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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

#181

Post by kgwgk »

krohling wrote: post #175
TheOtherHobbes wrote: post #94

Earlier quoted context omitted.

I don't see how relabelling "collapse" to "separation" and adding more or less infinitely proliferating universes solves the problem. MWI also contradicts itself. Supposedly the universes are independent, but if their influence doesn't define the wave equation they do nothing to help explain it. It's a very strong and exceptional claim with absolutely no evidence to support it. "Feeling" isn't enough.

I don't believe "feeling" has anything to do with the MWI interpretation. At least I've never heard it described that way. Given the equations that describe quantum mechanics (ie Schrodinger equation) MWI is essentially the "null hypothesis". No equations that describe collapse have ever passed the rigor of experiment and all collapse theories require modifications to the mathematics of QM. The burden of proof here i…

> MWI is essentially the "null hypothesis"

Null hypothesis in the sense of not producing any predicition? /joking

I agree with the grand-parent that substituting a "collapse" that we cannot understand with a "separation" that we cannot understand doesn't seem a big step forward.

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

#182

Post by omnicognate »

Comevius wrote: post #3

Looking out for quantum consciousness in articles about quantum physics would be a good drinking game, though here it is handled with a proper amount of scepticism. The pressure is enormous for writers to include mumbo-jumbo, because people click on these articles expecting to find out that it's possible to alter the Universe with psyhic abilities, which is how quantum physics is represented in social media, especial…

Except that in this context it isn't mumbo-jumbo at all. It's a falsifiable theory proposed by one of the most distinguished mathematical physicists in the world, in the process of being falsified. Perfectly respectable, though highly speculative, science.

The article didn't include it for lulz and clicks. It's directly relevant.

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

#183

Post by licnep »

lebuffon wrote: post #48

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? :-)

I have very little knowledge of quantum physics, but in my mind there is some similarity between quantum phenomena and backward raytracing in computer graphics.

In forward raytracing, images are rendered by "shooting" photons from all lightsources and seeing which ones end up hitting the player's camera. This is similar to what we think happens in nature, but the calculation is extremely inefficient, because the vast majority of photons never hit the player's viewpoint.

In backward raytracing, we only shoot "photons" backwards from the player's camera, and see which rays end up hitting a light source. This computation is much more efficient.

It makes me wonder if our "simulation" uses a similar shortcut

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

#184

Post by lamontcg »

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.

> which theories are highly speculative.

So QM itself is on very, very solid ground. You're using it now on your computer.

The interpretations of QM and the attempts to reconcile the exceptionally well tested mathematics of QM and the reality that we experience which is not-QM at all are all philosophical with zero evidence. Everyone just tries to make compelling arguments based on things like Occam's razor about why their horse is the best one in the race without actually knowing anything at all.

We have place a few bounds around things like Bell's inequality so we know that local hidden variable theories are ruled out, but that is about it.

The title article is very interesting because its one of the first few actual tests to probe if there really is a transition between QM reality and classical reality. Regardless of who actually wins the horse-race the important thing here is that there's slow progress being made on trying to experimentally test theories. This is why I've always liked the Penrose models of collapse better than the MWI models since the former have some chance of being actually testable, while with MWI you just blindly decide it is true or not and then you argue a bunch about philosophy and never do any experiments, which isn't science. Penrose models of collapse might be wrong but at least they're in principle testable, which is incredibly exciting about this article.

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

#185

Post by fallingfrog »

lamontcg wrote: post #179
fallingfrog wrote: post #90

Earlier quoted context omitted.

Well, the thing is that the MWI is actually simpler than all the other interpretations, because it simply removes the idea of wave function collapse entirely. Any theory involving wave function collapse is adding something extra to quantum physics that can't be demonstrated experimentally. Because we live in the macro world, it feels like a single unitary reality is simpler, but actually, the MWI makes fewer assumpti…

> Any theory involving wave function collapse is adding something extra to quantum physics that can't be demonstrated experimentally. Title article is literally about trying to test those theories experimentally.

..And failing to find any evidence of collapse. Hence "can't be demonstrated". I didn't mean "can't be looked for" I meant that attempts to find it have not been successful.

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

#186

Post by lamontcg »

iainmerrick wrote: post #39

Falsification is hard work, and rarely reaches a tidy end point. Even now, according to Curceanu, Roger Penrose — who was awarded the 2020 Nobel Prize in Physics for his work on general relativity — is working on a version of the Diósi-Penrose model in which there’s no spontaneous radiation at all. It's incredible how influential Penrose has been for such a long time, and continues to be. As far as I can tell (I'm in…

Most scientists either blindly accept collapse as a mechanism and then happily use the highly accurate math and don't care it isn't testable, or if they think about it at all they adopt something untestable like MWI and then happily use the highly accurate math and don't care it isn't testable. Thinking hard about testable theories in this area is incredibly slow progress and doesn't pay a lot of bills (https://www.theguardian.com/science/2013/dec/06/peter-higgs-...)

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

#187

Post by sfink »

fallingfrog wrote: post #90
lupire wrote: 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.

Well, the thing is that the MWI is actually simpler than all the other interpretations, because it simply removes the idea of wave function collapse entirely. Any theory involving wave function collapse is adding something extra to quantum physics that can't be demonstrated experimentally. Because we live in the macro world, it feels like a single unitary reality is simpler, but actually, the MWI makes fewer assumpti…

Only to the extent that MWI is actually a position. My understanding of MWI is: shit happens, and there's no need to understand why specific shit happens because all shit "happens" (by a definition of "happens" that carries basically no meaning) and you should be happy just to prove that the shit that happens is among the full set of shit that could happen. It's the "don't worry your pretty little head over it" theory of reality.

Here's the best poem ever written, or that will ever be written:

    Roses are red
    Violets are blue
    MWI stinks
    And so do you.
Don't think it's that great? Well, that's because there exist other versions of me that wrote different words up there, and you just happened to read a version that wasn't that great.

I hereby accept my position as God Poet of the Universe.

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

#188

Post by GoblinSlayer »

tsimionescu wrote: post #98
ravi-delia wrote: post #47

Earlier quoted context omitted.

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. MW…

Actually, if you eliminate collapse entirely as a non-linear operation, then you have a new huge problem for QM: there is plenty of non-linearity in the universe (e.g. double pendulum experiments, not to mention GR), and QM predicts that there shouldn't be any non-linearity at all, if you eliminate wave function collapse/the Born postulate.

Hmm... is de Broglie wave linear? Trigonometric functions don't look very linear to me.

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

#189

Post by TEP_Kim_Il_Sung »

d_tr wrote: post #172
ryeights wrote: post #158

Earlier quoted context omitted.

Can you elaborate on this? The Wikipedia page for MWI says >The many-worlds interpretation implies that there are most likely an uncountably infinite number of universes. https://en.wikipedia.org/wiki/Many-worlds_interpretation

Not the parent, but I 'd say this amounts to how you define a "universe". There is a single wavefunction which says that one "copy" of you observes result A and another "copy" observes result B. Using the phrase "many universes" implies that these two scenarios are considered as "different universes". I personally do not like this phrase and find it misleading.

You are all the "copies", and, under certain conditions, can experience all their observations. Think of yourself more as an aspect of a multifaceted being experiencing the universe through you.

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

#190

Post by awinter-py »

ugh the actual news event being covered in this article is a 2022 result[1] confirming a 2020 result[2] both of which 'set a lower bound' on this theory by penrose. 'set a lower bound' means they didn't find it.

this article is credulous -- yes, this may exist and semi-serious people are looking for it, but pls don't confuse 'we haven't found it yet' with 'current science suggests this is very small'.

how small?! at least admit that your theory doesn't predict an energy level. 'Current science suggests that bigfoot dwells in the places we have not yet looked'. Also put the newest paper in the first paragraph, don't make me dig through recirc links, ugh.

1. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.12...

2. https://www.nature.com/articles/s41567-020-1008-4

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