Ask any question you want about Physics

originally posted by: greenreflections
a reply to: joelr

Interestingly, at the largest scale, your question about the edges of the universe has a similar problem. Spacetime expands slowly on a local scale, like for galaxies and local clusters of galaxies. But galaxies really far away are moving away from us much faster..

But why do you think is that? Space-time expansion should not be different from where we are compare to the most outskirts of cosmos if we assume space-time expands equally from every point of it, imo.
Why space-time locally expands slower than we clock expanding distant galaxies especially when it is thought that expansion must be faster than light by now to accommodate calculations? The Moon should be getting further away from the Earth). Or, are there special areas of space-time where expansion more preferable?


thanks)


Reason: correction/ the Moon IS getting further away from the Earth/

Right I know what you mean but the reason is because the expansion is accumulative. So if you break it up into light year chunks then the light year of space around us is expanding only a tiny amount. But the second light year is also expanding a tiny amount so from our perspective there is our tiny expansion plus the second light years expansion so that 2nd light year ends up moving away a little faster.
It's really only noticeable on a much larger scale, eventually all the tiny amounts add up to a very fast expansion. But from our frame it's the space chunks that are very far away. The further you go the more tiny amounts get added up.

If you actually WENT there everything would seem normal, just like being here - no extreme expansion. You would see expansion only when looking out into deep space.

If expansion continues to get faster then eventually it will become noticeable on smaller scales or closer-to-us scales. Right down to planets and then even particles. That's what that term "The Big Rip" means.

I think the Moon moving away is just part of what's going on with gravity and energy transference rather than expansion.

a reply to: greenreflections
The answer wasn't worded that well and you're also making some additional false assumptions. The answer should have said "recessional velocities of galaxies closer to Earth are smaller" not "Spacetime expands slowly on a local scale". Since the most recent observations are closest to Earth and the expansion of the universe is accelerating, spacetime doesn't expand more slowly on a local scale, just the opposite, though it's really viewed by cosmologists as a time scale rather than a distance scale, which happen to coincide from our viewing point on Earth.

The expansion isn't the same everywhere we look. Hubble's law says the velocities of various galaxies receding from the Earth are approximately proportional to their distance from the Earth for galaxies from about 30 million light years away to maybe a billion light years away, and we refer to a "Hubble constant" in this range so you could say within that distance range the expansion seems somewhat uniform. However, 1998 we discovered the expansion of the universe is accelerating so now we know it's not constant at all distances/times (note the cosmological link between the distance of the observation and the time of the observation, the further something is the longer back in time the observation). Conversely if expansion was the same everywhere we wouldn't be able to report that the expansion of the universe is accelerating, as noted in these two papers:

arxiv.org...
arxiv.org...

For the nitty-gritty details of how expansion varies with the observation distance, you can read those papers.

On the scale of a galaxy and smaller, the effects of the metric expansion of space may not be precisely zero but they tend to be negligible, meaning if you treat them as zero, you're still going to get the same answer you'd measure in observations. The difference would be difficult to measure.

the Moon IS getting further away from the Earth

Yes, because of tidal interaction, not because of the metric expansion of space.

www.thenakedscientists.com...

whether the pull of gravity, or the push of dark energy dominates over a given region of the universe, depends on how much mass is there, and how widely separated it is. If they're far apart, the push of the dark energy wins, but if they're close together, gravity is going to dominate.

The Earth and the moon are close enough together so that gravity dominates. Actually even at 2 million light years away, gravity seems to dominate the movement of the Andromeda Galaxy and other galaxies in the local group, which is why we don't really observe Hubble's law applying at distances less than about 30 million light years; Our "local group" of galaxies has a fair amount of gravity and are not that far apart as cosmic distance scales go.

At the very top of this thread, things started with the philosophy behind quantum mechanics. I was privileged to attend a talk by the great John Stewart Bell back when I was a professor of physics at UCLA in the late 80's. In his talk, he mentioned one of the difficulties of the Copenhagen interpretation of quantum mechanics, as he dwelt on the issue of exactly when does the observer collapse the wave function of what is being observed? He asked: Is I when the light hits my spectacles, or my eyes? I thought for quite a while about that issue, and came up with the belief that the collapse of the wave function occurs when the entity itself interacts with any other entity. When it does so, it either collapses to a size given by hbar divided by the momentum transfer, or to any region still allowed where no momentum transfer is required. I published this in one of my papers in Physics Essays, but I don't know that it ever got any significant audience.

a reply to: delbertlarson
Thanks for contributing your comments to this thread. By any chance did you watch the video in the opening post by Sean Carroll? He talks about different ideas about collapse and explains that his preferred Everett interpretation has no collapse.

I have no idea how to determine if his preferred idea from Everett is right or wrong, or if your idea that there actually is collapse is right or wrong since it appears the different ideas mentioned by Carroll in that video can't yet be sufficiently tested in experiments to resolve which idea is correct.

Of course Bell did make a significant contribution by providing his inequality tests which could be performed. Maybe we need another person like him come along and propose some new experiments which can help answer some of the remaining questions about decoherence and whether the wave function collapses or as Sean Carroll suspects, if there is no collapse because collapse is not part of the Everett interpretation.

If no experiments can distinguish between these different ideas, I try to avoid taking a strong preference for any of them based on personal bias. If I were to do that I'd have to say I'm biased against the many worlds interpretation because I'm not a fan of all those universes but my bias may not be a good enough reason to reject the idea.

a reply to: Arbitrageur

Thank you for your reply. It has been decades since I have gotten into this topic, and it is fun to consider it again.

I must admit that I had only watched the first couple minutes of the video at the top of this thread before I commented the first time. After you kindly asked, I went ahead and watched it in full. While I would say Carroll raises many good questions, and has some reasonable partial answers, my bias remains what I posted above. The main point being that wave functions really exist, that physical entities have a density given by the square of the wave function, and when those entities interact that wave function collapses according to what I mentioned above. This view of things does away with the enormous number of universes needed by the many world approach, and it also separates out "observation" from mere "interaction". In what I propose, the whole problem of the cat being half dead and half alive is no longer an issue, since it is the interaction of the radioactive product breaking the vial that is the cause for the wave function to collapse in that case. It also is a simple answer to Bell's query about whether the observation is in his spectacles, eyes or brain that causes the collapse, since the answer in my view is that it is the exchange of momentum in an interaction that initiates the collapse - the collapse is triggered by inanimate interaction; it has nothing to do with observation from a sentient being.

However, I would say that your point is extremely well taken. The issue is what do the various interpretations say about what experiments can be done. That is science. We should reduce the interpretations to produce different predictions about experiments, and then use those experiments to enlighten us as to which interpretation is superior.

What much of the discussion has centered on though is philosophy, and there Occam's razor is something I think useful. I would defend my bias on that grounds, but I will readily admit that my bias is then centered on philosophy, not science.

One final point for now is that I was thrown a bit of a curve in that I had always read about the many worlds approach being accredited to Wheeler, not Everett. In doing a bit of research I learned that Everett was a student of Wheeler, so that is likely where the confusion set in.

a reply to: delbertlarson

My opinion (and I think it was Schroedinger's as well) is that collapse and locality is an emergent phenomenon in the limit of large particle number. "Interaction with measurement equipment", means interaction with a very large number of atoms in a macroscopic measurement apparatus which is thermodynamically irreversible.

Schroedinger's Cat was his hypothetical, a naive application of Copenhagen brought to its absurd limit.

Anyway, the experiments today do show that something---whatever that is---happens non-locally and we had better get used to it, but that there is no superluminal transmission of macroscopically useful (i.e. to people) information.

And I'll agree with you: wavefunctions are as physically real as electromagnetic fields, and that collapse is a physical process, and it doesn't require consciousness or anything else. And I think we will eventually find it right there in the Heisenberg equation of motion---or maybe in the 2nd quantization of field theory: www.researchgate.net...

I've read some paper (can't find it now) that showed that even an extremely small nonlinearity can grow exponentially like the sensitivity to initial conditions in chaos and appear to generate irreversible collapse. This may mean that it doesn't even matter what the mechanism of that nonlinearity is---anything will do. Quantum gravity, field theory, extra galactic neutrinos, whatever. Consciousness not needed.

Copenhagen interpretation is a useful heuristic, the way that Fermi's golden rules are useful approximatinos to the underlying computations of perturbation theory, but it's a simplified heuristic for most ordinary experimental setups, but not deep TRVTH, as seen by the fact that it doesn't really make sense when you think about it more carefully.

And Einstein thought about it more carefully and believed it to be incomplete. I think his diagnosis was right.

His proposal turned out to be wrong, but experiments showing it to be wrong weren't available until after his death.

BTW, on the Einstein vs Bohr "League Table": Neils Bohr didn't believe that stimulated emission was possible. So on lasers, Einstein wins a clear point. QM interpretation, I think current results shows it's a draw, and not a Bohr victory as traditionally believed.

a reply to: mbkennel

Thanks so much for your reply.

I am not sure what "emergent phenomenon in the limit of large particle number" means. I do think I can be a bit more clear myself though on what I mean by discussing this topic in terms of my favorite example - the two slit experiment.

In the two slit experiment, light is impinged upon a barrier containing two slits. If a quanta of light interacts with the solid part of that barrier, it shows a small speck of a dot as that portion of the light is scattered from its point of interaction. My view is that the wave function for that particular photon that hit the barrier is collapsed to a size of dx = hbar/dp, where dp is the momentum exchanged when the photon hit the solid barrier.

But for other photons that instead penetrate the slits, since there is no momentum transferred at all, and the wave function is then able to occupy both slits, but only the slits. (It can't exist at the solid part of the barrier or it would interact there.) After the slits the two portions of the photon travel to the distant wall. At the distant wall there are no open spaces and so an interaction is demanded. And the probability of the interaction happening at any point on the distant wall is determined by the square of the wave function there. This indeed is the interference pattern observed when many such photons are allowed to go through the two slits. But when any one photon hits the wall, it again shows the same speck of light that has a size of dx = hbar/dp.

I retain my belief that this interpretation of things is the simplest one we can have, and it doesn't have any of the hocus-pocus associated with competing quantum mechanics interpretations.

The above does however have a problem with relativity. The collapse of the wave function at that distant wall must happen in such a way that distant parts know that it is collapsing, or else it could begin to collapse in two places. And this action-at-a-distance is something relativity doesn't allow. Then again, tests of Bell's theorem have also shown actions at a distance contrary to the special theory. So I still prefer this very simple interpretation of quantum mechanics.

Some cool

www.gifbeam.com...

i.imgur.com...

originally posted by: delbertlarson
a reply to: mbkennel

Thanks so much for your reply.

I am not sure what "emergent phenomenon in the limit of large particle number" means.

Where do Navier-Stokes equations and the phenomenon of fluid mechanics come from? If you looked at the Standard Model, would you find it? Not obviously so, yet fluid mechanics is a robust and common phenomenon.

That's my analogy.

I do think I can be a bit more clear myself though on what I mean by discussing this topic in terms of my favorite example - the two slit experiment.

In the two slit experiment, light is impinged upon a barrier containing two slits. If a quanta of light interacts with the solid part of that barrier,

I.e. charged particles in atoms

it shows a small speck of a dot as that portion of the light is scattered from its point of interaction. My view is that the wave function for that particular photon that hit the barrier is collapsed to a size of dx = hbar/dp, where dp is the momentum exchanged when the photon hit the solid barrier.

But for other photons that instead penetrate the slits, since there is no momentum transferred at all, and the wave function is then able to occupy both slits, but only the slits. (It can't exist at the solid part of the barrier or it would interact there.) After the slits the two portions of the photon travel to the distant wall. At the distant wall there are no open spaces and so an interaction is demanded. And the probability of the interaction happening at any point on the distant wall is determined by the square of the wave function there. This indeed is the interference pattern observed when many such photons are allowed to go through the two slits. But when any one photon hits the wall, it again shows the same speck of light that has a size of dx = hbar/dp.

I'm not convinced this solves the problem, I believe that is just restating that collapse happens upon interactions (and you define interactions operationally and physically), and doesn't solve the problem when the barrier is also made out of quantum mechanical particles with their own wavefunction. If all of the QM of the Universe is truly linear then there would be nothing to initiate the collapse.

The linked paper says, "Take a look again: the QM of the Universe is actually QFT, and not just the Schroedinger equation. And in there, there's a nonlinearity: you have equations of motion for the wavefunctions (d/dt wavefunction on the left side), but in QFT there are terms which are proportional to the probability densities on the right hand side, i.e. wavefunction squared. And that's a nonlinearity, and nonlinearity can result in the appearance of wavefunction collapse by the equations of motion."

To me, that's a pretty minimal physically plausible theory that doesn't require any philosophical mumbo jumbo or infinite universe: integrate the correct equations of motion, and wavefunctions collapse because that's what they do. It's basically classical physics as Newton would understand it, albeit in functional space.

Certainly from a nonlinear dynamics point of view adding even a small nonlinearity can radically change the nature of solutions---forget even QM, just in classical dynamics and ODE's. You can go from conservative systems with superposition (boring) where all frequencies on initial conditions stay forever, to nonlinear systems with chaos and attractors and dynamics which preferentially pick out one of a number of terminal 'fixed points', the choice of which cannot be predetermined in practice since it is an amplification of infinitesimal fluctuations.

I retain my belief that this interpretation of things is the simplest one we can have, and it doesn't have any of the hocus-pocus associated with competing quantum mechanics interpretations.

Is it different than the 'shut up and calculate' Copenhagen interpretation?

The above does however have a problem with relativity. The collapse of the wave function at that distant wall must happen in such a way that distant parts know that it is collapsing, or else it could begin to collapse in two places. And this action-at-a-distance is something relativity doesn't allow.

IF, your underlying theory is composed of differential equations (only, no integral equations) on fields in 4-d space time, say like general relativity or acoustics or classical electromagnetism (i.e. a classical field theory) then adding relativity precludes nonlocality.

The equations of motion of QM are not such a theory. Everything weird is because the true state is in an incomprehensible functional Hilbert space. Relativity in actual practice means asserting that certain transformation axioms & symmetries are preserved, which is the case for relativistic QM.

Then again, tests of Bell's theorem have also shown actions at a distance contrary to the special theory.

I think we should start believing the experimental results in front of our eyes. Something deep in the wavefunction/functionalspace/matrix can happen non-locally, and we need to accept that as physical truth. And likewise, something in QM also seems to prevent nonlocal classical information transfer, so that we will not be able to exploit this nonlocality macroscopically for paradoxical and amazing purposes.

a reply to: mbkennel

You mentioned a lot in your last reply, and it got me thinking. Thanks. I will try to clarify my position a bit more here. This reply will touch upon many of the topics of your last reply, but not all of them, as I don't want to try to have too large a scope in this single post.

I retain my belief that the essence of the quantum mechanical mystery is found in the simple two slit experiment, and I also retain my belief that my earlier post helps to understand that mystery in a way that can be grasped by the human mind. I will try to reformulate my view into a few postulates:

Postulate 1 - Any interaction between entities causes the original participating quantum states to collapse into one of the possible resultant quantum states available to them at the time of the interaction.

Postulate 2 - The probability of a collapse into any particular resultant quantum state is the square of the original wave function's normalized magnitude appropriately integrated over that particular resultant quantum state.

Postulate 3 - When momentum is transferred in a collapse, the quantum state will collapse to a size dx=hbar/dp, where dp is the momentum transferred.

For the photon impingent upon the two slits in the two slit experiment, the resultant possibilities include collapsing to the entirety of the two slits, or collapsing to any single spot on the barrier. This is different from the Copenhagen interpretation in that no sentient observer is needed. The collapse does not occur because of an observation as in Copenhagen; instead it occurs because a choice is forced upon the original quantum state to become one of several possible resultant quantum states. This choice is forced by the existence of the barrier and walls and has nothing to do with an "observation".

In your reply you bring up the wave function of the barrier. In my simple view, the wave function of the barrier isn't all that important. That is because I believe that each particle in the barrier primarily has its own wave function, largely uncoupled from the other particles constituting the barrier. But more importantly, I believe the impinging photon is, for all practical purposes, totally uncoupled from the particles of the barrier until the collision occurs. This allows us to confine our focus to the photon wave function alone, along with what happens to it, and not be concerned about other wave functions.

There is an important caveat to the paragraph above. Electrons in the barrier may well have some quantum mechanical coupling with other electrons of the barrier, since the single electron can have some probability distribution overlap with other electrons of the barrier. For an individual nucleus though, its wave function is quite independent of other nuclei, since its overlap probability with other nuclei is vanishingly small. But in any event, I believe we can fully isolate the impinging photons from the barrier and wall in our analysis until interaction occurs.

If we do wish to look into the barrier at the moment of collision, the question becomes: what does the photon collide with? I would postulate that it collides with a single electron of the barrier, and that the single electron involved also becomes collapsed to a size of dx=hbar/dp at the time of the interaction. But since the electron is part of an atomic state, it may already be confined to that size or even less, so the collision has very little effect even on that electron, let alone the barrier as a whole. Note that which electron is chosen is simply one of the possible resultant quantum states, and that any of the electrons may play that role.

If we instead attempt to concern ourselves with the wave function of the entire universe I believe things get so complex that we will never make any progress at all. And that is why my focus has always been on the wave function of the single photon, and why I choose to treat the barrier and ultimate wall as separate entities here.

Within my view the photon consists of electric and magnetic fields which obey Maxwell's equations. Maxwell's equations are linear equations that lead to the wave equation for the substituent magnetic and electric fields. That simple wave underpinning leads to a density at the distant wall that is in complete agreement with experiment for the many particle result of two slit experiment. I know of no experiment that shows anything incorrect about Maxwell's equations, so I don't see how any nonlinearity will enter in to them. The only issue is how can we understand the collapse, and I believe my postulates above allow for such an understanding. They do not allow for a prediction of where an individual collapse will occur however, and only result in allowing us to understand how such a thing could happen and what non-sentient causes there are for such a collapse.

originally posted by: delbertlarson
a reply to: mbkennel

You mentioned a lot in your last reply, and it got me thinking. Thanks. I will try to clarify my position a bit more here. This reply will touch upon many of the topics of your last reply, but not all of them, as I don't want to try to have too large a scope in this single post.

I retain my belief that the essence of the quantum mechanical mystery is found in the simple two slit experiment, and I also retain my belief that my earlier post helps to understand that mystery in a way that can be grasped by the human mind. I will try to reformulate my view into a few postulates:

Postulate 1 - Any interaction between entities causes the original participating quantum states to collapse into one of the possible resultant quantum states available to them at the time of the interaction.

This is the orthodox von Neumann axiom---when at least one "entity" is a classical thing called a measurement device. Which makes that QM a theory of quantum particles interacting with non-quantum stuff outside QM.

Otherwise, if they are both quantum particles, then this isn't true---an entangled state is exactly a mutually interacting one of profoundly quantum entities which haven't collapsed, and this phenomenon is experimentally real.

Postulate 2 - The probability of a collapse into any particular resultant quantum state is the square of the original wave function's normalized magnitude appropriately integrated over that particular resultant quantum state.

Yes, sure, is this different from | [final_state | Interaction | initial_state]|^2 ?? Wouldn't think so.

That's pretty much the operational definition of "an experiment" in QM.

Postulate 3 - When momentum is transferred in a collapse, the quantum state will collapse to a size dx=hbar/dp, where dp is the momentum transferred.

Seems reasonable, but do you believe collapse can happen only with transfer of momentum? What about a flavor changing weak interaction? (to pick up on something exotic at random).

For the photon impingent upon the two slits in the two slit experiment, the resultant possibilities include collapsing to the entirety of the two slits, or collapsing to any single spot on the barrier. This is different from the Copenhagen interpretation in that no sentient observer is needed.

Does Copenhagen require this?

The collapse does not occur because of an observation as in Copenhagen; instead it occurs because a choice is forced upon the original quantum state to become one of several possible resultant quantum states. This choice is forced by the existence of the barrier and walls and has nothing to do with an "observation".

I think this operationally means interaction with a classical barrier.

In your reply you bring up the wave function of the barrier. In my simple view, the wave function of the barrier isn't all that important. That is because I believe that each particle in the barrier primarily has its own wave function, largely uncoupled from the other particles constituting the barrier. But more importantly, I believe the impinging photon is, for all practical purposes, totally uncoupled from the particles of the barrier until the collision occurs. This allows us to confine our focus to the photon wave function alone, along with what happens to it, and not be concerned about other wave functions.

Exactly---until the timescale of substantial interaction. I think we may be in agreement---interaction with stuff which has 10^23 QM particles causes the appearance of collapse, and it is physical. But there is still more to be solved---how exactly does this happen?

If we instead attempt to concern ourselves with the wave function of the entire universe I believe things get so complex that we will never make any progress at all.

Operationally of course, but the philosophical problem is there---if QM is fully linear then you get multiple universes in effect.

And that is why my focus has always been on the wave function of the single photon, and why I choose to treat the barrier and ultimate wall as separate entities here.

I think that's a mistake in solving the mystery of collapse which is exactly problem in question.

Suppose somebody could simulate interaction of one QM particle with a 'measurment device' of (e.g.) 100 QM particles?

I bet if somebody could do a proper simulation, there would be some transition in which 'no collapse' to 'collapse' takes place. This has almost surely been done already---it may be regarding the 'decoherence'.

But decoherence gets you most of the way, but it doesn't get you all the way to collapse.

Within my view the photon consists of electric and magnetic fields which obey Maxwell's equations.

Well, the QFT state which is a wavefunction over the E & B fields, i.e. a function over a function, and a photon is a eigenstate of an operator in the QM wavefunction (which means that in many bases it is not a pure state in E & B fields).

Maxwell's equations are linear equations that lead to the wave equation for the substituent magnetic and electric fields. That simple wave underpinning leads to a density at the distant wall that is in complete agreement with experiment for the many particle result of two slit experiment. I know of no experiment that shows anything incorrect about Maxwell's equations, so I don't see how any nonlinearity will enter in to them.

There isn't any in Maxwell's equations. There is in QED.

The only issue is how can we understand the collapse, and I believe my postulates above allow for such an understanding. They do not allow for a prediction of where an individual collapse will occur however, and only result in allowing us to understand how such a thing could happen and what non-sentient causes there are for such a collapse.

A goal is to derive physics that explains the results which don't need any collapse postulate. That's a "P" projection operator introduced by von Neumann, but is really outside the normal operation of QM. (i.e. 'who puts it in' and when?) Great approximation to experimental observations, but not the underlying theory.

Here's my postulate and the one advocated by the paper I quoted:

There are no necessary postulates about collapse. If one were to integrate the right equations of motion for the quantum field theory, including particle and measurement device, collapse happens as a chaotic dynamical phenomenon. In this view "God does not play dice with the universe", other than it being like real physical dice (i.e. sensitive dependence on initial conditions). Einstein's discomfort with QM of 1930 was justified.

originally posted by: mbkennel
Something deep in the wavefunction/functionalspace/matrix can happen non-locally, and we need to accept that as physical truth. And likewise, something in QM also seems to prevent nonlocal classical information transfer, so that we will not be able to exploit this nonlocality macroscopically for paradoxical and amazing purposes.

I believe the weirdness has to do with at least either hidden fields and/or Earths complex multiple movements;

Hidden fields; Imagine you were in a pool of crystal clear water and there was a camera above you that due to focus and/or aperture and/or resolution and/or other reasons could not detect the water at all, and there was a floating ball at some distance to you, and so the camera detects that you move your hands around (in the water) and the ball moves (spooky action at a distance).

And/or (combined) with Earths complex multiple movements (if the milky way is moving relative left or right or up or down from a real position it formally occupied; besides revolution of stars and planets around the center, but as a system, stars and planets and center moving relative etc.) Earth moving linearly through ultimate absolute space time via aforementioned milky way as a system moving (unless you believe the center remains absolutely fixed point still and ignoring all else beyond the milky way, the milky way is a fixed point carousal or fixed point whirlpool with a center which stars and planets revolve around); Earth revolving around central black hole; Earth revolving around Sun; Earth rotating;

The result of these multiple movements, along with not fully known and understood fields, plus potentially hidden fields (though maybe all that is hidden is that which is not fully known about the fields that are known) and then the big plus of ill thought theory; results in any contradictory, paradoxical, a priori eternally impossible concepts or weirdnesses that show up in theory and early stage imperfect experiment.

Considering those continuous multiple movements of Earth, while considering the possibility that a single aspect of Earths movement might effect the gravity field (might effect all local fields) let alone all of Earths movements let alone the suns movements and milky ways movements as well;

Think, about an individual turning on a flashlight while standing on Earth. I tried to draw what I am attempting to get at but failed. But I thought I might have finally realized what the thinking behind many worlds is, but no now that I think of it I think I may be just describing relativity;

I tried to draw a blue circle, rotating (an N and S slowly changing each 'frame' like clock frame 1 N is 12 oclock frame 2 N is 1 etc.) (as well as indicating reminder of the earths other Movements)

And then in a frame the flashlight is turned out;

These multiple motions of Earth are continuous; and the light of the flash light is relatively continuous?

From our reference frame we might see a straight beam, continuously; but from an absolute reference frame it would be seen like a stepping effect, wall/incline? of light?

And then considering how gravity material might also be rotating and moving how that light may interact with such locally and beyond;

So I just thought it was neat to think of that, how because movement is continuous, events might have some blur effect

And also, how potentially where an event occurs on the earth in relation to all of its movements, how because Earth is moving forward and rotating, how detection or event can 'run into it', making potentially the quantum 'weirdness' possibly a result of a type of cosmically ironic (at least for those skeptical of those confident in realism and paradoxical oddity) 'tossing into the wind'.

I understand a large reason for confusion may be intentional misleading by the gatekeepers whom you may be a part of; but for starters, a question relevant to the topic of quantum weirdness and the belief in Bells theorem; what is even meant by a 'photon being split into a pair'?

From what I have seen on this thread of EM and photon, I have never seen anything that would suggest what has been explained and described as EM and photon physical mechanical nature, a single quanta of photon can be split into two.

But I guess this has to do with most fundamentally EM and photon being more wave like than particle like; the only concept and aspect of particle like is that the wave at any given time is not infinitely large; like if I drop a rock in a pond it does not make infinite waves, so from the first wave to the last wave of the event, is called a particle, or wave packet.

So splitting a photon, means altering the wave, I suppose. With this understanding I suppose I can revisit the quantum weirdness thoughts with Bells theorem.

originally posted by: ImaFungi

originally posted by: mbkennel
Something deep in the wavefunction/functionalspace/matrix can happen non-locally, and we need to accept that as physical truth. And likewise, something in QM also seems to prevent nonlocal classical information transfer, so that we will not be able to exploit this nonlocality macroscopically for paradoxical and amazing purposes.

I believe the weirdness has to do with at least either hidden fields and/or Earths complex multiple movements;

Hidden fields; Imagine you were in a pool of crystal clear water and there was a camera above you that due to focus and/or aperture and/or resolution and/or other reasons could not detect the water at all, and there was a floating ball at some distance to you, and so the camera detects that you move your hands around (in the water) and the ball moves (spooky action at a distance).

Nope, Bell's inequalities and other experiments rule this general sort of thing out for causing collapse. Pilot Wave theory is an alternate reformulation of standard QM.

And/or (combined) with Earths complex multiple movements (if the milky way is moving relative left or right or up or down from a real position it formally occupied; besides revolution of stars and planets around the center, but as a system, stars and planets and center moving relative etc.) Earth moving linearly through ultimate absolute space time via aforementioned milky way as a system moving (unless you believe the center remains absolutely fixed point still and ignoring all else beyond the milky way, the milky way is a fixed point carousal or fixed point whirlpool with a center which stars and planets revolve around); Earth revolving around central black hole; Earth revolving around Sun; Earth rotating;

Totally irrelevant to QM collapse.

The result of these multiple movements, along with not fully known and understood fields, plus potentially hidden fields (though maybe all that is hidden is that which is not fully known about the fields that are known) and then the big plus of ill thought theory; results in any contradictory, paradoxical, a priori eternally impossible concepts or weirdnesses that show up in theory and early stage imperfect experiment.

Considering those continuous multiple movements of Earth, while considering the possibility that a single aspect of Earths movement might effect the gravity field (might effect all local fields) let alone all of Earths movements let alone the suns movements and milky ways movements as well;

Think, about an individual turning on a flashlight while standing on Earth. I tried to draw what I am attempting to get at but failed. But I thought I might have finally realized what the thinking behind many worlds is, but no now that I think of it I think I may be just describing relativity;

I tried to draw a blue circle, rotating (an N and S slowly changing each 'frame' like clock frame 1 N is 12 oclock frame 2 N is 1 etc.) (as well as indicating reminder of the earths other Movements)

And then in a frame the flashlight is turned out;

These multiple motions of Earth are continuous; and the light of the flash light is relatively continuous?

From our reference frame we might see a straight beam, continuously; but from an absolute reference frame it would be seen like a stepping effect, wall/incline? of light?

And then considering how gravity material might also be rotating and moving how that light may interact with such locally and beyond;

So I just thought it was neat to think of that, how because movement is continuous, events might have some blur effect

And also, how potentially where an event occurs on the earth in relation to all of its movements, how because Earth is moving forward and rotating, how detection or event can 'run into it', making potentially the quantum 'weirdness' possibly a result of a type of cosmically ironic (at least for those skeptical of those confident in realism and paradoxical oddity) 'tossing into the wind'.

I understand a large reason for confusion may be intentional misleading by the gatekeepers whom you may be a part of; but for starters, a question relevant to the topic of quantum weirdness and the belief in Bells theorem; what is even meant by a 'photon being split into a pair'?

From what I have seen on this thread of EM and photon, I have never seen anything that would suggest what has been explained and described as EM and photon physical mechanical nature, a single quanta of photon can be split into two.

No, but a photon can interact with charges, be absorbed and the charges emit two photons. There is no strong conservation law on number of photons, unlike with most material particles which are very hard to convert from one into another at normal energies.

a reply to: mbkennel

Here is an example of the exact simulation that I was thinking about!

arxiv.org...

A minimally nonlinear von Neumann equation for a Stern-Gerlach or Bell-type measuring apparatus, having a scalar product structure over the configuration space, i.e. a sum of locally acting terms, is shown to display a competition for survival between diagonal density matrix elements assigned to each detector combination, with a single winner randomly selected according to Born's rule and the rest collapsing to zero. Randomness is emerging from deterministic-chaotic dynamics of the detectors, their microscopic states acting as a nonlocal set of hidden parameters, controlling individual outcomes. The scheme works without any kind of action-at-a-distance; still it is fully reproducing quantum behavior, which warrants it is non-signaling.

A minimal physically realistic but potentially very small nonlinearity can make wavefunctions collapse and derive the Born rule as a phenomenon instead of an axiom.

originally posted by: mbkennel

A minimal physically realistic but potentially very small nonlinearity can make wavefunctions collapse and derive the Born rule as a phenomenon instead of an axiom.

What is the minimal definition/requirement of the term 'nonlinearity'? And can you provide a simple real or thought experimented example?

What was the confusion discussed above regarding QM collapse?

originally posted by: mbkennel
Does Copenhagen require this?

I'm having fun reading the discussion. There is some confusion over the word "observer" and it's sometimes misunderstood to refer to consciousness in Copenhagen, but it doesn't require a sentient observer according to Heisenberg and I'm sure he's not the only one who would say so. In fact we have experiments to show the "collapse" doesn't require the information to be made available to a conscious observer, so if Copenhagen really inferred that we would have to stop teaching it and teach something else.

Physics and Philosophy - Werner Heisenberg pdf p 60-61

It is the `factual' character of an event describable in terms of the concepts of daily life which is not without further
comment contained in the mathematical formalism of quantum theory, and which appears in the Copenhagen interpretation by the introduction of the observer. Of course the introduction of the observer must not be misunderstood to imply that some kind of subjective features are to be brought into the description of nature. The observer has, rather, only the function of registering decisions, i.e., processes in space and time, and it does not matter whether the observer is an apparatus or a human being; but the registration, i.e., the transition from the `possible' to the `actual, ' is absolutely necessary here and cannot be omitted from the interpretation of quantum theory.

By the way the double- slit quantum eraser experiment and the double- slit delayed choice quantum eraser experiment are harder to explain with some of the simpler explanations.

originally posted by: ImaFungi

originally posted by: mbkennel

A minimal physically realistic but potentially very small nonlinearity can make wavefunctions collapse and derive the Born rule as a phenomenon instead of an axiom.

What is the minimal definition/requirement of the term 'nonlinearity'? And can you provide a simple real or thought experimented example?

There is a slight invalidation of superposition. Superposition says taht the time evolution of an average of two wavefunctions is the average of the time evolution of each of the two.

d/dt (wavefunction) = LinearOperator on wavefunction

d/dt (wavefunction) = Linear Operator on wavefunction + small_coefficient * (wavefunction | interaction | wavefunction)

the second one is nonilnear as there's a square of wavefunction on the RHS

a reply to: mbkennel

Lots to respond to again. Here are some thoughts:

Otherwise, if they are both quantum particles, then this isn't true---an entangled state is exactly a mutually interacting one of profoundly quantum entities which haven't collapsed, and this phenomenon is experimentally real.

I agree that entangled states complicate things. One reason I focused on the two slit experiment in my comments here is so that we don't have to deal with such complications. That way, I think we can focus on the essence of the confusion, in an attempt to clarify things. My goal here has been to present a philosophical approach that does not involve what I consider to be wild speculations (such as multiple universes or the role of observers) and yet show how things can be at least understood. As stated earlier, it is really relativity that precludes my simple understanding from being accepted, at least for the two slit case. EPR set up a contest between quantum mechanics and relativity, Bell refined the argument, and quantum mechanics won. But rather than setting aside relativity, it was discovered that EPR relied on an assumption of an underlying objective reality, and then objective reality was called into question. Really, it is relativity that should be set aside. Lorentz's theory should be reconsidered.

Seems reasonable, but do you believe collapse can happen only with transfer of momentum? What about a flavor changing weak interaction? (to pick up on something exotic at random).

In the case where the photon does not transfer momentum to the barrier containing the slits, I maintain that the wave function collapses to the entirety both slit regions. (Provided they were overlapped by the original wave function.) So the collapse occurs to both slit regions even though there has been no momentum transfer in that case. In that case, since momentum transfer would have been required if the photon collapsed anywhere in the remainder of the barrier, the collapse occurs to the complete regions where no momentum transfer is required. I don't know how such a proposal affects your non-linearity arguments. Do your arguments work when a single photon has a wave function in two separated areas? Of course, weak interactions do transfer momentum, for instance in neutron decay, momentum gets transferred from the neutron to the proton, electron and neutrino as a result of the decay.

Does Copenhagen require this?

I don't know that Copenhagen requires an "observer". I do know that Bell spent a lot of time on that idea, and that it was flourishing for a while some decades ago. I felt it was one of those wild speculations I find unappealing. I note that Arbitrageur has pointed out that Heisenberg didn't feel the need for an "observer" so perhaps Copenhagen really doesn't need one.

Operationally of course, but the philosophical problem is there---if QM is fully linear then you get multiple universes in effect.

I would say there are infinite (or at least a lot) of particles and/or wave functions within one universe, not multiple universes, even in the case of fully linear QM.

Here's my postulate and the one advocated by the paper I quoted

I've started working through your paper. I find it interesting and worthy of respect. It will require some study, and may take time to digest. I do plan on taking notes my second time through it and plan to post my thoughts about it on this thread.

"God does not play dice with the universe"

Then how does He exercise His will? (Or let us exercise our will?)

And really, philosophically, this may be where you and I depart. If there are no dice, everything is pre-determined and we are merely a conglomeration of wave functions all heading to our fate - we have nothing to say about it. Choice is merely an illusion. Our thoughts - just an illusion. Your and my discussion here - predetermined by some initial conditions established billions of years ago.

I don't believe it.

Instead I believe there must be some random aspect to physics - truly random - so that free choice can exist. A non-determinative quantum mechanics collapse mechanism can provide that randomness, and provides for the physical underpinning of what is commonly known as the soul. It makes choice possible.

originally posted by: delbertlarson
I don't know that Copenhagen requires an "observer". I do know that Bell spent a lot of time on that idea, and that it was flourishing for a while some decades ago. I felt it was one of those wild speculations I find unappealing. I note that Arbitrageur has pointed out that Heisenberg didn't feel the need for an "observer" so perhaps Copenhagen really doesn't need one.

As I said there's a lot of confusion on this issue, but I need to clarify further. Heisenberg not only feels there is a need for an observer in Copenhagen, he says it is absolutely essential. The confusion which ensues is a result of people inferring that "observer" implies a "conscious observer" and Heisenberg is very clear this is not the case when he says "it does not matter whether the observer is an apparatus or a human being" per the above citation.

Instead of saying there must be an "observer" it might be less confusing to say there must be an "interaction of quantum systems". Since an apparatus or other "observer" can play such a role of interaction it's not a conflicting idea. However it's not as catchy to use 4 words instead of one, even if the one word "observer" has confusing connotations about a conscious observer.