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Experiments spell doom for physical-collapse explanation of quantum weirdness

quantamagazine.org

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

#41

Post by im3w1l »

criddell wrote: post #24
dzdt wrote: 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…

> My feeling is that Everett's "many worlds" interpretation is the clear favorite But what are the worlds? My feeling is that Max Tegmark has it right. Everything is mathematics.

We can detect their presence because they cause interference with our own.

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

#42

Post by iainmerrick »

spywaregorilla wrote: post #38
iainmerrick wrote: post #34

Earlier quoted context omitted.

Is that really so weird? That's a very common version of time travel in SF, perhaps the most common. You can travel back in time, and you think you're changing history, but through a series of unlikely coincidences you end up being the person who created the history you were trying to change. Come to think of it, maybe that's more common in short stories, where the "gotcha!" format works. It's probably harder to spin…

It's not weird. It's fun. But it's stupid as a serious time travel proposal. Things like "travel in back in time 5 seconds unless you see your future self is already there" create a hard paradox that this logic cannot solve. Time loops are easily broken by anyone interested in testing them.

You sound as confident as the protagonist of many a time travel short story!

Edit to add: your comment reminded me specifically of a Ted Chiang story, "What's Expected Of Us": https://www.nature.com/articles/436150a

I found that link via a blog post that excoriates it for its supposed logical fallacies: https://loopingworld.com/2019/07/13/debunking-ted-chiang-rec.... I don't necessarily agree or disagree with that, but I do disagree that it's "obviously" logically wrong or inconsistent.

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

#43

Post by JackFr »

snowwrestler wrote: post #28
Comevius wrote: post #21

Earlier quoted context omitted.

No interpretation of quantum physics proposed by scientists ever required a conscious observer, that's more of a misinterpretation of what an observer is. It's an interaction, not a person or animal. As for the theory of consciousness, of course we are not special, it's information-processing, and it looks like thermodynamics is responsible for the emergence of information-processing structures. https://arxiv.org/abs…

A mental trick that helped me understand the concept of “an observer” in particle physics is to imagine it like playing billiards in a pitch black room. In normal human-scale billiards, there are immense numbers of photons flying around bouncing off everything. The photon interactions are far too small to affect the path of a moving billiard ball, but we can detect them easily with our eyes. So we can use photons to…

I know all analogies are imperfect, but that is a really great one. It really captures the problem of observing so elegantly.

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

#44

Post by resoluteteeth »

vpfaulkner wrote: post #36

From a layman’s point of view, it seems like we grasping at straws when it comes to these thorny quantum questions. Is fair to say, for example, that we are about as clueless as our ancestors were with the bubonic plague? To a non-expert it can be difficult to separate which theories lay on solid ground and which theories are highly speculative.

> From a layman’s point of view, it seems like we grasping at straws when it comes to these thorny quantum questions. Is fair to say, for example, that we are about as clueless as our ancestors were with the bubonic plague?

> To a non-expert it can be difficult to separate which theories lay on solid ground and which theories are highly speculative.

Sure, but isn't that the point of doing these experiments?

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

#45

Post by ravi-delia »

vpfaulkner wrote: post #36

From a layman’s point of view, it seems like we grasping at straws when it comes to these thorny quantum questions. Is fair to say, for example, that we are about as clueless as our ancestors were with the bubonic plague? To a non-expert it can be difficult to separate which theories lay on solid ground and which theories are highly speculative.

That would not be fair, though it's understandable why a layman might feel that way. The fact is, most physicists don't particularly feel the need to have an explanation for that kind of thing. We have the math, and most people agree on how to use it to make very accurate predictions. Collapse was always a little silly, but there are other possibilities as to why you'd get that kind of effect just from wavefunctions.

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

#46

Post by spywaregorilla »

iainmerrick wrote: post #42
spywaregorilla wrote: post #38

Earlier quoted context omitted.

It's not weird. It's fun. But it's stupid as a serious time travel proposal. Things like "travel in back in time 5 seconds unless you see your future self is already there" create a hard paradox that this logic cannot solve. Time loops are easily broken by anyone interested in testing them.

You sound as confident as the protagonist of many a time travel short story! Edit to add: your comment reminded me specifically of a Ted Chiang story, "What's Expected Of Us": https://www.nature.com/articles/436150a I found that link via a blog post that excoriates it for its supposed logical fallacies: https://loopingworld.com/2019/07/13/debunking-ted-chiang-rec... . I don't necessarily agree or disagree with that,…

It's really just on them for trying to alter the future in large ways before conducting small experiments to understand the mechanics of the universe imo.

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

#47

Post by ravi-delia »

rubidium wrote: post #35
dzdt wrote: 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…

Many worlds is just some peoples favorite because they get too weirded out but indeterminism. They prefer a billiard ball universe and so invented the hairbrained many worlds theory.

Or- and hear me out with this one- they prefer an explanation which follows naturally from existing experiments and doesn't require a hacked together non-linear irreversible operation which occurs only under bizarre conditions exactly when needed to patch over experimental results. No one in the whole world cares if the universe is deterministic or not, but collapse is embedded in an entirely deterministic system. MWI may not be right, but collapse is wrong.

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

#48

Post by lebuffon »

Don't tell anyone, but in the back of my mind I wonder if what we call quantum mechanics has something to do with the rendering engine in this simulation we find ourselves in.

Is quantum collapse just us "catching" the engine deciding what to render when we observe something? :-)

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

#49

Post by cb321 »

bowsamic wrote: post #8
im3w1l wrote: post #5

In true collapse-of-the-gaps style, what if collapse happens when an entangled system becomes so large that the edges of it are outside of each others event horizons due to cosmic inflation?

I think you mean expansion rather than inflation (inflation is something that happened very briefly at the beginning of the universe). In models with collapse, the collapse happens instantaneously, no matter what

As with any unsettled questions there are pros & cons to the various takes on quantum reality. Part of the appeal of MWI (intrication of observer into observed system as part of the measurement process) to me was always that the instantaneousness you mention here is a very "ordinary" kind of "fastness by synchronization". It's basically just a kind of causal wavefront hitting.

There are plenty of "infinitely fast" synchronization effects like this..some perhaps less obvious than others, but many pretty pedestrian and accessible to lay people. Neither the junction of a scissors or the "spot light" on clouds need be constrained by light speed, for example. People routinely abuse "nothing" (or maybe "go") in the " 'nothing' can 'go' faster than light" saying. :-)

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

#50

Post by Dx5IQ »

snowwrestler wrote: post #28
Comevius wrote: post #21

Earlier quoted context omitted.

No interpretation of quantum physics proposed by scientists ever required a conscious observer, that's more of a misinterpretation of what an observer is. It's an interaction, not a person or animal. As for the theory of consciousness, of course we are not special, it's information-processing, and it looks like thermodynamics is responsible for the emergence of information-processing structures. https://arxiv.org/abs…

A mental trick that helped me understand the concept of “an observer” in particle physics is to imagine it like playing billiards in a pitch black room. In normal human-scale billiards, there are immense numbers of photons flying around bouncing off everything. The photon interactions are far too small to affect the path of a moving billiard ball, but we can detect them easily with our eyes. So we can use photons to…

Observer effect while applicable is distinct from Quantum Weirdness aka Heisenberg Uncertainty
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