I think https://xkcd.com/678/ is relavent.

Basically we are far enough out from "useful" QC that its anyone's guess (except for the people trying to convince you to invest in their startup). That said relavent metrics include number of qubits and their error rate (once you get past a certain number with a low enough error rate you can start to use error correction which is when things really start to become interesting)

It does depend a bit on what you mean by "useful" though see also https://en.wikipedia.org/wiki/Noisy_intermediate-scale_quant...

Good job commenting on something you know nothing about...

If you think i said something incorrect or misleading, by all means feel free to correct the record.

Yes, QC is far enough that it's "anyone's guess", but the field is actively working on sliding the answer to this problem from "anyone's guess" to "a bit more certain". It will never be 100% certain until the useful QC appears but we can decrease the probability of our predictions being pure guesswork. As an example, DARPA is funding a project to find the first high impact QC applications https://www.darpa.mil/work-with-us/publications-highlighting... along with finding when the first hardware to run those applications can be built https://www.darpa.mil/work-with-us/quantum-benchmarking-init....

QC startups should be funded because industry is a crucial component of QC progress and large-scale QC labs (Google, IBM e.t.c) can't work on all the ideas. The ideas that come from startups do accelerate QC development.

QCs are in all major data centers already. Although there is not much you can do with them, but you can use them. IONQ is considered the leader right now in QC. Look them up, very interesting stuff they are doing. They just partnered with astrazeneca to start developing useful applications. They will also demonstrate hybrid algorithms next week where they offload some stuff to QPUs to speed up models. I would say within two years QCs will start being useful.

> QCs are in all major data centers already

Citation needed

You can track resource estimates for different problems against QC performance here: https://metriq.info/progress

It crowdsources new submissions to the chart if there are ones you see missing (just open a PR)

i think there was some time ago a comparison with Commodore 64.