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Experiments spell doom for physical-collapse explanation of quantum weirdness

quantamagazine.org

231–240 of 306 posts

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#233
post #9

Earlier quoted context omitted.

Disproving some form of measurable wave function does not provide evidence for MWI, which is unmeasurable and untestable nearly by definition.

Only if you assert that the other worlds are in some way "real". See https://en.wikipedia.org/wiki/Many-worlds_interpretation#Deb... The MWI is a simpler theory than other interpretations because it does not require "collapse" to be a physical process. The "realness" of the other worlds is untestable, but also not part of the theory. "unreal" MWI should be the null hypothesis given what we know to be true about quant…

Believers in Everett may not end up being right. But believers in Copenhagen aren't more right than believers in Everett. In fact, they "aren't even wrong" either, because they refuse to even engage with the question. So I think it's like the situation with democracy. You have to go with Everett until you find something better, providing you want to be scientific at all.

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#234
post #92
post #4

There is an often-repeated statement that different quantum mechanical theories are equivalent. This is an over-simplification. Is wave function collapse is a real thing or just an approximation of what happens when a large system is entangled? Some smart people have tried to make theories where wave function collapse is a real thing. These new experiments are working to rule out those ideas. My feeling is that Evere…

That's right: the "collapse" interpretation is an approximation. You can derive if from the MWI. We already know that the "worlds" separate and almost completely cease interacting. The interactions decrease to the order of "two to the power of Avogadro's number" almost immediately. The collapse interpretation rounds that to zero (at some arbitrary point). To make that more concrete you have to add a term to the equat…

If other 'branches' are still detectable, then they're probably detectable by more than one means; say, gravitationally. Could this be an explanation of dark matter? That is, dark matter is the sum of tiny gravitational interactions between many mostly-split branches of the wave function.

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#235

This article is a perfect example how science is getting led into dark areas by people who didn't learn quantum mechanics right or people who pretend to understand it, but can only blindly follow the formalism without much understanding of what they actually do. Every such article continuous to mysticize the whole subject by quoting famous scientists who were either puzzled by it at the time or scientists like John v…

For anyone preferring to read latex, I invite you to my [blog](https://wordpress.com/post/masteranza.wordpress.com/1135).

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#236
The results of these experiments indirectly tell us something about our chances of ever meeting aliens:

* No physical collapse => Everett interpretation AKA "many worlds"

* Many worlds gives us the Anthropic Principle for free

* The Anthropic Principle explains the origin of the first living organism, or, to put it another way, the observed existence of the origin of our first living ancestor does _not_ set any lower bound on the probability of the first living organism developing from non-living molecules.

* A very low probability of the origin of life implies the non-existence of any other life in the observable universe.

* Therefore, no aliens.

(The aliens do of course exist in other parts of the total Universal Wave Function, but we never get to meet them.)

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#237
It should be noted that the Everett many worlds model is impossible due to the nonlinearity of gravity - different worlds cannot exist independently of each other without interacting gravitationally - you’d get the kind of collapse that Penrose’s theory predicted. Given these experiments, there isn’t any obvious theory that squares the kind of wavefunction collapse we observe with the nonlinearity of gravity.

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#238
post #4

There is an often-repeated statement that different quantum mechanical theories are equivalent. This is an over-simplification. Is wave function collapse is a real thing or just an approximation of what happens when a large system is entangled? Some smart people have tried to make theories where wave function collapse is a real thing. These new experiments are working to rule out those ideas. My feeling is that Evere…

That oft repeated statement is really a lie except inasmuch as much as all interpretations / theories are intended to be compatible with reality as we observe it (and thus yield equivalent predictions to classical quantum mechanics for everyday quantum experiments).

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#239

Earlier quoted context omitted.

Check out "superdeterminism," first proposed by Bell (of Bell's inequality fame) himself and currently being vigorously pursued by Sabina Hossenfelder. There is no "collapse" per se according to this model and everything is really classical with hidden variables, and the entanglement comes because everything shared the same origin (the big bang). A very fascinating and in my opinion the best explanation, though it's…

> though it's extremely controversial and taboo because of its implications on free will Uhh, no. Essentially all existing physical theories are devastating for any non-compatabilist account of free will.

I get the impression that physicists who advocate “superdeterminism” are ignorant of the philosophical literature on “determinism” - because from a philosophical viewpoint, there is nothing “super-“ about their position, it is just plain old “determinism”.

Re: Experiments spell doom for physical-collapse explanation of quantum weirdness

#240

Earlier quoted context omitted.

Could the other branches be our dark matter?

No. They don't behave at all like dark matter. Among other things, there's no reason for them to be distributed in a halo, nor for some galaxies to lack them.

There's no reason for any dark matter to be distributed in a halo. Maybe it makes some math work better for the observations but nobody offers a dynamical explanation of how it would come to be a halo.
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