Sabine
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Coming up on August 6
🕑 Added 2022-08-03 13:41:13 +0000 UTCTwo months ago, I read several papers about counterfactual quantum computation and thought to myself: This is SO cool, why aren't there any good video about it? Well, I figured that out when I was trying to explain myself how you can compute with a computer that doesn't compute. But eventually, I think I found a way to get it across with lines and dots and it'll run on Saturday. I hope you'll let me know if it made any sense to you!
Comments
Still so much better than my blog...
Terry Bollinger
Hmm. After loading all comments, I am powerfully reminded why I (usually) don't make comments on Patreon anymore.
Terry Bollinger
Ah... as I already suspected, this is a variant of a particle "seeing" a path it never took, elaborated into a computation. That's not quite true: The matter forming those alternate paths must shift frames slightly due to action-reaction to the found particle. The shifts should even be testable with sufficiently small versions of the setup. (I wonder if that's ever been done? Seems plausible since microcavity stuff, even good ol' quantum dots, is in the same general bailiwick. But has anyone _specifically_ looked for whether "unused" paths of an extremely tiny apparatus experience rebound accelerations upon particle detection? The rebound effects should be detectable at that scale.) In any case, linear momentum doesn't quantize like angular momentum but is just as fiercely conserved. That means you can use mirror tricks to encode interesting complexity into relatively low-mass wave functions, and that in turn presents at least the prospect of useful computation. It's always a resolution issue, though: Low mass, easy setup, lousy resolution; high mass, difficult setup due to coherency loss, but good resolution. Nothing's ever completely free, but often, clever paths are available with sufficiently close examination.
