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Comment by EvaPeron | Hacker News Reader

This is exciting to me because it seems to make the Everett "Many Worlds" view inevitable, because if A) the wave function exists (which this article seems to indicate) and B) if it never collapses spontaneously (and 50 years of research into this would seem to say no it does not), then necessarily one gets "many worlds", i.e., a large number of co-existing universes inhabiting an N-dimensional Hilbert Space, or, to put it differently, there are worlds in which Schrodinger's cat lives, and ones where it does not.

All very cool, but I still am not planning to sign up for the quantum suicide experiment to test for quantum immortality just yet. ;)

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Only tangentially related, but I think it is very unfortunate that Everett's interpretation is called "Many Worlds". Talking about "Many Worlds" paints a picture of parallel universes that one can travel between. That makes no sense, and it is not what Everett says.

I was introduced to quantum mechanics from a TCS point of view, i.e. via quantum computing. After some time of getting used to the mathematics, it seemed quite natural to me to suppose that the universe "really is" a vector in a Hilbert space, without any spontaneous collapses, and so on. This actually caused me to reject the notion that there are "Many Worlds". After all, it's all just components of a single vector describing our universe. It's a single world that just happens to work according to rules that are unintuitive relative to our everyday experience (and the real mystery lies in how consciousness works, but that's a mystery even without QM).

So I was really surprised when I found out that what was meant by "Many Worlds" is almost exactly how I had interpreted things as well, and to this day it feels to me as if the name as an attempt to popularize this interpretation dilutes a proper understanding.

What do you mean by "never collapses spontaneously"? Researchers have been trying to prevent states from collapsing for decades and it's really hard.

Under the Many Worlds Interpretation, the observations we could explain in terms of waveform collapse are due to entanglement decoherence. The argument for Many Worlds is that since our observations can be explained[1] in terms of other well understood properties of quantum systems that we even have equations defining, there's no need for this "waveforms collapse" hypothesis that isn't even mathematically where we don't have any equations that tell us when it occurs.

The idea, if you're not familiar with it, is that when a photon hits a partial mirror part of the waveform goes one way and part goes another way. When scientists conduct an observation of the photon they become entangled with it, and similarly there are two sections to the scientist+photon waveform. But because the mass of the waveform is now really humongous, you aren't going to be able to observe quantum effects the way you do with a single photon.

[1] Except that alone doesn't tell us where Bode statistics come from.

What are Bode statistics?

The fact that the likelihood of you seeing your instruments report a particle in a given place is proportional to the square of the waveform's magnitude at that place.

Is that what it's called? I thought it was Jordan's rule.

Maybe you are talking about Born's Rule?

What I mean is it does not collapse "all by itself", rather, it needs environmental interference in order to "collapse" from the observer's point of view. In the view of the many-worlds theory, though, it never really collapses, only appears to from the observer point of view, due to environmental interference.

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