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Einstein and "spooky actions"

PolyHedral

Superabacus Mystic
No. It's just a simplified description of the delayed-choice experiment (which is already a simplified thought experiment). Actual experimental set-up is far more complicated.

The point, now empirically confirmed, is that you can set-up an experiment such that you can choose, after the experiment is finished, what the results will be.
Well, yes, but people are trying to interpret those results with very ill-fitting models, i.e. that whatevers are real-valued waves or particles.
 

LegionOnomaMoi

Veteran Member
Premium Member
Well, yes, but people are trying to interpret those results with very ill-fitting models, i.e. that whatevers are real-valued waves or particles.

I'm not sure (again) I understand you (ill-fitting models?), but typically there is a lot less "interpretation" and a lot more "description". I use the scare quotes because the latter is difficult to provide without at least seeming to be the former. That's why when most people talk about these experiments, they may leave out the methods/procedures aspect. However, reading the research is an entirely different matter. Unlike experiments in the social and behavioral science, where many PhDs will perhaps skim the methods section but will concentrate on the abstract, intro section, and discussion/conclusion section or sections. You can't really get away with this in quantum physics research. That is, the description part is necessarily interpretive in that it is pretty hard not to describe the results without using words which give the reader a sense of what the results mean. So it is extremely important for those who want to understand the findings to read the methods section(s).

Also, in the social and behavioral sciences, I've found reading the methods section is usually incredibly depressing. The worst of late was the Colin Firth neuroscience study "Political Orientations Are Correlated with Brain Structure in Young Adults". The authors state "Subsequently, we performed diffeomorphic anatomical registration through exponentiated lie algebra in SPM8 for intersubject registration of the grey matter images", which sounds really impressive as long as you don't know that what they actually did: use a programmed add-on to their neuroimaging software (SPM) called DARTEL: "DARTEL stands for Diffeomorphic Anatomical Registration Through Exponentiated Lie algebra". It may not use a true Lie Algebra, but the acronym is a nice one." Basically, they followed a procedure of laid out in the SPM manual that amounted to clicking a few buttons, but that doesn't sound sciencey enough so among other god-awful methods they used they decided not to use the acronym but claim to have used a Lie algebra in their analysis even though they didn't.

But I digress (because I have become so hateful of most social and behavioral research studies and this was too much to handle). Back to actual scientists.

QM has a great mathematical model. And it is this which allow studies like the following (I'm giving you the arXiv versions which I haven't read, but generally speaking there isn't much of a difference between the pre-prints and the published versions at least in studies like these):
Experimental delayed-choice entanglement swapping

Extreme nonlocality with one photon

Experimental Realization of Wheeler's Delayed-Choice Gedanken Experiment

NMR implementation of a quantum delayed-choice experiment

A Quantum Delayed-Choice Experiment


Of course, it's important to keep in mind that quantum physics is actually completely made-up. In reality, the two "clouds" Lord Kelvin mentioned were solved and the advice Max Planck got about not going into physics (because everything was pretty much wrapped up and solved) was true. But physicists still wanted jobs, so they decided to create QM. Of course, they had to hide their tracks so they invented a new formalism, changed what probability means, talked about states and systems in nonsensical ways, etc., all so that nobody could understand quantum mechanics without going through the initiation process (sort of a cross between the skulls & bones fraternity and the Bayesian conspiracy). After a while, though, everybody had bought it and although they still had to make the papers unreadable, they had fun with the titles:
New Additions to the Schrödinger Cat Family

From Pedigree Cats to Fluffy-Bunnies

Two Atoms Announce Their Long-Distance Relationship

Spooky Action at a Distance or Action at a Spooky Distance

All Tangled up- Life in a Quantum World

and this one was just to see if anybody was paying attention:

Using the Earth as a Polarized Electron Source to Search for Long-Range Spin-Spin Interactions

Alas, few of the studies with cool names or exotically phrased claims involve some implementation of Wheeler's delayed-choice thought experiment. Some are, however, still very interesting.
 
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idav

Being
Premium Member
Well, yes, but people are trying to interpret those results with very ill-fitting models, i.e. that whatevers are real-valued waves or particles.

I've been reading this book named Quantum Enigma *gasps, see I blame you guys for making read lol*. It gives a nice history of the drama between the scientists as they developed the experiments and maths. I've learned a great deal from it and have been able to see a bit more of the problem. There is one things that I noticed that seems to be an issue. QM likes to describe the whole wave function as the particle, photon or electron. The peculiar thing is that when this wave function goes through the the two slits the maths say it is two wave functions and QM likes to see that as two "particles" but this is just abstract for the maths because in reality that photon packet (whatever its supposed to be) only goes through one slit even though its wave function goes through two.

This settles the idea in my head that there is a path traveled despite the maths that help qm make its probability predictions. The delayed choice is just another version of making the particle go a certain route because the detection is collapsing the wave function. Nothing in the experiments can prove the photon packet was in two places except the math. Observation puts the photon in one place which is wherever it happened to be observed thus causing a collapse. What QM can't really say is whether the superposition of the photon is actually the real photon or not. You can't tell until you open the box which is the randomness aspect of QM.

/rant :thud:
 

LegionOnomaMoi

Veteran Member
Premium Member
I've been reading this book named Quantum Enigma *gasps, see I blame you guys for making read lol*.

Dangerous move, that one. Many have entered into the realm of quantum physics, and few have returned to the sun-lit lands. (C. S. Lewis quote I paraphrased).

It gives a nice history of the drama between the scientists as they developed the experiments and maths.


It is designed for the general reader and, better yet, not in the way that e.g., Penrose's book is (which gets into complex analysis in chapter 4 or something and moves on from there).

The peculiar thing is that when this wave function goes through the the two slits the maths say it is two wave functions and QM likes to see that as two "particles" but this is just abstract for the maths because in reality that photon packet (whatever its supposed to be) only goes through one slit even though its wave function goes through two.

Take a closer look at this part (italics in original):
"The waviness in a region is the probability of finding the object in that region. Be careful — the waviness is not the probability of the object being there. There’s a crucial difference! The object was not there before you found it there. Your happening to find it there caused it to be there. This is tricky and the essence of the quantum enigma." p. 75

This settles the idea in my head that there is a path traveled despite the maths that help qm make its probability predictions.

"In quantum theory there is no atom in addition to the wavefunction of the atom. This is so crucial that we say it again in other words: The atom’s wavefunction and the atom are the same thing; “the wavefunction of the atom” is a synonym for “the atom.” Accordingly, before a look collapses a widely spread-out wavefunction to the particular place where the atom is found, the atom did not exist there prior to the look. The look brought about the atom’s existence at that particular place — for everyone."

or
"That’s the crucial point: Each and every atom follows a rule allowing it to land in regions separated by distance “d” in figure 7.10. That rule depends on the box-pair spacing “s.” Therefore, each atom had to “know” the box-pair spacing. According to quantum theory, each atom knows the rule because each atom was in both boxes at the same time...
The most accurate way of describing the state of the unobserved atom is to put into English the mathematics describing the state of the atom before we looked to see where it is: The atom was simultaneously in two states; in the first state, it is in-the-top-box-and-not-in-the-bottom-box, and simultaneously in the second state, it is in-the-bottom-box-and-not-in-the-top-box.
Putting it this way, however, boggles the mind. It’s saying a physical thing was in two places at the same time. The quantum mechanical term for this situation is that the atom is in a “superposition state” simultaneously in both boxes." pp. 78-79



The delayed choice is just another version of making the particle go a certain route because the detection is collapsing the wave function. Nothing in the experiments can prove the photon packet was in two places except the math.

which is the only way we ever prove anything. QM is different in the way the mathematical model relates to the physical system (in that we don't know how it does), but we cannot even explain the basic double-slit experiment if we assume that there is a particle going anywhere. First, because neither particles nor waves can interfere with themselves, and second because particles will never show an interference effect. Yet that's what happens.

It isn't just the math. If you watch that cartoony clip you can see the "particles" going through the slits like we'd expect. Electrons (or photons etc.) no not do this. If they had a definite position, then they'd have a definite trajectory, and we'd have no interference pattern. It's the observations, not the math, that force us to abandon the idea of particles.

The delayed-choice just makes this even more confusing, because it indicates (as the authors state in the quotes above), either the particles aren't anywhere until we look, or are in multiple places.



Observation puts the photon in one place which is wherever it happened to be observed thus causing a collapse.

First, this "collapse" is just a way of saying the system we described as being spread out over space has isn't any more. Second, watch the cartoon video again and compare how particles go through two slits with the interference pattern of two slits. Now let's imagine the impossible: a photon has gone through one slit and is about to show up in one of the spots that can only be explained via interference. Having assumed this, then as soon as it goes through that slit towards that spot we should be able to detect it taking the path to that spot. In fact, if we remove the detection screen right before it hits that spot, it should be right there. It won't be. Even though the photon has already travelled through the double-slit screen, and would (if we left the screen in place), hit a particular spot, if we remove the screen right before it lands, it will be somewhere totally different and (if we imagine that the photon is where the screen was a moment ago) it will be in a spot that we will never detect ever with the screen there.


What QM can't really say is whether the superposition of the photon is actually the real photon or not.

In my previous post I included links to actual experiments. This is a quote from the conclusion of one: "In Wheeler’s words, since no signal traveling at a velocity less than that of light can connect these two events, 'we have a strange inversion of the normal order of time. We, now, by moving the mirror in or out have an unavoidable effect on what we have a right to say about the already past history of that photon'"

The point of the delayed-choice experiment isn't that the photon ends up at a weird location. It's that the only way it can be explained is by positing retrocausation: we have changed how the photon travelled from the double-slit screen after it has already gone through. We are changing its past.
 
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idav

Being
Premium Member
Dangerous move, that one. Many have entered into the realm of quantum physics, and few have returned to the sun-lit lands. (C. S. Lewis quote I paraphrased).
Nice.

It is designed for the general reader and, better yet, not in the way that e.g., Penrose's book is (which gets into complex analysis in chapter 4 or something and moves on from there).
The book talks about how they have a school where they teach this stuff to non-scientists.


Take a closer look at this part (italics in original):
"The waviness in a region is the probability of finding the object in that region. Be careful — the waviness is not the probability of the object being there. There’s a crucial difference! The object was not there before you found it there. Your happening to find it there caused it to be there. This is tricky and the essence of the quantum enigma." p. 75
Yeah I remember reading that and that caused it to click in my head. The test question emphasises, as I have, that it isn't saying it will "be" there but that you might "find" it there. It is tricky but essentially the collapsing of the wavefunction causes the location to be specific. It may or may not have been in a specific path trajectory to the specific location it was found, fo simplicity sake I think it was.

I have read else where that they can do weak measurement by measuring the influenced area after the photon has passed to determine its trajectory after the fact.
"In quantum theory there is no atom in addition to the wavefunction of the atom. This is so crucial that we say it again in other words: The atom’s wavefunction and the atom are the same thing; “the wavefunction of the atom” is a synonym for “the atom.” Accordingly, before a look collapses a widely spread-out wavefunction to the particular place where the atom is found, the atom did not exist there prior to the look. The look brought about the atom’s existence at that particular place — for everyone."
Yes I remember this in the book as well. Which is where it clicked with me that QM treats the wave function literally as the particle. This becomes a problem when the double slit creates two wave functions and a need to call both the literal particle. The book shows the experiments that the photon is both particle and wave. You can do a specific experiment to prove either.
or
"That’s the crucial point: Each and every atom follows a rule allowing it to land in regions separated by distance “d” in figure 7.10. That rule depends on the box-pair spacing “s.” Therefore, each atom had to “know” the box-pair spacing. According to quantum theory, each atom knows the rule because each atom was in both boxes at the same time...

The photon knows based on the physical construction of the experiment. The book does suggest it's possible the physical structure chose it. This leads to the need to say that the photon predicted what the experimenter would do which is ludicrous.

The most accurate way of describing the state of the unobserved atom is to put into English the mathematics describing the state of the atom before we looked to see where it is: The atom was simultaneously in two states; in the first state, it is in-the-top-box-and-not-in-the-bottom-box, and simultaneously in the second state, it is in-the-bottom-box-and-not-in-the-top-box.
Putting it this way, however, boggles the mind. It’s saying a physical thing was in two places at the same time. The quantum mechanical term for this situation is that the atom is in a “superposition state” simultaneously in both boxes." pp. 78-79
In mathematics it can be either based on probability not actuality.



which is the only way we ever prove anything. QM is different in the way the mathematical model relates to the physical system (in that we don't know how it does), but we cannot even explain the basic double-slit experiment if we assume that there is a particle going anywhere. First, because neither particles nor waves can interfere with themselves, and second because particles will never show an interference effect. Yet that's what happens.
I don't' see why a particle can't have a superposition and the superposition not actually be the photon. Your going by wavefunctions but it hasn't been proven that the particle is in both wavefunctions when it is split. The simplest answer being the most likely is that the physical aspect is not in two places but rather a projection of the physical aspect ie. superposition.
It isn't just the math. If you watch that cartoony clip you can see the "particles" going through the slits like we'd expect. Electrons (or photons etc.) no not do this. If they had a definite position, then they'd have a definite trajectory, and we'd have no interference pattern. It's the observations, not the math, that force us to abandon the idea of particles.
Again there are experiments that show the particle aspect so we can't just abandon it. That's like saying QM is all there is so lets abandon Newtonian physics, yet Newtonian is still very useful in the real world.

The delayed-choice just makes this even more confusing, because it indicates (as the authors state in the quotes above), either the particles aren't anywhere until we look, or are in multiple places.





First, this "collapse" is just a way of saying the system we described as being spread out over space has isn't any more. Second, watch the cartoon video again and compare how particles go through two slits with the interference pattern of two slits. Now let's imagine the impossible: a photon has gone through one slit and is about to show up in one of the spots that can only be explained via interference. Having assumed this, then as soon as it goes through that slit towards that spot we should be able to detect it taking the path to that spot. In fact, if we remove the detection screen right before it hits that spot, it should be right there. It won't be. Even though the photon has already travelled through the double-slit screen, and would (if we left the screen in place), hit a particular spot, if we remove the screen right before it lands, it will be somewhere totally different and (if we imagine that the photon is where the screen was a moment ago) it will be in a spot that we will never detect ever with the screen there.




In my previous post I included links to actual experiments. This is a quote from the conclusion of one: "In Wheeler’s words, since no signal traveling at a velocity less than that of light can connect these two events, 'we have a strange inversion of the normal order of time. We, now, by moving the mirror in or out have an unavoidable effect on what we have a right to say about the already past history of that photon'"

The point of the delayed-choice experiment isn't that the photon ends up at a weird location. It's that the only way it can be explained is by positing retrocausation: we have changed how the photon travelled from the double-slit screen after it has already gone through. We are changing its past.

I've watched some youtube that based on that cartoon they said that the photon was sending information back through time, the future choice of an experiment influencing the photon in real time. I gotta say I facepalmed inside when I heard that, and thats what made me grab that book again cause I had to see where that was coming from.

It should be clear to both of us that the experiment setup is influencing the photon. It "knows" because we changed something to let it know. Mind you we know that photons go the speed of light so to even try such an experiment is almost impossible. Even the way scientists have been able to pull it off I am pretty convinced that the photon is physically being influenced by the experiment which in turn gives the results we should expect, that the photon "knows", but time dilation I'm not so sure. Of course again photons going the speed of light, time dilation certainly isn't out of the question but thats basic relativity.
 

LegionOnomaMoi

Veteran Member
Premium Member
The book talks about how they have a school where they teach this stuff to non-scientists.

Huh. I don't remember that part, but I could sure use some tips from them.



Yeah I remember reading that and that caused it to click in my head. The test question emphasises, as I have, that it isn't saying it will "be" there but that you might "find" it there.

I figured that I didn't need to write "italics in original" because you had the book, but perhaps I should have pointed out more clearly why the italicized words were italicized. It's isn't that you "might 'find' it there", but that you caused it to be there by looking, and had you not looked, it wouldn't be there.


It is tricky but essentially the collapsing of the wavefunction causes the location to be specific.
It's important to be very clear what the wave function is. Although there are variations, whenever you hear or read "the wavefunction" or "the wave function", it refers to the physical system (electron, molecule, photon, etc.) in the experiment. For example, if we set up the double-slit experiment with an electron gun, either there are no electrons (or we have no idea what these really are), or the wave function is the electron(s).

This is what makes quantum physics radical. In classical physics, if I talk about "a system" like firing a .50 caliber rifle into a pool of water (I saw this on one of the few MythBusters episodes I've seen), everything in my mathematical model, from the distance between the muzzle and the water to the grain of the cartridge would have a direct and measurable correspondence with a physical "thing" I could see.

In quantum mechanics, the mathematical model IS the physical system. No photons, electrons, quarks, leptons, etc., exist apart as physical systems or anything physical at all without the mathematical model. The wavefunction isn't just a description of e.g., and electron in an experiment- it IS the electron.


I have read else where that they can do weak measurement by measuring the influenced area after the photon has passed to determine its trajectory after the fact.

I think you're confusing the delayed-choice experiment with the above. It's not that we can measure things after the fact to determine trajectories, but that measurements after the fact can create trajectories in the past that didn't exist.

Yes I remember this in the book as well. Which is where it clicked with me that QM treats the wave function literally as the particle. This becomes a problem when the double slit creates two wave functions and a need to call both the literal particle. The book shows the experiments that the photon is both particle and wave. You can do a specific experiment to prove either.

The double-slit doesn't "create" two wave functions. In order to explain the results, we combine two wave-functions to describe a single "particle". In other words, it's not just that a particle is wave-like, it's that it is more than one wave at the same time.

This leads to the need to say that the photon predicted what the experimenter would do which is ludicrous.

Yet we've done it.


In mathematics it can be either based on probability not actuality.
There is no actuality without the mathematics. The mathematics "is" the actuality, which is why QM is both incredibly successful and yet the interpretation of it is so contentious. QM treats the mathematical descriptions as identical to "actuality".



I don't' see why a particle can't have a superposition and the superposition not actually be the photon.

It can. But that's not a particle nor is it a wave. A superposition state is a state in which the photon exists in multiple, even infinite places at the same time.


Your going by wavefunctions but it hasn't been proven that the particle is in both wavefunctions when it is split.

There is no "split" and there is no particle. The photon, electron, or whatever quantum "particle" you wish to speak of exists only as a wavefunction until it is observed/measured.


The simplest answer being the most likely is that the physical aspect is not in two places but rather a projection of the physical aspect ie. superposition.

Superposition is being in multiple places. Otherwise we'd just call it the position.

Again there are experiments that show the particle aspect so we can't just abandon it.

We have to. There's no such thing as "particle aspects". Classical physics had particles. They didn't have things "like" particles. If you were a scientist working on how the human biological system functioned, would you call a statue "human-like"? Is it of any value to biologists, psychologist, doctors, etc., to call statues "human-like"?


That's like saying QM is all there is so lets abandon Newtonian physics, yet Newtonian is still very useful in the real world.

That's true. It's also true that from mathematics to science, most of education is a bunch of distortions. I cannot tell you how many times I've had some college student bring me a textbook for help on a problem or assignment and had to basically lie in order to have the student provide the answer. Classical physics is incredibly useful for a great many things. So is the integration (integral calculus) that physicists needed and which is described in every first course in calculus I know of. And then, when the student has studied abstract algrebras, topology, measure theory, etc., calculus turns into analysis and the integral the student was taught is thrown out, replaced with the Lebesgue integral.

Just because something is useful doesn't mean we should be afraid to admit its wrong.



It should be clear to both of us that the experiment setup is influencing the photon. It "knows" because we changed something to let it know.

Here's the problem. Let's say we assume that it "knows" because we changed something. So when the photon is about to be in location X, we change something an we find it in location Y. The problem is that in order for it to end up in location why, it would have had to travel down a specific trajectory (or magically jumped from one place to another). Either way, by changing something we've influenced the photon in a way that makes it impossible to explain if we assume it had a definite trajectory and position ever.
 

zaybu

Active Member
I've been reading this book named Quantum Enigma *gasps, see I blame you guys for making read lol*. It gives a nice history of the drama between the scientists as they developed the experiments and maths. I've learned a great deal from it and have been able to see a bit more of the problem. There is one things that I noticed that seems to be an issue. QM likes to describe the whole wave function as the particle, photon or electron. The peculiar thing is that when this wave function goes through the the two slits the maths say it is two wave functions and QM likes to see that as two "particles" but this is just abstract for the maths because in reality that photon packet (whatever its supposed to be) only goes through one slit even though its wave function goes through two.

This settles the idea in my head that there is a path traveled despite the maths that help qm make its probability predictions. The delayed choice is just another version of making the particle go a certain route because the detection is collapsing the wave function. Nothing in the experiments can prove the photon packet was in two places except the math. Observation puts the photon in one place which is wherever it happened to be observed thus causing a collapse. What QM can't really say is whether the superposition of the photon is actually the real photon or not. You can't tell until you open the box which is the randomness aspect of QM.

/rant :thud:

It's what I've been saying throughout this thread. You need to forget of trying to pidgeonhole these objects as they sometimes behave like waves, and at other times like particles. The wavefunction in QM is just a mathematical tool that allows us to calculate probabilities of certain outcomes due to the intrinsic randomness of nature at subatomic scale. Trying to see that wavefunction as "real" leads to nonsensical conclusions.
 

idav

Being
Premium Member
Huh. I don't remember that part, but I could sure use some tips from them.





I figured that I didn't need to write "italics in original" because you had the book, but perhaps I should have pointed out more clearly why the italicized words were italicized. It's isn't that you "might 'find' it there", but that you caused it to be there by looking, and had you not looked, it wouldn't be there.



It's important to be very clear what the wave function is. Although there are variations, whenever you hear or read "the wavefunction" or "the wave function", it refers to the physical system (electron, molecule, photon, etc.) in the experiment. For example, if we set up the double-slit experiment with an electron gun, either there are no electrons (or we have no idea what these really are), or the wave function is the electron(s).

This is what makes quantum physics radical. In classical physics, if I talk about "a system" like firing a .50 caliber rifle into a pool of water (I saw this on one of the few MythBusters episodes I've seen), everything in my mathematical model, from the distance between the muzzle and the water to the grain of the cartridge would have a direct and measurable correspondence with a physical "thing" I could see.

In quantum mechanics, the mathematical model IS the physical system. No photons, electrons, quarks, leptons, etc., exist apart as physical systems or anything physical at all without the mathematical model. The wavefunction isn't just a description of e.g., and electron in an experiment- it IS the electron.




I think you're confusing the delayed-choice experiment with the above. It's not that we can measure things after the fact to determine trajectories, but that measurements after the fact can create trajectories in the past that didn't exist.



The double-slit doesn't "create" two wave functions. In order to explain the results, we combine two wave-functions to describe a single "particle". In other words, it's not just that a particle is wave-like, it's that it is more than one wave at the same time.



Yet we've done it.



There is no actuality without the mathematics. The mathematics "is" the actuality, which is why QM is both incredibly successful and yet the interpretation of it is so contentious. QM treats the mathematical descriptions as identical to "actuality".





It can. But that's not a particle nor is it a wave. A superposition state is a state in which the photon exists in multiple, even infinite places at the same time.




There is no "split" and there is no particle. The photon, electron, or whatever quantum "particle" you wish to speak of exists only as a wavefunction until it is observed/measured.




Superposition is being in multiple places. Otherwise we'd just call it the position.



We have to. There's no such thing as "particle aspects". Classical physics had particles. They didn't have things "like" particles. If you were a scientist working on how the human biological system functioned, would you call a statue "human-like"? Is it of any value to biologists, psychologist, doctors, etc., to call statues "human-like"?




That's true. It's also true that from mathematics to science, most of education is a bunch of distortions. I cannot tell you how many times I've had some college student bring me a textbook for help on a problem or assignment and had to basically lie in order to have the student provide the answer. Classical physics is incredibly useful for a great many things. So is the integration (integral calculus) that physicists needed and which is described in every first course in calculus I know of. And then, when the student has studied abstract algrebras, topology, measure theory, etc., calculus turns into analysis and the integral the student was taught is thrown out, replaced with the Lebesgue integral.

Just because something is useful doesn't mean we should be afraid to admit its wrong.





Here's the problem. Let's say we assume that it "knows" because we changed something. So when the photon is about to be in location X, we change something an we find it in location Y. The problem is that in order for it to end up in location why, it would have had to travel down a specific trajectory (or magically jumped from one place to another). Either way, by changing something we've influenced the photon in a way that makes it impossible to explain if we assume it had a definite trajectory and position ever.
The influence is shown on the double slit experiment when they put the defector to observe the slits directly and it causes the photon to go through them randomly at 50/50. So if the wavefunction were some spread out thing then why does the influence of the detector manage to capture 100% of two slit? This is the same thing happening when you move the cameras. We are influencing the the path of the supposed spread out thing because it collapsed. It would collapse randomly when there are two slits because the photon will always come across the detector when I this in range. How it does it is probably through quantum teleporting, the other particle wasn't the actual particle.
If it isnt really a particle it makes more sense because then all that has to be transported is essentially a frequency.
 

LegionOnomaMoi

Veteran Member
Premium Member
The influence is shown on the double slit experiment when they put the defector to observe the slits directly and it causes the photon to go through them randomly at 50/50.

It doesn't. It causes the photon to go through both slits. Or neither. It all depends on how you wish to interpret the relationship between the mathematical description of the system (the only description we have) and the experimental outcomes. However, what we cannot say is that it travels through one of the slits.

So if the wavefunction were some spread out thing then why does the influence of the detector manage to capture 100% of two slit?

Because I think you are mistaking something rather important: the additive property of wave functions. Basically, we explain the results by treating the electron as two wave functions. That's what gets us the "100%". Alternatively, we treat the electron as "spread out" in order to get the "100%".


This is the same thing happening when you move the cameras. We are influencing the the path of the supposed spread out thing because it collapsed.

The term "collapse" means that the "spread out thing" ceases to be spread out. You can't "collapse" a wave function unless the system it describes is spread out.


If it isnt really a particle it makes more sense because then all that has to be transported is essentially a frequency.
A frequency is not a thing. You can't transport it. It is a description of how many instances of something occur in a given time interval. For waves, this is described in terms of how many cycles or periods (or in even simpler terms how many "peaks" or how many "troughs") occur in a given interval of time (usually a second).
 

idav

Being
Premium Member
If the detection is spread out it detects anywhere ie. the screen.. When it was the telescope it only detected there not giving opportunity for it to detect as a spread out. The boxes will detect 100% as well as the screen would, and yes they are both collapsing but only at points we influence the wave function. How is it that we can collapse the wave anywhere 100% of the time. Whether it is spread out like a screen or boxes or telescope? It does appear that the photon can be everywhere almost instantaneously but a photon is pretty fast already. Keep note that it isn't in two places at once as they've shown the particle only goes through one slit at a time despite the randomness capability.
 

LegionOnomaMoi

Veteran Member
Premium Member
If the detection is spread out it detects anywhere ie. the screen.
The detection isn't spread out. That's the key point. The interference pattern that shows up as electrons hit the detection screen one at a time requires a description in which the electron is spread out. But it is not ever detected this way. In other words, unless we describe the individual spots on the screen as spread out, we can't account for where they show up. We are forced to treat (i..e, describe in our models) what we detect as being spread out even though we never detect it as actually spread out.
 

LegionOnomaMoi

Veteran Member
Premium Member
The screen counts as detection.
Absolutely. It IS the detection. But we don't detect anything spread out on the screen. You've seen it on the clips, those spots that show up one at a time. The problem is that there's no way we can account for them showing up where we do unless we understand/model/treat the "blips" detected as spread out right until they hit the screen.
 

idav

Being
Premium Member
Absolutely. It IS the detection. But we don't detect anything spread out on the screen. You've seen it on the clips, those spots that show up one at a time. The problem is that there's no way we can account for them showing up where we do unless we understand/model/treat the "blips" detected as spread out right until they hit the screen.

Yes and if that were not puzzling enough the detection detects whether the "screen" were the back of two small boxes or a huge screen to catch a larger spectrum of the function. It doesn't make sense that the photon would know whether we pick the boxes are a large screen which means the physical setup of the experiment causes them to be in a particular location even though it is supposed to be spread out. In other words, if the particle was going down a particular path to begin with then it should miss the boxes sometimes but instead the boxes interfere with the function and collapse it.
 

LegionOnomaMoi

Veteran Member
Premium Member
Yes and if that were not puzzling enough the detection detects whether the "screen" were the back of two small boxes or a huge screen to catch a larger spectrum of the function.

It's important to separate the "boxes" descriptions from the "screen" descriptions. For one thing, the path or trajectory that applies with a detection screen can't be applied to the "boxes".

However, whether one refers to simplified versions of Wheeler's thought experiment of to the dozens and dozens of actual published experiments, the result is the same. There is no definite path or trajectory and no particle. There is only an approximation of a particle and a description of some physical system that is decent for most "large" systems but becomes radically inaccurate for quantum systems.
 

idav

Being
Premium Member
It's important to separate the "boxes" descriptions from the "screen" descriptions. For one thing, the path or trajectory that applies with a detection screen can't be applied to the "boxes".

However, whether one refers to simplified versions of Wheeler's thought experiment of to the dozens and dozens of actual published experiments, the result is the same. There is no definite path or trajectory and no particle. There is only an approximation of a particle and a description of some physical system that is decent for most "large" systems but becomes radically inaccurate for quantum systems.

The weird part is when putting the detector at the double slit, similar to the box detectors, the photon always manages to take the path where the detectors are which means they are interfering with the experiment. Without the detectors at the slits the photons would have gone on in there spread out way hitting the screen spread out. Then if you use telescopes instead of a screen the photons find that specific path ignoring the random places it should have landed.

I'm talking about this because of the delayed choice experiment you mentioned doing time loops and what not. It isn't a delayed choice at all, it did the exact same thing as observing at the point of the slits. The best way to pose the question is how does the photon always find the two slits one hundred percent of the time supposing it started as a wavefunction when the photon was fired. That answer will tell you why it does that for the delayed experiment because the photons find the delayed choice 100% of the time.

This is why we can't say either way if the photon takes a specific path because the experiments are clearly interfering with the results.
 

PolyHedral

Superabacus Mystic
I'm not sure (again) I understand you (ill-fitting models?), but typically there is a lot less "interpretation" and a lot more "description".
Which implies an interpretation. More on that in a sec.

But I digress (because I have become so hateful of most social and behavioral research studies and this was too much to handle). Back to actual scientists.
3qm6ym_zpsb4963cff.jpg


QM has a great mathematical model. [...]
Of course, it's important to keep in mind that quantum physics is actually completely made-up. In reality, the two "clouds" Lord Kelvin mentioned were solved and the advice Max Planck got about not going into physics (because everything was pretty much wrapped up and solved) was true. But physicists still wanted jobs, so they decided to create QM.
Oh shush. I'm not so moronic as to doubt the maths. :p I'm doubting the semantics people are assigning to the maths.

As you pointed out to idav, there's nothing "there" apart from the wavefunction. There's no particle, or wave-in-something. There's only a wibbly-wobbly quantum-y thing, so when you say that such-and-such experiment proves something ridiculous, like a particle being in two places at once, or photons knowing whether or not we've moved the screen before it happened, I don't believe you.

I don't fail to believe you because I think the experimental data is wrong - I fail to believe you because I think you misinterpreted what the data and/or the model that explains the data is telling you.

For example, the idea of a molecule being in two different places at once is completely ludicrous. The idea of a wibbly-wobbly complex wavefunction being distributed in space and concentrated in two different volumes? That's fine, that's what wavefunctions do! If you were explaining the result with a lie-to-students, you might say the first thing, but that doesn't make it right. :p
 

LegionOnomaMoi

Veteran Member
Premium Member
Oh shush. I'm not so moronic as to doubt the maths. :p I'm doubting the semantics people are assigning to the maths.
Those two statements weren't meant to be connected. That is, the mathematical model part was serious, but I was in a good mood (relative state good mood) at the time and included the other studies mostly for fun. The bit about QM being made up is something I've said frequently as a joke, and had nothing to do with the mathematical models.

As you pointed out to idav, there's nothing "there" apart from the wavefunction.

There's nothing there in the experimental sense. That is, we are describing a system mathematically in order to relate physical systems we set-up to measurements we perform, but we do not have the correspondence between the models and the systems that is typical in every other scientific field.

There's no particle, or wave-in-something. There's only a wibbly-wobbly quantum-y thing, so when you say that such-and-such experiment proves something ridiculous, like a particle being in two places at once, or photons knowing whether or not we've moved the screen before it happened, I don't believe you.

Keep in mind, then, that the way I describe things to you might differ from the way I describe things to others. If I were addressing Mr. Sprinkles, for example, I would tend to be very precise and technical. You are not new to physics, and neither you nor me are physicists, but we both have some experience reading the literature (I think it's safe to say I have more, but only because I have access and weird hobbies, not because I am any smarter than anybody or work in a field more related to QM than you). I'm trying to work on my teaching methods, which involve simplifying with minimal loss of accuracy, but there will be some. So it would be better for our exchanges if you did not use my explanations to others as a guide.

I don't fail to believe you because I think the experimental data is wrong - I fail to believe you because I think you misinterpreted what the data and/or the model that explains the data is telling you.

Fair enough, but this is not:

For example, the idea of a molecule being in two different places at once is completely ludicrous.
This was Einstein's reaction to what is now just universally accepted. If you would like to explain the results differently and why the researchers did not adequately account for whatever it is that made their conclusion inaccurate, feel free.


The idea of a wibbly-wobbly complex wavefunction being distributed in space and concentrated in two different volumes?

Volumes? You do know that after we leave 3D determinants don't give us volume anymore, right? Or are you referring to something else?

If you were explaining the result with a lie-to-students, you might say the first thing, but that doesn't make it right. :p
Couldn't agree more. But I don't think I've lied about anything. Simplified? yes. But also there is the issue of a third party (as it were): a book. So I had to incorporate the authors' descriptions as well.
 

PolyHedral

Superabacus Mystic
There's nothing there in the experimental sense. That is, we are describing a system mathematically in order to relate physical systems we set-up to measurements we perform, but we do not have the correspondence between the models and the systems that is typical in every other scientific field.
I still don't know what correspondance you're looking for. In the era of Rutherford messing around with gold foil, we said that the nucleus was a collection of charged spheres, even though we hadn't actually seen them and later on saw there were no spheres to be found.

Or was there some "reality" missing from the wavefunctions that the spheres had? :p

Keep in mind, then, that the way I describe things to you might differ from the way I describe things to others. If I were addressing Mr. Sprinkles, for example, I would tend to be very precise and technical. You are not new to physics, and neither you nor me are physicists, but we both have some experience reading the literature (I think it's safe to say I have more, but only because I have access and weird hobbies, not because I am any smarter than anybody or work in a field more related to QM than you). I'm trying to work on my teaching methods, which involve simplifying with minimal loss of accuracy, but there will be some. So it would be better for our exchanges if you did not use my explanations to others as a guide.
I'm not talking about only this thread, although I am fairly sure you have specifically said that exact thing to me specifically at least once.

Volumes? You do know that after we leave 3D determinants don't give us volume anymore, right? Or are you referring to something else?
I actually meant to mean the probability distribution after you apply the right operators and Born rule everything. That's 3D. (or maybe 4, but who's asking?)

Also, I'm now kinda intrigued about if it's possible to "visualize" the same WF in different dimensional spaces, although I suspect that this'll cause a type error. :D

This was Einstein's reaction to what is now just universally accepted. If you would like to explain the results differently and why the researchers did not adequately account for whatever it is that made their conclusion inaccurate, feel free.
The explanation is: thinking in terms of particles - and spraying paint everywhere as a result - is wrong. The objects being described by QM are not particles (or waves) and do not obey the rules of what particles do, so thinking in terms of molecules "being in two places at once" is a type error - akin to thinking of a point-like cow, or a pressurized shade of blue, or a curious green idea.

There's nothing mysterious about wavefunctions being spread out, or doing bonkers things like what we see in delayed choice experiments. The mistake is to interpret the wavefunction as the probability of finding a particle there - there is no particle, only an entanglement. :D (Also, the universe isn't actually built out of anything, but is merely a linear algebra calculator...)

Couldn't agree more. But I don't think I've lied about anything. Simplified? yes.
Sorry, I assumed you would be aware of the expression lies-to-children.
 

LegionOnomaMoi

Veteran Member
Premium Member
I still don't know what correspondance you're looking for. In the era of Rutherford messing around with gold foil, we said that the nucleus was a collection of charged spheres, even though we hadn't actually seen them and later on saw there were no spheres to be found.

Can you describe for me what the no-cloning theorem is?

The models we use are actually models of the experiment outcomes before the experiment is performed. We describe the physical system in such a way that it's specifications are determined by outcomes which have not yet happened and are determined through statistical means and are only related to anything we do via a measurement which requires another mathematical function completely separate from the one we called the system.

Perhaps there's a better way of getting at this. Why do we us amplitudes instead of calculating probabilities directly in QM?




Or was there some "reality" missing from the wavefunctions that the spheres had? :p

Yes, of course. All models are wrong. That's why we have statistical mechanics. We know that we're wrong but things get too complicated. The difference is that we called it "statistical mechanics" because we were using probability theory and statistics to simplify some system yet say something meaningful. Here, we're doing much the same, only we are calling the probability function the system rather than describing the system in terms of probabilities.



You know that observation in QM effects the system in non-trivial ways. In fact, you believe that it causes a branching universe. If we want to describe how a quantum system evolves over time, but we know that any observation of the system will disturb it in some non-trivial way (whether "collapsing" or creating "branching histories" or "branching universe" or whatever), how do we specify the initial state of the system such that we can describe how it evolves?



I'm not talking about only this thread, although I am fairly sure you have specifically said that exact thing to me specifically at least once.

If I did, I meant it to be conditional. That is, given the way we are describing the system, the specifications of the system are conditioned by theory not measurement/observation, and the measurements/observations are related to the system we described via a mathematical function developed independently and in advance. This is because when we set-up the experiment, we are describing the state of something that we cannot obtain without altering it in ways that would make the experiment impossible. It's not that no physical system exists, but we have described something that doesn't.

To see that this is obvious in at least one sense, think of the fact that the state vector is said to contain all possible information about the system.
1) How can that be true if the uncertainty principle is true?
2) If we have completely described the system, and we observe it at some point, why do we need Hermitian operators to tell us what we observe?


I actually meant to mean the probability distribution after you apply the right operators and Born rule everything. That's 3D. (or maybe 4, but who's asking?)
The Born rule-
"The probability that a measurement on an observable A of a system in a state described by a state vector ψ = Σi ciφi will yield an eigenvalue αn is |Cn|^2, where Aφn = αn φn, with A is the operator corresponding to observable A, with ψ and φi normalised: (ψ,ψ) = 1 = (φi, φi)."


Now I'm asking: The state vector of some pure system is a complete description of the system as an element in Hilbert space. How do we determine what the variables that are characteristic of the system are? Put simply: we have a vector that isn't generalized with n this or a1, a2, etc., but with actual values. How do we obtain these values?


Also, I'm now kinda intrigued about if it's possible to "visualize" the same WF in different dimensional spaces

In honor of Socrates, let's speculate about the space itself (using language that implies "we/us" and questions as if we both didn't know where this was going, when really I do and it's so annoying that they finally just killed Socrates for doing it). Regardless of dimension, we describe the system in terms or a ray or a vector in a Hilbert space. At then end of an experiment, is the system still in Hilbert space? Our we in Hilbert space? If the answer to both is "yes", then why do we ever talk about some system in terms of anything other than Hilbert space (more specifically, Euclidean or Minkowski space)? If the answer to the first is "yes", then what does the projection postulate entail in terms of the space in which the system is and the values obtained by measurement?


The explanation is: thinking in terms of particles - and spraying paint everywhere as a result - is wrong. The objects being described by QM are not particles (or waves) and do not obey the rules of what particles do, so thinking in terms of molecules "being in two places at once" is a type error - akin to thinking of a point-like cow, or a pressurized shade of blue, or a curious green idea.

That's the standard model you've said we need to get rid of: QM is irreducibly statistical and we don't ask questions like what exists before we measure a quantum system and we don't try to interpret the measurement (either in terms of splitting branches or as a spread out physical system actually collapsing to a point-like state or any other interpretation). The issue is that this interpretation (or perhaps non-interpretation is a better description) was developed when physics was still about idealized isolated systems. Schroedinger's cat was the first serious challenge to this logic as it used quantum formalism, that "it's just math" approach, and proved that a cat can be alive and dead at the same time. You, it seems, wish to keep the standard model but apply post hoc a description for which there is no reason and without explaining why we used the standard model (preparing a system through a transcription process in which the system is described in terms of statistical theory, the measurement apparatus, and the measurement process, and then observing this "system" by another step in the measurement process coupled with another mathematical function). Let's assume some possible world where we are both renowned physicists with the necessary equipment to prepare a quantum system for an experimental procedure. We use the same formalisms and the same design. So why isn't it like rolling dice? That is, even though we're using probabilities, we aren't generalizing them in the way we do for rolling dice such that given an idealized system (dice or quantum), one prepared and transcribed in the same way, we can't just say the probability of getting snake eyes is constant (as it is in classical probability and statistical mechanics)?



There's nothing mysterious about wavefunctions being spread out, or doing bonkers things like what we see in delayed choice experiments. The mistake is to interpret the wavefunction as the probability of finding a particle there - there is no particle, only an entanglement

There is everything mysterious about wavefunctions being spread out, because I don't typically call the probability of getting heads or tail flipping a fair coin as being spread out. The wave function is a probability function, whether you wish to think of it in terms of finding particles or not. The relative state interpretations all have the same or a similar problem, from Everett to whomever it was who reincarnated his work (Deutsch? DeWitt?) now with a new an improved title (many-worlds interpretation) to the polymodal omniontologistical interpretation. Probability functions describe the probability of something. I get heads or tails. In QM, we describe something like the double-slit experiment in terms of the following probabilities: getting one result corresponding (in some way) to detection and to one of the slits, getting a result corresponding (in some way) to the other, and getting a result corresponding to both. But we never get both, and thus if we assume that both occurred we are no longer dealing with probabilities (because all outcomes occur), but we are using them regardless. We are applying probabilistic reasoning without a basis for our probabilistic outcome.


the universe isn't actually built out of anything, but is merely a linear algebra calculator

As long as it doesn't use Dirac's notation.

Sorry, I assumed you would be aware of the expression lies-to-children.

I am, although my interpretation of it differs from Wikipedia's which I find too often reflects the defense of those who distort and claim it is simplification. The way math is taught and the way psych students learn about neurons are perfect examples.
EDIT: I don't think I've heard this term and was confusing it with 'the noble lie' which, thankfully, is basically the same.
 
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