Buterin was briefly involved with people trying to efficiently simulate quantum computers (https://twitter.com/VitalikButerin/status/106215696645222809...).

I don't know much about the details of this particular attempt , but the strategy is not ridiculous on its face. Very implausible, yes, but it contradicts no theorem nor any established law of physics. Mostly, it's implausible because many people have tried very hard to find efficient classical simulations of quantum computers and all have failed.

From what I've seen, it's true, but Ethereum launched when Vitalik was 19 and his quantum silliness was years before that. Personally I'm glad nobody's looking at the stupid things I was thinking about at that age.

Not sure how reliable you might consider this source, but here's some information: https://medium.com/@tradertimm/vitaliks-quantum-conundrum-34...