is going to provide more information.
> our (noisy) limited-space quantum computer demonstrated a success rate of 93 percent, still beating the limited-space classical computer.
> the classical computer can only succeed 87.5 percent of the time whereas a perfect, noiseless quantum computer could succeed 100 percent of the time.
It should be noted that this "noiseless" computer would be where the technology is good enough to get clear readings 100% of the time. Bits are the classical's noisy version. Our technology has advanced to where the accurate reading of voltage from the same hardware is 0/1/2/3/4 instead of 0/1. In other words, there is a good chance a 'modernist' computer could match the quantum one, and we don't have to wait for the ability to 'cut the noise'. But quantum will become a buzz-word, and that won't happen.
An actual 'real world' use case would be generating prime numbers, where quantum machines might really outshine classical machines.
https://research.ibm.com/blog/quantum-advantage-limited-space#fn-1
4 comments
12 u/None 02 Jul 2021 17:42
6 u/imarc 02 Jul 2021 19:08
2 u/1ethanhansen 02 Jul 2021 20:44
4 u/None 02 Jul 2021 20:24