I’ve Only Seen One
Thanks to Jack Krupansky for asking the question in the title of this article.
It’s a good question. Personally, I can only remember seeing one: Google’s 53-qubit “quantum supremacy” experiment, and that algorithm has no practical use. Off the top of my head, I also don’t remember if the paper showed the entire 53x20 circuit, or if it was just shown in digestible chunks. Either way, what follows are some of the reasons why you don’t see 40+ qubit quantum algorithms out there.
I’ve Got Five
The most qubits I’ve ever had access to is 15. Believe me, I used them all. Currently, I only have access to five. And, although the IBM simulator allows up to 32, that’s more in principle than in practice; simulating larger numbers of qubits easily results in runtime errors. So, problem number one is that the vast majority of developers probably don’t have access to 40 qubits.
I’m Paying For This
If you do have access to 40+ qubits, an organization is presumably paying for it. All algorithms and their results are, therefore, intellectual property. There is one that I asked about recently that is either patent pending or already protected. So, another problem is that many of these algorithms are not meant to be shared.
