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Comment by yodegge | Hacker News Reader

This is one of the fundamental mysteries of quantum mechanics called the "observer effect". Experiments have proven that particles change their essence at the instant moment they are being observed. This discussion is not only philosophical, we can prove perception changes everything.

https://m.youtube.com/watch?v=ZH9OfoM1MiU

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That popsci video is — out of necessity, this is not a criticism of those in it — a massive oversimplification.

One of the arguments on this topic is if there even is an observer effect at all, with one alternative being that the quantum wave function never collapses, instead it is our own wave function becoming entangled with that of the particles we observe: the part of us which observes |A> is correlated with the part of the particle wave function in state |A>, the part of us which observes |B> with the part of the particle wave function in state |B>.

(And I'm also oversimplifying, because I’m still learning this stuff).

The one issue I have always had with the 'observer' problem is that everything is 'seen' by something. But then I am a dullard on this junk and probably have it wildly wrong :)

My (limited) understanding is that the problem you’re raising is exactly why quantum computers are difficult.

I think it’s something like: yes, everything is “seen” by the rest of the universe, but “seeing” is done with discreet did-or-didnt happen events (mostly photons) which can be suppressed.

We certainly cannot prove that perception changes everything. The greatest mistake physicists continue to make is using common words that mean particular things to refer to something utterly different. “Observer” is as fine an example as any. The resulting misinterpretations, even by physicists themselves, were completely avoidable without launching the quantum fluffery industry, but here we are and remain.

right, "observer" essentially means "interact with in any way that exchanges information, in the quantum sense of the word information"

Still though, the fact that some states remain indeterminate until that interaction takes place means the universe holds its cards pretty close.

The observer effect has nothing to do with observers, it's just that entangling with large systems decoheres small systems where you can observe quantum effects.

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