A very nice explainer why "if you're so worried about quantum computers, why haven't they factored 21 yet?" isn't a very convincing argument. Look at the labels of the graph, and how extremely close the various lines are for factoring 21 and 2048 bit numbers. Polynomial scaling remains polynomial, unfortunately, and by the time you can factor 21 you're almost ready to break RSA.

https://bas.westerbaan.name/notes/2026/04/02/factoring.html

Factoring is not a good benchmark to track Q-day

Homepage of dr. Bas Westerbaan, principal research engineer at Cloudflare, working on making the Internet post-quantum secure

@sophieschmieg A physicist I used to work for said quantum computing is very good right now for getting grant money to develop very nice ADC's and detector circuitry, which is useful for astronomy and particle physics.

He admitted when I pressed him that he agrees that the actual computing part is complete bunk and going nowhere.

@poleguy @sophieschmieg @cstross ding ding ding! 'Quantum computing' is full of the same kind of lunacy as LLMs; "it's inevitable, it's the future, ignore hitting obvious dead-ends." I would say that given the current landscape, effective communication by quantum teleportation over long distances is more likely to happen first despite the LLM-fanboy VCs shoveling money as fast as they possibly can.
@poleguy @sophieschmieg @cstross and yes, quantum teleportation is absolutely real, empirically proven, and Urbana-Champaign achieved a *94%* fidelity with indium-gallium-phosphide last year. Meaning we are getting very close to "it's a scale manufacturing problem."