They are currently targeting more material science, such as quantum chemistry for drugs discovery or new material discovery. They can’t and do not aim to do prime factorization on those.
Currently the two qubit gate error rate is listed as ~2.7e-3 (see https://quantum.cloud.ibm.com/computers?system=ibm_phoenix but note it will vary from day to day). That implies you can expect ~400 entangling gates before experiencing an error. A zero-shenanigans factoring of 21 takes ~2000 entangling gates. So it's not good enough to factor 21 in any meaningful sense.
Really what matters about this chip is that it is better suited for error correction. They have a square grid connectivity (previous IBM chips incurred fatal overheads from their heavy hex connectivity), they can actually reset their qubits now (previous IBM chips couldn't scale to long running computations because once leakage arose nothing could remove it except waiting a long time), and they have tunable couplers instead of fixed frequency ones (previous IBM chips were just doomed whenever some problem happened to land on their operating area in frequency space).
Most interesting quantum computations take millions or billions of gates. Factoring classically intractable numbers takes tens of billions of gates. No one is going to do that many quantum gates without error correction. Whenever a quantum computing company says anything other than "it made error correction better" or "it will make error correction better", you can ignore that. It's just some side quest. Maybe it's interesting in and of itself, but it's not what matters for progress.
FWIW, Scott Aaronson has likened the question on factorization of concrete instances to what happened during the Manhattan Project:
Joe #11: Then you’ll be waiting a long time, because that’s a stupid metric. (Or rather: anyone willing to use that metric today, is probably someone you shouldn’t trust.) It’s almost exactly analogous to judging the Manhattan Project in 1942, 1943, 1944 by the metric “how big an explosion can you make, today?” I.e., it’s something that’s going to be basically flat for a long time and then undergo a step change, under the assumption that everything is progressing as it should—because you need a critical mass in the one case and to exceed the fault-tolerance threshold in the other.
I agree and I was being facetious since I know the answer is nothing much. The point is that IBM write all this breathless marketing copy that seems detached from the actual utility of the device.
Although I believe there's a difference with the Manhattan project. The original atom bomb was "useful" even at its small scale. Whereas there's likely to be a lot of time between a quantum computer that can factor 69 and a quantum computer that can factor RSA 2048.
IBM write all this breathless marketing copy that seems detached from the actual utility of the device
What are the actual utility according to IBM? Did they say you can order one today on their website? Or even "call us to get the pricing info"? Are there case studies of what their customers use it for? Or only potential uses?
Although I believe there's a difference with the Manhattan project. The original atom bomb was "useful" even at its small scale.
No it was not useful, otherwise it'd have been paraded and hyped up on the media. The trinity test was in July 1945. Hiroshima happened in August. They were practically used as soon as they were deemed ready. Hundreds of thousands people died.
Comments
What's the largest semiprime it can factor?
You can attempt 15 yourself if you want:
https://towardsdatascience.com/where-are-we-with-shors-algor...
If you run it over and over again you will eventually get 3 or 5...
They are currently targeting more material science, such as quantum chemistry for drugs discovery or new material discovery. They can’t and do not aim to do prime factorization on those.
Good
Currently the two qubit gate error rate is listed as ~2.7e-3 (see https://quantum.cloud.ibm.com/computers?system=ibm_phoenix but note it will vary from day to day). That implies you can expect ~400 entangling gates before experiencing an error. A zero-shenanigans factoring of 21 takes ~2000 entangling gates. So it's not good enough to factor 21 in any meaningful sense.
Really what matters about this chip is that it is better suited for error correction. They have a square grid connectivity (previous IBM chips incurred fatal overheads from their heavy hex connectivity), they can actually reset their qubits now (previous IBM chips couldn't scale to long running computations because once leakage arose nothing could remove it except waiting a long time), and they have tunable couplers instead of fixed frequency ones (previous IBM chips were just doomed whenever some problem happened to land on their operating area in frequency space).
Most interesting quantum computations take millions or billions of gates. Factoring classically intractable numbers takes tens of billions of gates. No one is going to do that many quantum gates without error correction. Whenever a quantum computing company says anything other than "it made error correction better" or "it will make error correction better", you can ignore that. It's just some side quest. Maybe it's interesting in and of itself, but it's not what matters for progress.
FWIW, Scott Aaronson has likened the question on factorization of concrete instances to what happened during the Manhattan Project:
https://scottaaronson.blog/?p=4121#comment-1804101
I agree and I was being facetious since I know the answer is nothing much. The point is that IBM write all this breathless marketing copy that seems detached from the actual utility of the device.
Although I believe there's a difference with the Manhattan project. The original atom bomb was "useful" even at its small scale. Whereas there's likely to be a lot of time between a quantum computer that can factor 69 and a quantum computer that can factor RSA 2048.
What are the actual utility according to IBM? Did they say you can order one today on their website? Or even "call us to get the pricing info"? Are there case studies of what their customers use it for? Or only potential uses?
No it was not useful, otherwise it'd have been paraded and hyped up on the media. The trinity test was in July 1945. Hiroshima happened in August. They were practically used as soon as they were deemed ready. Hundreds of thousands people died.