The Copernican Principle and the Waveform of Reality - A Copenhagen Bug

[Rap]

1. I have 50% probability A and 50% probability B. As separate entities, they may have definite polarizations H (if A) or V (if B). But if I recombine them, I restore a superposition. Yet that state cannot be constructed from an H or V individually. So the thing I am manipulating in each portion is not a photon in and of itself. It is a wave state.

When we all have access to the same information, we all agree on the wave function, and it appears to have an objective reality. Its only when two people have different information, and this is not the result of incomplete measurements by one or the other, that you need two different wave functions to encode knowledge. The only way I know to do this is to make one observer part of the system being observed by the second observer, as exemplified by Wigner's friend.

2. What's to explain? There is no experiment.

I don't understand - it is a thought experiment. Are you saying thought experiments are invalid? Are you saying that I did not explain it correctly or completely?

 

[DrChinese]

I don't understand - it is a thought experiment. Are you saying thought experiments are invalid? Are you saying that I did not explain it correctly or completely?

Well, it's a paradox so there is a faulty assumption. I wouldn't try to resolve that by reference to the reality of the wave function. And I don't pretend to be able to explain what collapse is. Is it physical and objective? I dunno, wish I did. All I can say is that the existence of interference effects, as well as the ability to reconstruct a superposition, leads me to conclude that the wave function has objective reality. And I would say that the experimental evidence supports this view.

 

[Rap]

Well, it's a paradox so there is a faulty assumption. I wouldn't try to resolve that by reference to the reality of the wave function.

I would - especially if it produced no further paradoxes, and every other attempt to resolve the paradox were unsatisfactory. It seems to me that almost every paradox in QM is resolved by rejecting the classical notion of objective reality, independent of measurement. And we can never measure the wave function, we can only infer it from measurements which involve the modulus of its amplitude.

 

[DrChinese]

It seems to me that almost every paradox in QM is resolved by rejecting the classical notion of objective reality, independent of measurement. ...

True enough, no argument from me on that. But to me the issue is: objective reality of what?

To me, the relationships of the HUP are objectively real while non-commuting particle observables are not. To me, conservation rules (and conserved quantities) are objectively real while their constituent components are not. So I tend to think of the wave function itself as physically real, and not just a tool. Of course, this may just be application of semantics to the phrase "objective physical reality" itself.

 

[Rap]

True enough, no argument from me on that. But to me the issue is: objective reality of what?

To me, the relationships of the HUP are objectively real while non-commuting particle observables are not. To me, conservation rules (and conserved quantities) are objectively real while their constituent components are not. So I tend to think of the wave function itself as physically real, and not just a tool. Of course, this may just be application of semantics to the phrase "objective physical reality" itself.

I would be interested in any thoughts you have on the resolution of the Wigner's friend paradox. An observer is put inside a box. Forget the cat, the observer is looking at a screen which registers a photon from a low-intensity source. When the box is closed, no photon has been observed. At time t>0 an outside observer now describes what is inside the box as an apparatus and observer in a superposition of photon-seen and photon-not-seen wave functions. To the observer inside, the wave function is either in a photon-seen state, or photon-not-seen state (collapsed).

 

[DrChinese]

I would be interested in any thoughts you have on the resolution of the Wigner's friend paradox. An observer is put inside a box. Forget the cat, the observer is looking at a screen which registers a photon from a low-intensity source. When the box is closed, no photon has been observed. At time t>0 an outside observer now describes what is inside the box as an apparatus and observer in a superposition of photon-seen and photon-not-seen wave functions. To the observer inside, the wave function is either in a photon-seen state, or photon-not-seen state (collapsed).

I doubt anything I say is going to answer much of anything on this. If Wigner's friend is in a superposition according to Wigner, then there cannot be a measurement by Wigner's friend that has now been collapsed. That's true no matter what the friend says.

Now I realize that the idea of the paradox is that the position of the observer leads each to report a different reality, and therefore reality cannot be objective. But I would still say that the result of an experiment should not contradict anything I said above.

 

[Mute]

Ah! That's where I started. We are back to the bug. It's bug eyes observe the photons from the distant star, but it's bug brain can't generate information about what it has observed. So the wave-function does not collapse. It is still just a probability of a star at that location.

Well, I could be wrong. Perhaps a tiny bug could collapse the wave-function of a star instantly 50,000 light years away without generating any information about what it has observed. That would be even more interesting, in my own humble opinion.

I'm just musing about the connection between the generation of information and the collapsing of the wave function. I didn't mean to disturb anyone. Carry on.

You seem to be confusing "information" with "meaning". Information, as discussed in a scientific context, is divorced from having "meaning". A binary sequence is a simple example - it's just ones and zeros, but it has information content that we can analyze. The "meaning" that the string has is something we impose on it; it is not a property of the string itself. When photons reach the bug's eyes information is generated: neurons are triggered to fire, spike pulses encoding more information are produced, etc. Whether or not the fly can attach any meaning to this information processing is a separate issue entirely. Quantum mechanics might have something to say about information, but it has nothing to say about the "meaning" of that information. The meaning is just what interpretation we decide to ascribe to the information that has been measured.

 

[Rap]

I doubt anything I say is going to answer much of anything on this. If Wigner's friend is in a superposition according to Wigner, then there cannot be a measurement by Wigner's friend that has now been collapsed. That's true no matter what the friend says.

I am having difficulty understanding what Wigner's friend experiences if your statement is true. If your statement is true, then Wigners friend is in an objectively real superposed state. What is that like?

 

[DrChinese]

I am having difficulty understanding what Wigner's friend experiences if your statement is true. If your statement is true, then Wigners friend is in an objectively real superposed state. What is that like?

Hmmm. I think it is very similar to the state in which it is approaching 5 o'clock.

 

[IllyaKuryakin]

I've carefully read and considered all the replies above and suggest the following resolution. We have very good experimental evidence that the Universe proceeds in a probabilistic fashion on the quantum scale of single particles. We also have excellent evidence that the Universe proceeds deterministically on the macro scale of anything we can see with the unaided eye. I offer GR as proof of this, as it has been experimentally tested to many decimal places in many ways, and no deviation of data indicates the probabilistic scattering we see in QM. So, let's accept that both are true, and the transition from QM behavior to deterministic occurs at some small level and we just don't know yet what physical laws govern that transition. There are many experimental physicists looking for that transition and the laws that govern it now, and just because we don't completely understand it now there is no reason to believe we never will. So, let's assume some day we will understand that transition, and all the physical laws that govern it. In that case, I have to reverse my earlier conclusion and say, I agree, if a tree falls in the woods, and no one observes it, it's just a tree that fell deterministically, and it made a sound whether anyone observed it or not. So, logic holds and all is well with the Universe, Yes? No, not yet.

We come to the strange action at a distance, and the odd observations that seem to indicate that a photon knows whether we are observing it or not. Perhaps, there is a logical explanation for these effects as well. Let's look at non-locality. It's predicted by the math of QM and has been verified experimentally. So how is this possible? One solution is to look at the Universe in a holistic fashion as a single quantum computer, running the math of QM and determinism and the transition from one to the other. Then, the seeming communication between particles at a distance is really just a math program running on a computer. One bit of code describes one particle, and another bit of code describes the other particle, and QM describes the relationship between the particles. There is then nothing mysterious about non-locality, since all the math is run on the same computer, distance between the particles isn't even a factor in the computation. Thus, the problem of non-locality is efficiently disposed of. No additional physics is required, other than the physical laws governing the transition from probabilistic to deterministic reality, as discussed previously. Of course, all of this is just my own humble opinion.

 

[IllyaKuryakin]

Well, it's a paradox so there is a faulty assumption. I wouldn't try to resolve that by reference to the reality of the wave function. And I don't pretend to be able to explain what collapse is. Is it physical and objective? I dunno, wish I did. All I can say is that the existence of interference effects, as well as the ability to reconstruct a superposition, leads me to conclude that the wave function has objective reality. And I would say that the experimental evidence supports this view.

If QM math does not just model objective reality, but is in fact a part of objective reality itself, basically running on the quantum computer of the Universe, then yes, the waveform is objectively real. Classical determinism is also objectively real, but it's a different set of equations running on the same computer. Decoherence is perhaps a mathematical link between the two, but we just haven't discovered all the math to that process yet. As odd a notion as it seems, I believe it completely agrees with experimental evidence. Of course, I must credit Seth Lloyd and his, "The computational Universe" for that concept.

To put a sharper point on it, our perception of objective reality is only that, a perception. It is not reality itself. Reality is only the math. Of course, for that to be true, the math must be processed somehow, and that's where the concept of the Universe being a quantum computer comes in.

Here's how Dr. Lloyd looks at it: http://www.edge.org/3rd_culture/lloyd2/lloyd2_print.html

 

[Rap]

So, let's accept that both are true, and the transition from QM behavior to deterministic occurs at some small level and we just don't know yet what physical laws govern that transition.

No, there is no transition, its just that the probabilistic aspects of QM become negligible (but not zero!) in the macroscopic realm. Ultimately, to form a complete theory, GR will have to incorporate quantum indeterminism.

In that case, I have to reverse my earlier conclusion and say, I agree, if a tree falls in the woods, and no one observes it, it's just a tree that fell deterministically, and it made a sound whether anyone observed it or not. So, logic holds and all is well with the Universe, Yes? No, not yet.

Science is about repeatable, measurable events. A single tree falling in the woods that no one observes, is unrepeatable and unmeasured, therefore it is not properly a subject for scientific inquiry.

 

[StevieTNZ]

'Quantum Enigma' by Bruce Rosenblum - consciousness collapses the wave function

'Quantum Reality: Theory and Philosophy' by Jonathan Allday - ability to infer or not infer information about which path the particle collapses determines whether interference is observed or not

'The Quantum Challenge' (2nd edition) by George Greenstein & Arthur G. Zajonc - pags 110-113 - mentions of having partial information and the resulting interference.

 

[jibblesmgee]

This is more like Confucius than Copenhagen. You have to keep in mind Schrodinger's Cat was more of a joke at probability than a proof for it. The reason the star doesn't exist to you as an observer if it's 50,000 lightyears away and was just created is that all the information we can observe from it doesn't reach us for at least 50,000 years. So this is the speed that time travels as well. This is a General Relativity idea. I think it's been fairly well proven that the energy density of space dictates the vector of the constant (curvature of spacetime)

Please correct me if I'm wrong (I'm a physics student, so I'm used to being wrong.)

 

[IllyaKuryakin]

No, there is no transition, its just that the probabilistic aspects of QM become negligible (but not zero!) in the macroscopic realm. Ultimately, to form a complete theory, GR will have to incorporate quantum indeterminism.

Experimental results show no probabilistic scattering of in GR test data at all, so I can't see how this can conform to those results. The results indicate that the transition, or decoherence if you like, from QM to GR is complete at larger scales.

 

[IllyaKuryakin]

'Quantum Enigma' by Bruce Rosenblum - consciousness collapses the wave function

'Quantum Reality: Theory and Philosophy' by Jonathan Allday - ability to infer or not infer information about which path the particle collapses determines whether interference is observed or not...

Yes, this has been seen experimentally. It seems as if the particle knows if we are looking at it or not. Obviously that is a mis-perception of reality and any complete hypothesis must account for this experimental data. This may be the proof of the hypothesis that the math is the true reality and that our perception of reality is flawed. If one accepts that the math of QM is the only true objective reality, then there is no conflict or paradox. There is something we don't completely understand, i.e. the physical laws that govern the decoherence, but that is receiving intense study and will be resolved in time.

 

[IllyaKuryakin]

This is more like Confucius than Copenhagen. You have to keep in mind Schrodinger's Cat was more of a joke at probability than a proof for it. The reason the star doesn't exist to you as an observer if it's 50,000 lightyears away and was just created is that all the information we can observe from it doesn't reach us for at least 50,000 years. So this is the speed that time travels as well. This is a General Relativity idea. I think it's been fairly well proven that the energy density of space dictates the vector of the constant (curvature of spacetime)

Please correct me if I'm wrong (I'm a physics student, so I'm used to being wrong.)

We are all students of physics :) Consider that the light of the star may have reached Earth one billion years before it was observed by any living thing. The waveform of the particles that created the light should not have collapsed and each photon should have only been a probability, not a physical reality for that billion years. Obviously, this is a mis-perception of what the math is trying to tell us. Removing the preferred position of the observer removes that mis-perception. Then the waveform collapses through interaction with the environment, or by a process of decoherence if you like, independent of the preferred position of the observer. It's only the lack of understanding of the physical laws that govern the decoherence that foster the mis-perception that the particle knows if we are observing it or not. Of course, this is only a logical hypothesis. Without knowing the physical laws that govern the decoherence, I can't prove it theoretically.

 

[StevieTNZ]

Then the waveform collapses through interaction with the environment, or by a process of decoherence if you like, independent of the preferred position of the observer. It's only the lack of understanding of the physical laws that govern the decoherence that foster the mis-perception that the particle knows if we are observing it or not. Of course, this is only a logical hypothesis. Without knowing the physical laws that govern the decoherence, I can't prove it theoretically.

Again, isn't decoherence just a creation of a more complex superposition, not a mixture? Nearly a mixture doesn't do it.

 

[IllyaKuryakin]

Again, isn't decoherence just a creation of a more complex superposition, not a mixture? Nearly a mixture doesn't do it.

Well, there are people who hold strong opinions about how this could or should work, but I haven't seen adequate proof that anyone quite knows yet. There are some top experimentalists working on it now. Hopefully we'll have some results soon. If someone has better information, perhaps they will share?

 

[MEMoirist]

If the universe itself is a sentient creature, then there is an observer to everything. We are the universe observing itself

 

[yoda jedi]

I think the problem behind this stuff is the lack of a precise definition of "information" (in quantum mechanics) and "reality".

reality (ontology) is simply what exists.
if we know it or as we know it or not, is information (epistemic).




.

 

[IllyaKuryakin]

If the universe itself is a sentient creature, then there is an observer to everything. We are the universe observing itself

Now that's a "way out there" idea. But, honestly, it's not that far away from considering the Universe as a giant quantum computer running the program we call "reality".

The experimental evidence is clear, but not logical. On a quantum scale, until something is observed, it is a probability distribution. It simply does not exist in the definite sense of either being there or not being there. The experimental evidence for this is irrefutable. But on the macro scale, we see no evidence of reality being a probability distribution. The most careful measurements of classical reality, such as GR, show no probability distributions at all on the macro scale. Therefore, there must be a transition from quantum to classical reality at some small scale, call it decoherence or whatever you like, and that transition must be governed by definable physical laws.

Experiments seem to indicate that decoherence is a continuous process rather than a discrete one as one might expect. Something along the lines of quantum states becoming entangled with the classical states of the surrounding environment, essentially drawing the quantum reality into classical reality particle by particle.

Another equally valid way to look at this is the pure quantum states have very low entropy (high information content) and as the decoherence occurs, information is lost to the environment like mixing a few drops of yellow paint into a bucket of blue paint. The problem with this analogy is that even though the bucket of blue paint might seem just as blue to the eye, sophisticated measurements could detect the the slight difference in absorption of different wavelengths of light caused by the addition of just a few drops of yellow to a bucket of blue. Measurements of classical macro objects do not show just a slight probabilistic nature, they show none at all. As someone said, it's either a mixture of states, or it's not. Almost being a mixture isn't an explanation.

But this way of looking at it, with classical reality being of very high entropy and quantum states being of very low entropy and decoherence being the process of information transfer from quantum to classical reality is at least an approach that is subject experiential investigation. Of course, being part of the macro world, any time we observe a quantum object, we must logically be transferring information from the quantum to classical environments, therefore requiring decoherence. This gives the silly impression that a photon knows if we are observing it or not. This thermodynamic interpretation would simply say that that by observing the photon and gathering information about it, or from it, we are forcing decoherence as defined by an information transfer from the quantum states to the classical environment. If that is the case, the special position of the conscious observer can be removed from the process and the Copernican principle remains intact.

Does this answer all our questions? I believe so. If a tree falls in the woods, and no one observes it, does it make a sound? Yes, because the tree and surrounding air are already classical macro objects and behave as such. Does the moon exist if we aren't looking at it? Yes, by the same logic. Does the observation of a distant star by a bug in Copenhagen instantly collapse the waveform of every particle in that star? No, because the bug passes away peacefully in it's sleep one night, never having transferred any information to the environment. But if a human makes the same observation, does the waveform collapse?

If the human acts as a transfer function to transfer information from a quantum reality, say a photon emitted by an excited hydrogen atom, to a classical environment, say a star chart. Then by this definition, yes, at least some decoherence is forced by the information transfer. That decoherence may represent a very tiny percent of the total mass of the star, as someone noted earlier, but the math says some tiny amount of decoherence must occur nonetheless.

I believe this thermodynamic interpretation is the only one that is logically consistent and passes the test of reasonableness. You can look at it as though the human consciousness possesses some special power to crystallize quantum probabilities into classical reality if you like. That math works fine, but the concept leads away from the truth as we know it that we really aren't that special in the Universe. You can look at the many worlds interpretation, and believe that every time a leaf falls from a tree face up or face down, the entire universe splits into two separate and complete universes, one with the leaf up and one with the leaf down. The math works just as well, but the concept is silly.

As far as dedoherence appearing to be a continious process, rather than a discrete one, if the smallest amount of information that can be transferred is smaller than our ability to measure it (I leave definition up to the reader, but a very small bit), the transition may appear to be continious to the best of our measurement ability, when in fact it is a discrete process.

I propose we accept the thermodynamic interpretation of QM as the only interpretation that is logically consistent and subject to scientific investigation, and proceed with that investigation with all due haste. This is of course just my opinion. Others may have reasonable differences, and I'd be happy to hear from them.

 

[IllyaKuryakin]

Well, now we have our answer. It's here:
http://www.physorg.com/news/2011-06-quantum-physics-photons-two-slit-interferometer.html

More info here:

http://en.wikipedia.org/wiki/Louis_de_Broglie

And more here:

http://en.wikipedia.org/wiki/De_Broglie_hypothesis

Thanks to the hard working researchers for answering these questions for us. Now, we don't have to believe that a whole new universe is formed everytime a leaf falls face up or face down, and we don't have to believe the universe wouldn't be here if we were not here to observe it. There is a third alternative that now agrees with experimental evidence. It's all just simple thermodynamics.