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And: > Around this same time I became aware of the problem of observation in quantum mechanics. At it’s basic level the issue is that you can affect particles
by northwest 13y ago
And:
> Around this same time I became aware of the problem of observation in quantum mechanics. At it’s basic level the issue is that you can affect particles by simply observing them.
That's simply because you can only measure by adding energy to the system, which obviously changes the state of the system.
- DennisP 13y agoThat makes it sound like a straightforward classical effect. It's weirder than that. In the two-slit experiment, if you measure which slit a photon (or other small particle) passes through, then after a bunch of particles you get two spots on the wall. If you don't measure, you get an interference pattern, as if the particle were a wave that passed through both slits. This is true even if you make the decision about whether to measure, after the particle has already passed through the slit. Check the measurement after the particle passes the slit, but before it hits the wall, and the interference pattern goes away.