Can Reproduction and Darwinism Explain Quantum Mechanics' Observer Effect?

[WaveJumper]

Decoherence doesn't address the issue of what happens to the other states when a single outcome is selected through loss of information to the environment and it is presumed those waves are real(in most formulations). MWI is too much of a baggage with its trillions of universes, i reject it on Occam's razor grounds.

"Leak of information" is a rather weak explanation as to why a certain single eigenstate is preferred. It is in fact no explanation at all for classical reality, but just a mechanism that might be useful in a future theory with greater explanatory powers. The only way decoherence makes sense as it is, is when coupled with MWI where every probability is realized in a different universe. But i am not convinced that believing in ghosts, the Loch Ness monster and blood sucking aliens is not easier to swallow. I can imagine Einstein asking Pais:

"Do you really think a new 72 billion light years across universe is created everytime a dung beetle moves its antennae?"

 

[Freeman Dyson]

Yet, there is at least one glaring omission in present physical theory. This is how small-scale quantum processes can add up, for large and complicated systems, to the almost classical behaviour of macroscopic bodies. Indeed, it is not just an omission but an actual fundamental inconsistency.

-Penrose

Has anybody heard of quantum darwinism?

Did you know there was such a thing as 'Quantum Darwinism'? Indeed there is, and it postulates the theory that quantum mechanical states are selected and reproduced.

The team also succeeded in finding clear indications of Quantum Darwinism, that is to say the notion that during interaction with the environment only the "strongest" states - the pointer states - remain stable and are able to create offspring.

A team of physicists has proved a theorem that explains how our objective, common reality emerges from the subtle and sensitive quantum world.
If, as quantum mechanics says, observing the world tends to change it, how is it that we can agree on anything at all? Why doesn't each person leave a slightly different version of the world for the next person to find?

Because, say the researchers, certain special states of a system are promoted above others by a quantum form of natural selection, which they call quantum darwinism.

http://www.scientificblogging.com/news_releases/can_there_be_quantum_darwinism

 

[apeiron]

Has anybody heard of quantum darwinism?

I thought you were referring to Zurek who coined the term...

Quantum Darwinism is a theory explaining the emergence of the classical world from the quantum world as due to a process of Darwinian natural selection. It is proposed by Wojciech Zurek and a group of collaborators including Ollivier, Poulin, Paz and Blume-Kohout.
http://en.wikipedia.org/wiki/Quantum_Darwinism

Penrose was instead exploring the idea that gravity was responsible for the collapse.

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

One could be called a subjective approach, a collapse of the wavefunction from the outside by the "observation" of a system.

The other is objective in that the collapse happens due to what is going on "inside" the wavefunction itself.

 

[apeiron]

"Leak of information" is a rather weak explanation as to why a certain single eigenstate is preferred. It is in fact no explanation at all for classical reality, but just a mechanism that might be useful in a future theory with greater explanatory powers. The only way decoherence makes sense as it is, is when coupled with MWI where every probability is realized in a different universe.

Wavejumper, you are putting your finger on what I find "too clunky" about decoherence modelling to date. But I don't see MWI as the fix at all.

The way I view it is that the classical universe is a "QM uncertainty dissipating structure" (so I am expecting an even more thermodynamic slant to the eventual interpretation machinery).

The universe is a system of constraints. At this constraint is felt with increasing definite effect as scale grows. So while the constraint or "collapsing observation" is weak near the Planckscale, it would grow with powerlaw vigour with physical scale. Or perhaps exponential. And so in our classical realm, QM uncertainty is decohered on a very fine grain generally, but also potentially can have fractally large scale - escape decoherence for quite a while.

An analogy would be an ideal gas. Take a box with a bunch of gas particles at gaussian equilibrium. Insert a much hotter or colder particle and quite quickly it will be "decohered" to the ambient average state. The idea gas is a system of constraint that can't necessarily get you right away, but will get you on some emergent average scale.

"Do you really think a new 72 billion light years across universe is created everytime a dung beetle moves its antennae?"

That would be crazy. As there is no evidence to suggest it happens.

But just about as crazy is what must be true when you look into the night sky, and see a distant star. QM tells us that there is a dance, a collapse over a sum of histories, between some excited stellar atom and the photoreceptor in your eyeball. To account for known QM effects, this has to be a retrocausal link with a "nonlocal" aspect.

So classical reality is probably best viewed (via systems decoherence, rather than environmental decoherence, perhaps) as a mesh of such interactions, such collapse events. Some of the events have vast scale (point-to-point event across millions of lightyears). But statistically, the great majority of events are quick and local collapses. Two atoms in the star are far more likely to make that photon connection.

Maybe even virtual particle interactions stabilise classical reality before things get that far, creating the true baseline? That seems to be where some theories like Wilczek's condensates are pointing.

Anyway, the natural commonsense expectation of a sound interpretation of QM would seem to revolve around the idea of one generally classical universe which becomes a sort of homogenising, wavefunction dissipating, equilibrium structure. There is no observer as such as observation, or constraint, is present everywhere. The history of where the universe has been becomes the general shape of what can happen next. Then QM uncertainty intrudes on the fine grain to make things a bit unpredictable and creative - in a predictable average sort of way.

Well, my expectation that this is a natural approach is probably due to my familiarity with systems science in biology and neuroscience where this kind of anticipatory or forward-modelling logic is the norm.

 

[Moonbear]

Bolting on the theory of evolution and how it seems nature has a tendency towards complexity we can take this idea one step further.

I haven't read anything else in the thread, but you have a seriously flawed premise here. Nature has no such tendency toward complexity, and that would have nothing to do with evolution. Evolution can and does happen in any direction.

 

[apeiron]

I haven't read anything else in the thread, but you have a seriously flawed premise here. Nature has no such tendency toward complexity, and that would have nothing to do with evolution. Evolution can and does happen in any direction.

Of course there is a trend to complexity in nature. This is what dissipative structure theory, maximum entropy production principle, entropy degrader approaches, and other stuff is all about.

Order exists because it accelerates disorder. That is what life and mind are all about.

What you perhaps mean is that evolution itself - the darwinian selection mechanism - is essentially uncreative and homeostatic. And modern theoretical biology would agree. That is why they split biological systems into evo and devo.

Development is about the self-organisation into complex dissipative structures. Then evolution is about the constraints exerted by an environment that limit the possibilities.

So a tree could sprout limbs and leaves in many branching patterns. But all sorts of accidents of circumstance in an actual forest limits it to some actual pattern of branching.

The tree - viewed as devo - wants to be as complex as possible in its branching to dissipate as much as it can. Then evo forces may knock off branches, chew its leaves, shade it out, starve its roots - act in blind and undirected fashion.

 

[Coldcall]

Do you have some references regarding this failure? My impression is that it has become the mainstream approach over the past decade.

While I would agree that the detailed machinery offered by Zurek and others is too clunky to be satisfactory, the general idea of the Universe as a system that is decohering events over random spatiotemporal scale seems the right one. It puts the "observer" everywhere and nowhere in the system.

Apeiron,

The evidence regarding the failure of "decoherence" to address the measurement problem is in the public domain. Even Zurek, one of the founders of "decoherence" admits its not a solution to the measurement problem.

And if you think it does solve the MP then you have been misled in a big way.

 

[Coldcall]

I haven't read anything else in the thread, but you have a seriously flawed premise here. Nature has no such tendency toward complexity, and that would have nothing to do with evolution. Evolution can and does happen in any direction.

Apeiron has answered your post well. In fact i find it laughable you actually made this post because clearly you have never read any studies on natural complexity, natural self-organisation and the wider areas of chaos theory.

I suggest you go to the library.

 

[WaveJumper]

Apeiron,

The evidence regarding the failure of "decoherence" to address the measurement problem is in the public domain. Even Zurek, one of the founders of "decoherence" admits its not a solution to the measurement problem.

And if you think it does solve the MP then you have been misled in a big way.

Yes, there doesn't appear to be a way to resolve the measurement problem without admitting that our conscious activities(also referred to as measurements/observations) 'collapse' wavefunctions to 'particles'. Most of the interpretational problems of QM start and end at the double slit.

Quantum entanglement and Bell's conclusion that if QM is right, reality cannot be both local and realistic is very anti-realistic. "Local realistic" is the perception of the average Joe on the street as to how the world is. This view, however, isn't supported by experiements. I've yet to see a sensible explanation of what a non-local but realistic world is supposed to be; this cannot be a feature of a purely materialistic world.

 

[apeiron]

The evidence regarding the failure of "decoherence" to address the measurement problem is in the public domain. Even Zurek, one of the founders of "decoherence" admits its not a solution to the measurement problem.
And if you think it does solve the MP then you have been misled in a big way.

My own feeling was that Zurek's early papers (along with what others like Gell Mann were saying) was creating the right framework, but then along the line the thinking became contorted trying to cash out new formal machinery.

For me, the big problem is always in anchoring observation back to a static, located, human observer when reality is dynamic and self-organising (I presume from a systems science standpoint). So observers and their measurements have to be generalised in that direction, taking the nod from global boundary constraints thinking.

So in this view, decoherence would be about expanding light cones of QM potential. When spatiotemporal scale is still small, the potential has little context and so is less likely to encounter some crisp collapsing context. But as scale grows, it become rapidly more likely that collapse will occur.

This is hard to explain unless you can think about QM potential as a vagueness. There is not even a wavefunction crisply existent until the scale, the field of view, has grown enough to take in, say, a pair of particles who could frame some definite exchange.

It is a phase transition view I guess. When scale is small, you may have in effect a particle surrounded by a vague QM potential to "do something". The particle's gravity, EM, give it a QM potential or "presence" that propagates as a spherical boundary moving at speed of light. But it is a very raw QM state - like a chaotic jostle of dipoles in a hot bar magnet.

Then the scale grows large enough so that a second particle comes within exchange range. At that point, a crisp wavefunction can exist. There is a global boundary condition that can create constraint of that vaguer potential. General limits to what can happen are created and then something does happen. It is like the sufficient cooling that allows a crisply divided local~global state of order in a magnet.

In effect, the wavefunction and its collapse are two faces of the same thing. The wavefunction was not "always there and evolving" in an independent sense. Instead there was a rawer potential for somethingness developing, then a crisp QM wavefunction/crisp classical collapse did something with that spreading potential. We only impute an evolving wavefunction after the fact.

OK, I'm thinking aloud here as this was the general picture I took from Zurek's early writings about decoherence, combined with what I was hearing at the time from quantum vagueness guys like Chibeni (that stuff seems to have died a death sadly), and Cramer's convincing arguments for retrocausality. Plus, as I say, what seems obvious from a phase transition, systems science, way of looking at reality.

Zurek seems to be working in the right area on this...
http://arxiv.org/PS_cache/cond-mat/pdf/0701/0701768v2.pdf

But I think the key thing missing is the idea that QM information starts vague and needs a classical context to turn it into crisp QM probabilities, even if the crisp QM probabilities are still of the crisply entangled, uncertain and superimposed probabilities on the wavefunction side of things.

Boiling it down, the usual framing of the measurement problem is that we have an evolving wavefunction forever in search of the machinery that forces its collapse. The difficulty in seeing why the wavefunction should collapse (because no internal mechanism or hidden variables are permitted) leads people to say collapse requires consciousness, or perhaps in many worlds fashion, never happens.

Decoherence is broadly the attempt to put the collapse machinery back out there in the physical world. And really it would be good to have it happening as a global boundary constraint - that is, something that is presence and active over all classical spatiotemporal scales. (technical note: global means thermodynamic macrostate rather than "largest size").

Then what I take this to require is that the collapse machinery in fact manufactures the wavefunctions out of rawer QM potential. So it is the collapse that causes the wavefunctions, not the wavefunctions and that must produce a collapse.

 

[Freeman Dyson]

I will throw another thing out there that I have been interested in over the years:

Synchronicity

That events are tied together by purpose. By meaning. That is the connecting principle. Only meaningful and purposeful things happen. Classical objects form from quantum states because they are meaningful/purposeful objects.

Kind of out there I know..

 

[disregardthat]

Yes, there doesn't appear to be a way to resolve the measurement problem without admitting that our conscious activities(also referred to as measurements/observations) 'collapse' wavefunctions to 'particles'. Most of the interpretational problems of QM start and end at the double slit.

Quantum entanglement and Bell's conclusion that if QM is right, reality cannot be both local and realistic is very anti-realistic. "Local realistic" is the perception of the average Joe on the street as to how the world is. This view, however, isn't supported by experiements. I've yet to see a sensible explanation of what a non-local but realistic world is supposed to be; this cannot be a feature of a purely materialistic world.

Science does to a certain degree assume a realistic perspective, but my opinion is that this is only because of the context in which scientific predicates usually are understood. An important insight is that scientific predicates only says something about our perception, and the scientific body of knowledge represents the structure of perception. Realism posits that the world is mind-independent, and that scientific predicates makes sense in the absence of a mind understanding it and giving it meaning. But this is a senseless view in my opinion. The world independent of the mind can not be said anything about. It makes no sense to make a distinction between objects in a mind-independent world, it makes much less sense to talk about properties of objects, not even spatial and temporal properties. These are all conceptual characteristics. We see these characteristics of objects because through perception our minds interpret sensations with spatial and temporal structure. I find the anti-realistic view much more appealing. It also rid itself of many problems the realist view stumble into.

The results of QM are very interesting, and we couldn't find a better tool to propagate these points through with. My knowledge of QM is however limited, but it is my understanding that objects under observation more or less behaves as we would expect. Perhaps you, apeiron, are more knowledgeable about Kant's metaphysical theories about the necessities for experience than me and hopefully you have a comment on this. I find it incredibly interesting how Kant's points are manifested through the results in quantum mechanics.

 

[apeiron]

I will throw another thing out there that I have been interested in over the years:

Synchronicity
.

Experiment has already put tight parameters around such connectedness. So while QM supports nonlocal (making the global context meaningful and not just an a-causal void) it also limits the nature of the connection in very strict fashion.

You could argue that the psi research literature does the same from a different angle. If any kind of spooky stuff exists in a mind-entangling complex way, the signal is so small as to be swamped by experimental artifact and experimenter fraud.

So yes. Any theory can be entertained. But synchronicity in any Jungian sense has a stack of negative findings against it now.

 

[apeiron]

Science does to a certain degree assume a realistic perspective,

The realist vs anti-realist choice, as you put it, does offer also a third path other than a binary either/or.

You can instead say we need to model in terms that include both - both modeller and modeled, observer and observed.

Which is the essence of what Pattee, Rosen, Salthe and others in the semiotic, systems science, camp would be doing.

 

[disregardthat]

The realist vs anti-realist choice, as you put it, does offer also a third path other than a binary either/or.

You can instead say we need to model in terms that include both - both modeller and modeled, observer and observed.

Which is the essence of what Pattee, Rosen, Salthe and others in the semiotic, systems science, camp would be doing.

I don't think that the anti-realist is rejecting realism on behalf of his own perspective, that would be violating the very "ideology". The realistic perspective is a perfectly "valid" perspective in the anti-realistic sense as it is a coherent system of beliefs as any. But I agree with you if I understand you correctly. But instead of talking about a "third way", we can remove the clear-cut distinction between realism and anti-realism. In a way, anti-realism incorporates both perspectives. The reason I find anti-realism appealing is the rejection of subscribing to any specific set of beliefs or any specific ideology.

 

[apeiron]

I don't think that the anti-realist is rejecting realism on behalf of his own perspective, that would be violating the very "ideology".

We would agree then that "all is modelling". We start from a position of subjectivity and have to operate on that basis. The question then becomes how to we move towards the impossible ideal of an "objective" understanding.

The third way I'm talking about is very much concerned with just how to do this properly. And a central issue is how to make the epistemic cut, how to make a separation between observer and observed, given that we are stuck in a position of subjectivity.

Mainstream physics does just jump to realism. Or rather, being based on a positive, pragmatist, epistemology, it agrees all is modelling, and just models the observables. The observer is placed outside the description.

Well, with GR, the observer became part of the model to an important extent. With QM, the role of observers was made both crucial and obscure.

I guess a lot of people imagine that a ToE would do away with the need for observers perhaps. Their partial inclusion in physical models is an embarrassment and the urge is to find deeper theories that are just about naked observables. Meaningless information.

So the alternative would be to instead get observers and meaning-making into a ToE.

 

[disregardthat]

We would agree then that "all is modelling". We start from a position of subjectivity and have to operate on that basis. The question then becomes how to we move towards the impossible ideal of an "objective" understanding.

The third way I'm talking about is very much concerned with just how to do this properly. And a central issue is how to make the epistemic cut, how to make a separation between observer and observed, given that we are stuck in a position of subjectivity.

Mainstream physics does just jump to realism. Or rather, being based on a positive, pragmatist, epistemology, it agrees all is modelling, and just models the observables. The observer is placed outside the description.

Well, with GR, the observer became part of the model to an important extent. With QM, the role of observers was made both crucial and obscure.

I guess a lot of people imagine that a ToE would do away with the need for observers perhaps. Their partial inclusion in physical models is an embarrassment and the urge is to find deeper theories that are just about naked observables. Meaningless information.

So the alternative would be to instead get observers and meaning-making into a ToE.

I agree with you on this. The realism of science is useful if the context in which it is being used is understood anti-realistically. I think Kant has a unique and interesting approach to this question however. By investigating what dimensions are necessary for experience he could logically deduce what framework/context our experience necessarily must be within. It seems that quantum mechanics implicitly shows us that this road should be taken.

The search for "the theory of everything" in a realistic sense is chasing ghosts IMO. Whatever knowledge we might have is a plateau on which we can construct new buildings of knowledge. The depth of our knowledge is not reaching a singularity, rather, its breadth is growing exponentially.

Quantum mechanics again shows us the need for the observer as more or less an integral part of any theory.

Also, it seems that the breadth of knowledge is not bounded by any objective restrictions, but that our own expectations are creating the holes which in turn needs explanations. This is however only speculation of the nature of knowledge.

 

[tj8888]

Interesting discussion. I just finished reading Lanza's Biocentrism. All the good stuff seems to be what Wheeler already thought up with the Participatory Anthropic Principle. Although I have to admit I never quite understood how Wheeler could violently resist the idea that consciousness was involved in wave function "collapse" but yet insisted observers were essential. I take it this is not an uncommon position so maybe someone can enlighten me there.

Something I have been pondering is what the implications of a PAP like theory would be for SETI. It seems to me it would suggest we are likely to be alone in the universe (and so would provide a possible solution to the Fermi paradox). If we are responsible for the fine tuning then it seems less likely that other formulations of life could exist, especially if one aspect of this fine tuning involves our relative temporal location with respect to cosmic expansion, galactic formation, etc.

 

[Coldcall]

Interesting discussion. I just finished reading Lanza's Biocentrism. All the good stuff seems to be what Wheeler already thought up with the Participatory Anthropic Principle. Although I have to admit I never quite understood how Wheeler could violently resist the idea that consciousness was involved in wave function "collapse" but yet insisted observers were essential. I take it this is not an uncommon position so maybe someone can enlighten me there.

Something I have been pondering is what the implications of a PAP like theory would be for SETI. It seems to me it would suggest we are likely to be alone in the universe (and so would provide a possible solution to the Fermi paradox). If we are responsible for the fine tuning then it seems less likely that other formulations of life could exist, especially if one aspect of this fine tuning involves our relative temporal location with respect to cosmic expansion, galactic formation, etc.

Lanza's Biocentrism is a poor-mans, dumbed-down version of PAP. In my view its sort of a scandal that Lanza claims this is his theory.

Yes you bring up a really interesting point in regards to the potential of other life in the universe. Even Brandon Carter who first coined the "anthropic prinicple" apparently now regrets using the term "anthro" because it implies human life is solely reponsible for the defintion of the universe and its properties, which was not intended.

I also agree with you that Wheeler ended up confusing his original theory by stating that "consciousness" was not vital for wave function collapse. I think he was doing two things by saying this

a) He perhaps thinks that the first lifeforms did not have "consciousness"
b) He did not want to appear to be endorsing "consciousness causes collapse", as this idea is still too anti-copernican for the scinetific community which has real problems quantifying and defining "consciousness".

But going back to your point, I'm not sure that PAP would mean we are somehow alone in the universe. If a universe which can evolve lifeforms is self-selected from an infinite number of virtual universes, as is the main thrust of PAP, then life would be possible all over the universe not just locally in our neighborhood. Once our universe collapses into a reality, life on Earth and anywhere else with suitable conditions is almost a forgone conclusion. Does it matter whether the first lifeform capable of interacting or sensing reality originated locally or in some galaxy on the other side of the universe? I don't think so.

I am of the opinion that once life is possible somehwere its possible anywhere within that same universe which has the life-bearing conditions.

 

[tj8888]

But going back to your point, I'm not sure that PAP would mean we are somehow alone in the universe. If a universe which can evolve lifeforms is self-selected from an infinite number of virtual universes, as is the main thrust of PAP, then life would be possible all over the universe not just locally in our neighborhood. Once our universe collapses into a reality, life on Earth and anywhere else with suitable conditions is almost a forgone conclusion. Does it matter whether the first lifeform capable of interacting or sensing reality originated locally or in some galaxy on the other side of the universe? I don't think so.

I am of the opinion that once life is possible somehwere its possible anywhere within that same universe which has the life-bearing conditions.

I have been thinking about this some more and I think it also depends on how PAP would work and how you define universe. I was under the impression that Wheeler thought the fine tuning wasn't a sudden collapse of the entire universe's wave function but more of a gradual process that fine tuned things as different areas of the "virtual universe" interacted with observers.

The more I think about PAP the more I realize how vague the idea is (or maybe I just don't understand it well enough). It seems like there is a range of starting points. You could say that initially there was nothing at all and somehow everything came into being in a PAP sort of system. I think the more common kind of suggestion is there were quantum laws at first but other things were fine tuned by observation. Who knows if spacetime dimensions would be a priori or created by observation either. So for PAP I think a lot depends on what the initial restrictions are.

If different life forms could arise in a virtual universe at roughly the same time and fine tune different areas differently we could maybe see their galaxy and the altered laws and constants, etc. Obviously that hasn't happened, so maybe it would just be really improbable. Maybe their fine tuning would have to be consistent with any other tuning no matter how far away. Or maybe the differences in physical laws would be so fundamental our area of the universe couldn't even interact with theirs, so in that sense they wouldn't even be in the same universe as us.

Trying to make sense of the theory makes me think PAP is completely insane and yet I can't help thinking it is where most of the evidence points to.

 

[apeiron]

Trying to make sense of the theory makes me think PAP is completely insane and yet I can't help thinking it is where most of the evidence points to.

For me, the idea of conscious humans being somehow special enough to collapse the universe's wavefunction was so plainly nuts I've never investigated the detail.

But just for the fun of the argument, how would PAP deal with the rest of the universe that presumably lies over the event horizon. Our collapse of the wavefunction should be limited to our lightcone, shouldn't it?

So this consideration would seem to force the corollary that consciousness is evolving everywhere at much the same time (which is plausible), or that much of the universe remains in superposition because we are not yet aware of its existence.

 

[WaveJumper]

For me, the idea of conscious humans being somehow special enough to collapse the universe's wavefunction was so plainly nuts I've never investigated the detail.

But just for the fun of the argument, how would PAP deal with the rest of the universe that presumably lies over the event horizon. Our collapse of the wavefunction should be limited to our lightcone, shouldn't it?

So this consideration would seem to force the corollary that consciousness is evolving everywhere at much the same time (which is plausible), or that much of the universe remains in superposition because we are not yet aware of its existence.

The apparent 'collapse' is instantaneous across the universe, which is one of the reasons for the tension between quantum theory and GR. There is no event horizons for non-local effects.
A good case can be made that matter, time and space as we see them manifested in the macro realm, exist only in the classical domain. This has led many a scientist to conclude that such effects cannot be physical and that at its deepest level reality is one(or that the universe is a hologram, projection, a manifestation of a special, emergent case that will be explained, mathematical universe, consciousness causing collapse, relational universe, etc.). This is assuming that human logic is capable of describing reality at all its levels.

BTW, the metric expansion of space is a pretty solid argument that the 'outside' dimensions of the universe are zero or very close to zero.

Most of the questions in the philosophy forum tend to concern the foundations of physics, its building blocks, the assumptions that we've taken for granted for millenia and some consider them now facts. However, let me quote Smolin from 'The trouble with physics'(introduction) - "Those scientists who work on the foundations of any given field are fully aware that the building blocks are never as solid as their colleagues tend to believe".

 

[apeiron]

The apparent 'collapse' is instantaneous across the universe, which is one of the reasons for the tension between quantum theory and GR. There is no event horizons for non-local effects.

Are you sure about that? It would be great if you had references that discuss the issue.

My understanding was that to be entangled, two particles would have to be created at a location. Then they could only separate at the speed of light max. And so even if collapse is "instant", it reaches only across that lightcone. Regions of the big bang not in light range at the start of our particular lightcone would not be part of any later collapsing within our lightcone.

The closest I can find to a discussion on this point concerns entangled particles crossing the event horizon of a black hole. The answer as to what happens seems to be contentious still.

Signaling, Entanglement, and Quantum Evolution Beyond Cauchy Horizons (http://www.arxiv.org/abs/gr-qc/0409112)

https://www.physicsforums.com/archive/index.php/t-43418.html

 

[WaveJumper]

Are you sure about that? It would be great if you had references that discuss the issue.

My understanding was that to be entangled, two particles would have to be created at a location. Then they could only separate at the speed of light max. And so even if collapse is "instant", it reaches only across that lightcone. Regions of the big bang not in light range at the start of our particular lightcone would not be part of any later collapsing within our lightcone.

The closest I can find to a discussion on this point concerns entangled particles crossing the event horizon of a black hole. The answer as to what happens seems to be contentious still.

Signaling, Entanglement, and Quantum Evolution Beyond Cauchy Horizons (http://www.arxiv.org/abs/gr-qc/0409112)

https://www.physicsforums.com/archive/index.php/t-43418.html

Yes, I am sure, but there seems to be some misunderstanding. Non-local effects are not constrained to entanglement. Any influence, signalling or effect that is instantaneous(faster than light) and in violation of relativity is non-local.

A consequence of the HUP is that a particle's position and momentum cannot be ascertained and there is always the small but not zero probability that the particle might appear on the Moon, Jupiter or on Andromeda. Anyway, the apparent 'collapse' happens instantaneously across the universe(otherwise we might have been able to see superpositions - at least in the realistic interpretations). You could say that everything is a wave and there is no 'collapse'(MWI), thus making our universe even more abstract. Measure the position many times and you'll see that it will form a wave quanta(field). This is how a statistical picture of matter is built up. Now, with that in mind, the open question is what constitutes the universe if the 'collapsed' quanta we see everywhere were spread throughout the universe with different amplitudes before the seeming 'collapse'?
But this isn't very different in relativity - no object in the universe has fixed, objective properties - mass, speed, energy, length, time... The only concepts that i would count invariant are the 3 dimensions(until i am proven wrong, of course). So if someone claims to know what the universe and reality are and why we see the universe we do, he must have come from the future via a time machine. Heisenberg has nice quote on this:

"We have to remember that what we observe is not nature in itself but nature exposed to our method of questioning."

Change the mode and depth of the questioning and the universe that we thought we knew at the end of the 19th century, gets blurred and we reel into a haze of interpretational issues and debates.

 

[WaveJumper]

Let me sum up what i think is crucial to the debate what the underlying reality might be. There is no object in the universe that can be specified and objectified(having the specific observable values that we see and measure - mass, location, speed, length, momentum, time) without providing a reference frame and a measurement apparatus. Our perceived reality is dependent on these 2 requirements being met and the realism found in our perception is to be found only there, within the constraints of those conditions.
The Big Bang model is an example of a naive, egocentrical explanation of the universe. My expectation is that when the theory of quantum gravity comes along with a new, better understanding of space and time, the Big Bang theory will be quickly pulled off from high school textbooks.

 

[Freeman Dyson]

I like that Heisenberg quote WaveJumper. It reminds me of this Jung one:

"This grasping of the whole is obviously the aim of science as well, but it is a goal that necessarily lies very far off because science, whenever possible, proceeds experimentally and in all cases statistically. Experiment, however, consists in asking a definite question which excludes as far as possible anything disturbing and irrelevant. It makes conditions, imposes them on Nature, and in this way forces her to give an answer to a question devised by man. She is prevented from answering out of the fullness of her possibilities since these possibilities are restricted as far as practible. For this purpose there is created in the laboratory a situation which is artificially restricted to the question which compels Nature to give an unequivocal answer. The workings of Nature in her unrestricted wholeness are completely excluded. If we want to know what these workings are, we need a method of inquiry which imposes the fewest possible conditions, or if possible no conditions at all, and then leave Nature to answer out of her fullness."

 

[apeiron]

Yes, I am sure, but there seems to be some misunderstanding. Non-local effects are not constrained to entanglement. Any influence, signalling or effect that is instantaneous(faster than light) and in violation of relativity is non-local.
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Well let's consider this. You would agree that entanglement would be a within lightcone "instant" collapse and not a supra-lightcone phenomenon? So it is not evidence that collapse could happen between us and everywhere that exists.

It is tricky because the proposition of PAP is that the whole of the universe is in superposition until we turn up to collapse it. Yet we also have some cosmic models that say much of the universe has never been in thermal contact (and so we need some mechanism like inflation to make it so flat). How do we as THE observers then collapse what is beyond our light cone?

A consequence of the HUP is that a particle's position and momentum cannot be ascertained and there is always the small but not zero probability that the particle might appear on the Moon, Jupiter or on Andromeda.
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Ah, but is there a non-zero chance of it appearing beyond the current lightcone of our visible universe?

This would seem to be a new form of black hole radiation if particles can cross event horizons by tunnelling.

[edit] There is of course also the Feynman sum over histories view taken by some, which allows light to travel at all speeds in effect, so even supraluminal. But then it gets summed to lightspeed as other contributions cancel out. However, is this really QM collapse? or QM nonlocal? Is it more than a computational technique?

Anyway, the apparent 'collapse' happens instantaneously across the universe(otherwise we might have been able to see superpositions - at least in the realistic interpretations). .

Which is why I am interested in how realistic it is as an idea given that collapse would seem to me to me restricted to the insides of lightcones.

So for instance, the first PAP collapse happened say 150kya when the first homo sapiens became "conscious enough" LOL. Then since that time, we have collapsed a little bit more as our visible universe has grown in size.

Like MWI, these interpretations seem to be thrown out with rather little real effort to work through all the consequences of what is being claimed.

Quite possibly I am raising an easily dismissed objection. But I read a lot of things and even though, as I admit, I probably usually hold my nose and pass on when PAP crops up, I've not seen these kinds of details tackled.

 

[WaveJumper]

Well let's consider this. You would agree that entanglement would be a within lightcone "instant" collapse and not a supra-lightcone phenomenon? So it is not evidence that collapse could happen between us and everywhere that exists.

It is tricky because the proposition of PAP is that the whole of the universe is in superposition until we turn up to collapse it. Yet we also have some cosmic models that say much of the universe has never been in thermal contact (and so we need some mechanism like inflation to make it so flat). How do we as THE observers then collapse what is beyond our light cone?



Ah, but is there a non-zero chance of it appearing beyond the current lightcone of our visible universe?

This would seem to be a new form of black hole radiation if particles can cross event horizons by tunnelling.

[edit] There is of course also the Feynman sum over histories view taken by some, which allows light to travel at all speeds in effect, so even supraluminal. But then it gets summed to lightspeed as other contributions cancel out. However, is this really QM collapse? or QM nonlocal? Is it more than a computational technique?




Which is why I am interested in how realistic it is as an idea given that collapse would seem to me to me restricted to the insides of lightcones.

So for instance, the first PAP collapse happened say 150kya when the first homo sapiens became "conscious enough" LOL. Then since that time, we have collapsed a little bit more as our visible universe has grown in size.

Like MWI, these interpretations seem to be thrown out with rather little real effort to work through all the consequences of what is being claimed.

Quite possibly I am raising an easily dismissed objection. But I read a lot of things and even though, as I admit, I probably usually hold my nose and pass on when PAP crops up, I've not seen these kinds of details tackled.

These 'details' are not trivial. All this of lightcones talk concerns GR and the macro-scale(or rather the appearance/perception of it). The 'speed' of entanglement has been tested to be at least 10 000 the speed of light(limited by our ability to test beyond those speeds/times - the lowest bound of resolution was 300 trillionths of a second that produced the '10 000' number):

http://www.telegraph.co.uk/science/science-news/3349494/Einsteins-spooky-action-acts-at-10000-times-the-speed-of-light.html

I am not certain that consciousness causes collapse, nobody knows this. Nobody knows what causes 'collapse'(or what consciousness is), all the interpretations seem sloppy and it takes some religious belief before you can jump on their bandwagon. But we do know that the apparent 'collapse' is instantaneous in as much as we can test. Even if the lower bound was true(unrealistic assumption), i.e. the influence between entangled particles traveled at 10 000 times the speed of light, that would be at least 3 000 000 000 km/s^2.
My perspective is that we as observers, are an essential part of how reality is defined and manifested. All these relative concepts of space, time, lentgh, mass that have no definite, fixed values and which are manifested by 'particles' that have no definite observable values before a measurement is carried out suggest that we are living in a relational universe and what we perceive as matter and space is tied to what we are using as a measurement apparatus and the FOR it is in.

So for instance, the first PAP collapse happened say 150kya when the first homo sapiens became "conscious enough" LOL. Then since that time, we have collapsed a little bit more as our visible universe has grown in size.

Time as a concept is problematic, it is often required to assume that time runs backward and forward to explain certain quantum phenomena. In GR, the perceived flow of time is even more problematic. I see you insist on sticking up for Realism, but i see no way out, without changing most of physics as we know it.

 

[apeiron]

These 'details' are not trivial. All this of lightcones talk concerns GR and the macro-scale(or rather the appearance/perception of it). The 'speed' of entanglement has been tested to be at least 10 000 the speed of light(limited by our ability to test beyond those speeds/times - the lowest bound of resolution was 300 trillionths of a second that produced the '10 000' number).

I accept nonlocality to be "instant". And even retrocausal in Cramer sense. But my point was that entanglement and tunnelling cannot (in my understanding) be said to transverse infinite spacetime, only the spacetime within lightcones.

So the collapse can be instantaneous, yet not infinite. And GR defines the scale of "an instant".

If GR did not apply as the upper boundary to QM nonlocality, then we would surely observe supraluminal entanglement, supraluminal tunnelling.

Two tachyons, for example, might be created as an entangled pair. Or might be subject to HUP uncertainty (to the point that they were slower than light and we could observe them perhaps!). Particles could radiate from the inside of black holes (and not just be liberated as stray virtual particles, the Hawking radiation, at the event horizon).

So what you are asserting seems to go counter to many things I thought were accepted.

I don't believe in PAP, and this issue of the extent of any collapse would seem a real problem for PAP enthusiasts.

I do believe in decoherence as a collapse mechanism. And in my view, event horizons are the "observation" that are the decohering environmental context. So if nonlocality is demonstrable beyond lightcones, then I would have to reconsider that.

 

[WaveJumper]

I accept nonlocality to be "instant". And even retrocausal in Cramer sense. But my point was that entanglement and tunnelling cannot (in my understanding) be said to transverse infinite spacetime, only the spacetime within lightcones.

So the collapse can be instantaneous, yet not infinite. And GR defines the scale of "an instant".

I don't think i understand your point. If the Time it takes the influence to reach Andromeda is zero(instantaneous influencing), then the Speed is infinite.

If GR did not apply as the upper boundary to QM nonlocality, then we would surely observe supraluminal entanglement, supraluminal tunnelling.

Entanglement and nonlocality is always superluminal, tests confirm that. You could claim that GR is not violated because no information can be sent over such a 'link' because entangled particles, according to QM, remain in an indeterminite state until measured. But even 10 000 times the speed of light is 'very' superluminal. You seem to adopt Einstein's stance as in the EPR towards "spooky action at a distance", but he was proven wrong more than 40 years ago. Non-locality cannot be explained by any local theory(this is the same as saying "GR light cones are not observed").

Two tachyons, for example, might be created as an entangled pair. Or might be subject to HUP uncertainty (to the point that they were slower than light and we could observe them perhaps!). Particles could radiate from the inside of black holes (and not just be liberated as stray virtual particles, the Hawking radiation, at the event horizon).

I did not claim particles moved at speeds beyond the speed of light, and were able to escape black holes' gravity pull. I merely stated that the causal influence between entangled particles, was traversing instantaneously which renders the speed of propagation infinite.

I don't believe in PAP, and this issue of the extent of any collapse would seem a real problem for PAP enthusiasts.

How would you build a context-independent reality in GR? Where are the objects that have fixed, immutable properties in this universe? Is there even one example? Or in QM?

I do believe in decoherence as a collapse mechanism. And in my view, event horizons are the "observation" that are the decohering environmental context. So if nonlocality is demonstrable beyond lightcones, then I would have to reconsider that.

Non-locality is not about particles prapagating through space, but their causal influence at certain polarization settings. It has been first demonstrated by Alan Aspect in 1982 and several times afterwards.
If you want to stick to realism and decoherence(and not the naive realism of your senses, but to a mind-independent reality), your only option is MWI(and you need to explain what kind of realism can be found in MWI). Instantaneous loss of coherence among states across the universe is not a phenomenon that supports realism.

 

[apeiron]

I don't think i understand your point. If the Time it takes the influence to reach Andromeda is zero(instantaneous influencing), then the Speed is infinite.

OK I can see that you are not getting what I was meaning. But I'm not sure how to explain it more clearly.

Nonlocality is instant. It takes no time. The speed of the collapse is infinite - way super luminal. All the distance is covered instantly.

But... nonlocality (and so the collapse of a wavefunction) is only known to happen across the spacetime of a lightcone. It may take no time to cross all that space, in effect. But it cannot act from outside that lightcone.

Start again, Take two entangled particles. Even if they move apart as fast as possible, by definition they cannot move apart faster than light and so remain forever in each other's light cone. Correct me if I am wrong here of course.

So even if the state of one particle is observed, collapsing the state of the other, it is an instant in time result...but only across a finite space, not infinite space.

Now take two tachyons. Here we can imagine having two particles that are created entangled and then move so fast that they are not within the same shared lightcone. Any collapse would be both instant and across a much greater space than defined by a lightcone.

Now nonlocality may indeed be unrestricted in this fashion. It does not respect the limitations of lightcones and event horizons. But I have not seen this said. If you have references that would be great. However I don't think you were responding to the actual point I had in mind.

Again, an instant connection across a finite space is not the same as an instant connection across infinite space. One is a (lightcone) subset of the other.

 

[WaveJumper]

OK I can see that you are not getting what I was meaning. But I'm not sure how to explain it more clearly.

Nonlocality is instant. It takes no time. The speed of the collapse is infinite - way super luminal. All the distance is covered instantly.

But... nonlocality (and so the collapse of a wavefunction) is only known to happen across the spacetime of a lightcone. It may take no time to cross all that space, in effect. But it cannot act from outside that lightcone.

Yes, because there is no way we and our measuring equipment can ever get out of our light cone. But i see no reason to believe a light cone can be a limit to the instantaneous influence between entangled particles.

Start again, Take two entangled particles. Even if they move apart as fast as possible, by definition they cannot move apart faster than light and so remain forever in each other's light cone. Correct me if I am wrong here of course.

So even if the state of one particle is observed, collapsing the state of the other, it is an instant in time result...but only across a finite space, not infinite space.

OK. We are talking of the visible universe.

Now take two tachyons. Here we can imagine having two particles that are created entangled and then move so fast that they are not within the same shared lightcone. Any collapse would be both instant and across a much greater space than defined by a lightcone.

Now nonlocality may indeed be unrestricted in this fashion. It does not respect the limitations of lightcones and event horizons. But I have not seen this said. If you have references that would be great. However I don't think you were responding to the actual point I had in mind.

Again, an instant connection across a finite space is not the same as an instant connection across infinite space. One is a (lightcone) subset of the other.

I see no reason to believe nonlocality would not hold beyond our future/past light cone.

 

[Fra]

I have an evolutionary, subjective view of this so I might throw in an opinon here.

This theory is based on accepting an observer-centric interpretation of qm. Many won't agree with that but its important in order to make sense of my argument. So let's pretend that the existence of an information processing observer is absolutely vital for physical reality to occur as we experience it in this universe.

Observer-centric is sound with me as long as we don't think observer = human. I have no problems to say picture an atom as an information processing observer.

So if observers are vital for the universe to exist, then the only way the universe becomes sustainable from the perspective of an unfolding reality, is if those observers/biology go on to reproduce new observers which "hold open" the physical reality.
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I know there are problems with this idea because one can argue that the universe appears to have existed a few billion years before any biology evolved,
...
Any comments or arguments most welcome.

But this objection is only an issue if you think observer=human or biology.

If we by observers means any physical system (ie. one atom can "observe" another atom), then I see no reason to give biological evolution special treatment. It should be one the same footing as the evolution of the speices of particle physics.

I think you say that "evolution" started long before the biological evolution then I fully agree. This is also the idea behind ideas where physical law evolves.

What was the first "particle species" occur in this past we call big bang. What was the first interactions that distinguished themselves from a total chaos? Why are the laws of physics like they are? What physical laws could have been distiniguishable to thoese first particle species? perhaps the options was quite constrained - *this is a handle for possible constructive implications of this idea*

The ideas is that in the observer-centric view - even the laws of physics are observer dependent, and the evolution of observes thus goes hand in hand with the evolution of law.

Unfortunately there are as far as I know no worked out mature predictive theories in line with this. Smoling has his Cosmological natural selection which tries to make a prediction about the mass of neutron stars. But I think of that as an inital idea only while the real thing is yet unraveled.

/Fredrik

 

[Fra]

A clarification, since I have a feeling that the common confusion to think of observers and humans also cause confusion as to what subjective law means (in any sensible way that is)

The ideas is that in the observer-centric view - even the laws of physics are observer dependent, and the evolution of observes thus goes hand in hand with the evolution of law.

Observer dependent obviously doesn't mean that scientist 1 and scientist 2 can make consistent and disagreeing assessement of physical law.

The way this makes sense is instead to ponder what physical laws are DISTINGUISHABLE from the poitn of view of say one of the primordal observers? Ie. an electron and a quark might "SEE" different laws of physics, and this might be a key to unification and their mutual interactions or non-interactions.

For example, one could picture that to the primordal observers above a some imagine unification energy, the forces are simply indistinguishable.

This is yet different from the external view of say a human run laboratory.

So this subjective view of evolvtion law by no means threatens the objectivity of HUMAN science.

/Fredrik

 

[Coldcall]

Hi Fra,

Yes i am afraid i don't accept that one particle can "observe" another since it has no relatively complex information processing capabilities. So yes when i talk about observers i mean biological systems which have a) sensors to interpret the physical environment b) information processing ability.

Hence this is why i reject the notion of "decoherence" as anything other than a FAPP construct.

Of course i am biased because my view is that qm is actually a science of "consciousness" or let's say a framework for creating a physical reality, which is not possible without the information processing capabilities found in biological systems.