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Photon double-slit experiment

000ike
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7/18/2013 2:25:17 PM
Posted: 3 years ago
Alright, so they fire a beam of light through two slits, it diffracts, the two separate waves constructively and destructively interfere, and so the there's something like a serrated pattern of intense light and no light at all on the screen. That's easy enough to digest. What's making my head spin is how they receive the same results when they fire individual photons or electrons. The explanation is that the electromagnetic wave represents a probability distribution, and where the wave is constructively amplified, the particle is most likely to land, the reverse for the destructively diminished portions of the wave. But the interference is dependent on the interaction of two separate waves. If you fire a photon/electron individually, there's no other wave-like particle to offer the interference (as there would be , so how does the same pattern emerge??

Am I right in thinking that the single photon is a wave that passes through both slits and then diffracts and interferes with itself (whatever that means)?
"A stupid despot may constrain his slaves with iron chains; but a true politician binds them even more strongly with the chain of their own ideas" - Michel Foucault
Subutai
Posts: 3,235
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7/18/2013 2:30:52 PM
Posted: 3 years ago
I'm not sure how much this will help you (you might have to read it a few times, as I have), but here is a good explanation:

Some time before the discovery of quantum mechanics people realized that the connection between light waves and photons must be of a statistical character. What they did not clearly realize, however, was that the wave function gives information about the probability of one photon being in a particular place and not the probable number of photons in that place. The importance of the distinction can be made clear in the following way. Suppose we have a beam of light consisting of a large number of photons split up into two components of equal intensity. On the assumption that the beam is connected with the probable number of photons in it, we should have half the total number going into each component. If the two components are now made to interfere, we should require a photon in one component to be able to interfere with one in the other. Sometimes these two photons would have to annihilate one another and other times they would have to produce four photons. This would contradict the conservation of energy. The new theory, which connects the wave function with probabilities for one photon gets over the difficulty by making each photon go partly into each of the two components. Each photon then interferes only with itself. Interference between two different photons never occurs.(Dirac)

Sources

Paul Dirac, The Principles of Quantum Mechanics, Fourth Edition, Chapter 1
I'm becoming less defined as days go by, fading away, and well you might say, I'm losing focus, kinda drifting into the abstract in terms of how I see myself.
000ike
Posts: 11,196
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7/18/2013 2:41:16 PM
Posted: 3 years ago
At 7/18/2013 2:30:52 PM, Subutai wrote:
I'm not sure how much this will help you (you might have to read it a few times, as I have), but here is a good explanation:

Some time before the discovery of quantum mechanics people realized that the connection between light waves and photons must be of a statistical character. What they did not clearly realize, however, was that the wave function gives information about the probability of one photon being in a particular place and not the probable number of photons in that place. The importance of the distinction can be made clear in the following way. Suppose we have a beam of light consisting of a large number of photons split up into two components of equal intensity. On the assumption that the beam is connected with the probable number of photons in it, we should have half the total number going into each component. If the two components are now made to interfere, we should require a photon in one component to be able to interfere with one in the other. Sometimes these two photons would have to annihilate one another and other times they would have to produce four photons. This would contradict the conservation of energy. The new theory, which connects the wave function with probabilities for one photon gets over the difficulty by making each photon go partly into each of the two components. Each photon then interferes only with itself. Interference between two different photons never occurs.(Dirac)

Sources

Paul Dirac, The Principles of Quantum Mechanics, Fourth Edition, Chapter 1

thank you. That really helps. But I'm just curious: Is it also a valid objection (to the concept of 2 different photons interfering) that if interference were dependent on the influence of another photon, then as individual photons were fired through the double slit, they would not show interference lines and instead distribute randomly? This is what confused me in the first place.
"A stupid despot may constrain his slaves with iron chains; but a true politician binds them even more strongly with the chain of their own ideas" - Michel Foucault
slo1
Posts: 4,354
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7/18/2013 4:44:01 PM
Posted: 3 years ago
At 7/18/2013 2:41:16 PM, 000ike wrote:
At 7/18/2013 2:30:52 PM, Subutai wrote:
I'm not sure how much this will help you (you might have to read it a few times, as I have), but here is a good explanation:

Some time before the discovery of quantum mechanics people realized that the connection between light waves and photons must be of a statistical character. What they did not clearly realize, however, was that the wave function gives information about the probability of one photon being in a particular place and not the probable number of photons in that place. The importance of the distinction can be made clear in the following way. Suppose we have a beam of light consisting of a large number of photons split up into two components of equal intensity. On the assumption that the beam is connected with the probable number of photons in it, we should have half the total number going into each component. If the two components are now made to interfere, we should require a photon in one component to be able to interfere with one in the other. Sometimes these two photons would have to annihilate one another and other times they would have to produce four photons. This would contradict the conservation of energy. The new theory, which connects the wave function with probabilities for one photon gets over the difficulty by making each photon go partly into each of the two components. Each photon then interferes only with itself. Interference between two different photons never occurs.(Dirac)

Sources

Paul Dirac, The Principles of Quantum Mechanics, Fourth Edition, Chapter 1

thank you. That really helps. But I'm just curious: Is it also a valid objection (to the concept of 2 different photons interfering) that if interference were dependent on the influence of another photon, then as individual photons were fired through the double slit, they would not show interference lines and instead distribute randomly? This is what confused me in the first place.

A single photon, electron, atom, etc fired through double slits will create interference lines(the interference pattern is actually created by shooting photons, electrons or atoms one at a time. The results of all the single shots shows an interference pattern.)

Interestingly, if you place a detector in the slits so you can detect which slit the photon travels through, it does not create an interference pattern.

I think the reality of the situation is that nobody really knows what is going on and as a result why there are many different interpretations. We just know it happens.

This guy demonstrates it very well.
Subutai
Posts: 3,235
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7/18/2013 5:05:26 PM
Posted: 3 years ago
At 7/18/2013 4:44:01 PM, slo1 wrote:
At 7/18/2013 2:41:16 PM, 000ike wrote:
At 7/18/2013 2:30:52 PM, Subutai wrote:
I'm not sure how much this will help you (you might have to read it a few times, as I have), but here is a good explanation:

Some time before the discovery of quantum mechanics people realized that the connection between light waves and photons must be of a statistical character. What they did not clearly realize, however, was that the wave function gives information about the probability of one photon being in a particular place and not the probable number of photons in that place. The importance of the distinction can be made clear in the following way. Suppose we have a beam of light consisting of a large number of photons split up into two components of equal intensity. On the assumption that the beam is connected with the probable number of photons in it, we should have half the total number going into each component. If the two components are now made to interfere, we should require a photon in one component to be able to interfere with one in the other. Sometimes these two photons would have to annihilate one another and other times they would have to produce four photons. This would contradict the conservation of energy. The new theory, which connects the wave function with probabilities for one photon gets over the difficulty by making each photon go partly into each of the two components. Each photon then interferes only with itself. Interference between two different photons never occurs.(Dirac)

Sources

Paul Dirac, The Principles of Quantum Mechanics, Fourth Edition, Chapter 1

thank you. That really helps. But I'm just curious: Is it also a valid objection (to the concept of 2 different photons interfering) that if interference were dependent on the influence of another photon, then as individual photons were fired through the double slit, they would not show interference lines and instead distribute randomly? This is what confused me in the first place.

A single photon, electron, atom, etc fired through double slits will create interference lines(the interference pattern is actually created by shooting photons, electrons or atoms one at a time. The results of all the single shots shows an interference pattern.)

Interestingly, if you place a detector in the slits so you can detect which slit the photon travels through, it does not create an interference pattern.

I think the reality of the situation is that nobody really knows what is going on and as a result why there are many different interpretations. We just know it happens.

This guy demonstrates it very well.


Definitely a very informative video, and should definitely help demystify your problem. I'm going to watch it myself sometime this week.
I'm becoming less defined as days go by, fading away, and well you might say, I'm losing focus, kinda drifting into the abstract in terms of how I see myself.
tBoonePickens
Posts: 3,266
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7/18/2013 5:09:21 PM
Posted: 3 years ago
At 7/18/2013 4:44:01 PM, slo1 wrote:
At 7/18/2013 2:41:16 PM, 000ike wrote:
At 7/18/2013 2:30:52 PM, Subutai wrote:
I'm not sure how much this will help you (you might have to read it a few times, as I have), but here is a good explanation:

Some time before the discovery of quantum mechanics people realized that the connection between light waves and photons must be of a statistical character. What they did not clearly realize, however, was that the wave function gives information about the probability of one photon being in a particular place and not the probable number of photons in that place. The importance of the distinction can be made clear in the following way. Suppose we have a beam of light consisting of a large number of photons split up into two components of equal intensity. On the assumption that the beam is connected with the probable number of photons in it, we should have half the total number going into each component. If the two components are now made to interfere, we should require a photon in one component to be able to interfere with one in the other. Sometimes these two photons would have to annihilate one another and other times they would have to produce four photons. This would contradict the conservation of energy. The new theory, which connects the wave function with probabilities for one photon gets over the difficulty by making each photon go partly into each of the two components. Each photon then interferes only with itself. Interference between two different photons never occurs.(Dirac)

Sources

Paul Dirac, The Principles of Quantum Mechanics, Fourth Edition, Chapter 1

thank you. That really helps. But I'm just curious: Is it also a valid objection (to the concept of 2 different photons interfering) that if interference were dependent on the influence of another photon, then as individual photons were fired through the double slit, they would not show interference lines and instead distribute randomly? This is what confused me in the first place.

A single photon, electron, atom, etc fired through double slits will create interference lines(the interference pattern is actually created by shooting photons, electrons or atoms one at a time. The results of all the single shots shows an interference pattern.)

Interestingly, if you place a detector in the slits so you can detect which slit the photon travels through, it does not create an interference pattern.

I think the reality of the situation is that nobody really knows what is going on and as a result why there are many different interpretations. We just know it happens.

This guy demonstrates it very well.

So the detector interferes with the experiment.
WOS
: At 10/3/2012 4:28:52 AM, Wallstreetatheist wrote:
: Without nothing existing, you couldn't have something.
slo1
Posts: 4,354
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7/19/2013 8:22:37 AM
Posted: 3 years ago
At 7/18/2013 5:09:21 PM, tBoonePickens wrote:
So the detector interferes with the experiment.

Yep, and that is one thing that makes things at a quantum level so mysterious.

Although I recall this article from months ago where these guys measured the polarization of a photon. They were able to do it "weakly" so the disruption of the measurement resulted in less than expected by Heisenberg's uncertainty principle.

"Scientists cast dobut on Heisenberg Uncertainty Principle"
http://www.sciencedaily.com...

Although I would have to imagine a photon going through a slit that is still able to pass through the slit and be recorded at a later time on the background has been "weakly" measured.

Even De Broglie Bohm theory requires the wavefunction collapsing and the photo having a type of internal structure that acts upon the information of the wavefunction collapsing. It is an very unsatisfying explanation.
tBoonePickens
Posts: 3,266
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7/19/2013 11:45:36 AM
Posted: 3 years ago
At 7/19/2013 8:22:37 AM, slo1 wrote:
At 7/18/2013 5:09:21 PM, tBoonePickens wrote:
So the detector interferes with the experiment.
Yep, and that is one thing that makes things at a quantum level so mysterious.
I guess, but all we are doing is measuring different aspects of the same thing.

Although I recall this article from months ago where these guys measured the polarization of a photon. They were able to do it "weakly" so the disruption of the measurement resulted in less than expected by Heisenberg's uncertainty principle.

"Scientists cast dobut on Heisenberg Uncertainty Principle"
http://www.sciencedaily.com...
So the measurement was less disruptive; kind of like the difference between completely covering a slit and partially covering it (like with a detector.)

Although I would have to imagine a photon going through a slit that is still able to pass through the slit and be recorded at a later time on the background has been "weakly" measured.
Not sure what you mean by this.

Even De Broglie Bohm theory requires the wavefunction collapsing and the photo having a type of internal structure that acts upon the information of the wavefunction collapsing. It is an very unsatisfying explanation.
I think Bohmian Mechanics explains it just fine.
WOS
: At 10/3/2012 4:28:52 AM, Wallstreetatheist wrote:
: Without nothing existing, you couldn't have something.
slo1
Posts: 4,354
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7/19/2013 5:55:52 PM
Posted: 3 years ago
At 7/19/2013 11:45:36 AM, tBoonePickens wrote:
At 7/19/2013 8:22:37 AM, slo1 wrote:
At 7/18/2013 5:09:21 PM, tBoonePickens wrote:
So the detector interferes with the experiment.
Yep, and that is one thing that makes things at a quantum level so mysterious.
I guess, but all we are doing is measuring different aspects of the same thing.

Although I recall this article from months ago where these guys measured the polarization of a photon. They were able to do it "weakly" so the disruption of the measurement resulted in less than expected by Heisenberg's uncertainty principle.

"Scientists cast dobut on Heisenberg Uncertainty Principle"
http://www.sciencedaily.com...
So the measurement was less disruptive; kind of like the difference between completely covering a slit and partially covering it (like with a detector.)

Although I would have to imagine a photon going through a slit that is still able to pass through the slit and be recorded at a later time on the background has been "weakly" measured.
Not sure what you mean by this.

Even De Broglie Bohm theory requires the wavefunction collapsing and the photo having a type of internal structure that acts upon the information of the wavefunction collapsing. It is an very unsatisfying explanation.
I think Bohmian Mechanics explains it just fine.

Bohmian Mechanics is just a deterministic non-local interpretation that replicates the same predictions of the non-deterministic interpretations.

Until you can uncover the hidden variables which make it deterministic, how can you portray it as complete and adequate explanation? It is a little cocksure, if you ask me.
FREEDO
Posts: 21,057
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7/20/2013 4:11:32 AM
Posted: 3 years ago
It becomes clearer when we realize that, in the sub-atomic world, there are neither any literal particles, nor waves. These are names we give them to help our minds build a picture. The quantum world confuses us when we have one particle in two places at once. All along, not realizing that we are the ones drawing the lines. I'm not surprised to know that I live in both California and America, because that's the way I know it's been drawn. In reality, there's only the rock I stand on.
GRAND POOBAH OF DDO

fnord
slo1
Posts: 4,354
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7/20/2013 7:13:04 AM
Posted: 3 years ago
At 7/20/2013 4:11:32 AM, FREEDO wrote:
It becomes clearer when we realize that, in the sub-atomic world, there are neither any literal particles, nor waves. These are names we give them to help our minds build a picture. The quantum world confuses us when we have one particle in two places at once. All along, not realizing that we are the ones drawing the lines. I'm not surprised to know that I live in both California and America, because that's the way I know it's been drawn. In reality, there's only the rock I stand on.

Another interesting factoid. The double slit experiment has been performed with molecules comprised of a 114 atoms. They still create the interference pattern...........whaaaaaaaaaaaaaaaaaat?

It could be that the rock you stand on it only there because you are there. There is an emerging branch that is focusing more on the relationship of matter versus trying to explain it as a particle or wave. Scientific America had a good article on it this month.
Rational_Thinker9119
Posts: 9,054
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7/21/2013 11:54:40 AM
Posted: 3 years ago
If there is one truth we can get from quantum mechanics, it is that materialism and realism are false. The implications of this are staggering...
Rational_Thinker9119
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7/21/2013 12:03:50 PM
Posted: 3 years ago
The double-slit experiment shows that local-realism is false, and if that wasn't enough, Bell's inequalities show that local realism is false[1] with almost no loopholes left for the determinist or realist. What about non-local reaslism? Leggett's inequalities being violated proves that non-local realism is false, and the before-before experiment[2]. Also, if that wasn't enough, this should really do it:

"No naive realistic picture is compatible with our results because whether a quantum could be seen as showing particle- or wave-like behavior would depend on a causally disconnected choice. It is therefore suggestive to abandon such pictures altogether."[3]

All one has to do is understand that reality isn't really "real", then double-slit experiments start to make a lot more sense.

[1] http://www.pnas.org...
[2] http://www.quantumphil.org...
[3] arxiv . org/abs/1206 . 6578
Sower4GS
Posts: 1,718
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7/21/2013 3:30:46 PM
Posted: 3 years ago
Air max is ticked, I believe He or She (duno really never met em) is a Jew. YHWH is convicting Him the Maschiach is here and He will have none of it. I will be back after a while. In the mean-time Seek truth in Scripture, YHWH may close this door the the seed He has planted through His servant Sower For the Good Sheppard can grow, I will be back before Ya'acob's Trouble (Tribulation) takes full hold to Reap the Harvest. Shalom.

Look the Father's name, your Creator and His Son are ONE.
YHWH means "Set apart" ok? Not from this Earth. He Created it and you and everything. Simple. Yet He is Awesome.

That is why people cannot comprehend him and demand proof First, well it does not work that way. Trust first, make a decision, then Blessings. Salvation and the whole Whammy follow.

See you all around, As the Governor of Cali said once "I'll be back" For Intellectuals you sure are a rowdy bunch. If YHWH was not convicting the socks off of you then you would all of actually found me quite funny and likable. But it is not about me, now is it. My name is Yohanan. It means John in English and YHWH is Gracious. Bye you guys....hahaha I had some good laughs.
Sower4GS
Posts: 1,718
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7/21/2013 3:31:21 PM
Posted: 3 years ago
At 7/18/2013 2:41:16 PM, 000ike wrote:
At 7/18/2013 2:30:52 PM, Subutai wrote:
I'm not sure how much this will help you (you might have to read it a few times, as I have), but here is a good explanation:

Some time before the discovery of quantum mechanics people realized that the connection between light waves and photons must be of a statistical character. What they did not clearly realize, however, was that the wave function gives information about the probability of one photon being in a particular place and not the probable number of photons in that place. The importance of the distinction can be made clear in the following way. Suppose we have a beam of light consisting of a large number of photons split up into two components of equal intensity. On the assumption that the beam is connected with the probable number of photons in it, we should have half the total number going into each component. If the two components are now made to interfere, we should require a photon in one component to be able to interfere with one in the other. Sometimes these two photons would have to annihilate one another and other times they would have to produce four photons. This would contradict the conservation of energy. The new theory, which connects the wave function with probabilities for one photon gets over the difficulty by making each photon go partly into each of the two components. Each photon then interferes only with itself. Interference between two different photons never occurs.(Dirac)

Sources

Paul Dirac, The Principles of Quantum Mechanics, Fourth Edition, Chapter 1

thank you. That really helps. But I'm just curious: Is it also a valid objection (to the concept of 2 different photons interfering) that if interference were dependent on the influence of another photon, then as individual photons were fired through the double slit, they would not show interference lines and instead distribute randomly? This is what confused me in the first place.

Air max is ticked, I believe He or She (duno really never met em) is a Jew. YHWH is convicting Him the Maschiach is here and He will have none of it. I will be back after a while. In the mean-time Seek truth in Scripture, YHWH may close this door the the seed He has planted through His servant Sower For the Good Sheppard can grow, I will be back before Ya'acob's Trouble (Tribulation) takes full hold to Reap the Harvest. Shalom.

Look the Father's name, your Creator and His Son are ONE.
YHWH means "Set apart" ok? Not from this Earth. He Created it and you and everything. Simple. Yet He is Awesome.

That is why people cannot comprehend him and demand proof First, well it does not work that way. Trust first, make a decision, then Blessings. Salvation and the whole Whammy follow.

See you all around, As the Governor of Cali said once "I'll be back" For Intellectuals you sure are a rowdy bunch. If YHWH was not convicting the socks off of you then you would all of actually found me quite funny and likable. But it is not about me, now is it. My name is Yohanan. It means John in English and YHWH is Gracious. Bye you guys....hahaha I had some good laughs.
Sidewalker
Posts: 3,713
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7/21/2013 5:05:42 PM
Posted: 3 years ago
At 7/21/2013 3:31:21 PM, Sower4GS wrote:
At 7/18/2013 2:41:16 PM, 000ike wrote:
At 7/18/2013 2:30:52 PM, Subutai wrote:
I'm not sure how much this will help you (you might have to read it a few times, as I have), but here is a good explanation:

Some time before the discovery of quantum mechanics people realized that the connection between light waves and photons must be of a statistical character. What they did not clearly realize, however, was that the wave function gives information about the probability of one photon being in a particular place and not the probable number of photons in that place. The importance of the distinction can be made clear in the following way. Suppose we have a beam of light consisting of a large number of photons split up into two components of equal intensity. On the assumption that the beam is connected with the probable number of photons in it, we should have half the total number going into each component. If the two components are now made to interfere, we should require a photon in one component to be able to interfere with one in the other. Sometimes these two photons would have to annihilate one another and other times they would have to produce four photons. This would contradict the conservation of energy. The new theory, which connects the wave function with probabilities for one photon gets over the difficulty by making each photon go partly into each of the two components. Each photon then interferes only with itself. Interference between two different photons never occurs.(Dirac)

Sources

Paul Dirac, The Principles of Quantum Mechanics, Fourth Edition, Chapter 1

thank you. That really helps. But I'm just curious: Is it also a valid objection (to the concept of 2 different photons interfering) that if interference were dependent on the influence of another photon, then as individual photons were fired through the double slit, they would not show interference lines and instead distribute randomly? This is what confused me in the first place.

Air max is ticked, I believe He or She (duno really never met em) is a Jew.

Yeah, so? You do know that Jesus was a Jew, and if you believe he was the incarnation of God, then YHWH was Jewish too.

YHWH is convicting Him the Maschiach is here and He will have none of it. I will be back after a while. In the mean-time Seek truth in Scripture, YHWH may close this door the the seed He has planted through His servant Sower For the Good Sheppard can grow, I will be back before Ya'acob's Trouble (Tribulation) takes full hold to Reap the Harvest. Shalom.

Look the Father's name, your Creator and His Son are ONE.
YHWH means "Set apart" ok? Not from this Earth. He Created it and you and everything. Simple. Yet He is Awesome.

That is why people cannot comprehend him and demand proof First, well it does not work that way. Trust first, make a decision, then Blessings. Salvation and the whole Whammy follow.

See you all around, As the Governor of Cali said once "I'll be back" For Intellectuals you sure are a rowdy bunch. If YHWH was not convicting the socks off of you then you would all of actually found me quite funny and likable. But it is not about me, now is it.

No, it was about quantum physics.

My name is Yohanan. It means John in English and YHWH is Gracious. Bye you guys....hahaha I had some good laughs.

What on earth does this have to do with the double slit experiment? What does it have to do with anything?
"It is one of the commonest of mistakes to consider that the limit of our power of perception is also the limit of all there is to perceive." " C. W. Leadbeater
the_croftmeister
Posts: 678
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7/21/2013 5:59:13 PM
Posted: 3 years ago
Could anyone explain how QM is opposed to realism (local or non-local) or materialism? I understand the opposition to determinism (though I see it as hardly conclusive).
Enji
Posts: 1,022
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7/21/2013 6:33:52 PM
Posted: 3 years ago
At 7/21/2013 5:59:13 PM, the_croftmeister wrote:
Could anyone explain how QM is opposed to realism (local or non-local) or materialism? I understand the opposition to determinism (though I see it as hardly conclusive).

John Bell (and others since) derived certain inequalities which must be met if local realism is true; QM experiments violate these inequalities, consequently local realism is false. [http://en.wikipedia.org...]
the_croftmeister
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7/21/2013 6:45:45 PM
Posted: 3 years ago
At 7/21/2013 6:33:52 PM, Enji wrote:
At 7/21/2013 5:59:13 PM, the_croftmeister wrote:
Could anyone explain how QM is opposed to realism (local or non-local) or materialism? I understand the opposition to determinism (though I see it as hardly conclusive).

John Bell (and others since) derived certain inequalities which must be met if local realism is true; QM experiments violate these inequalities, consequently local realism is false. [http://en.wikipedia.org...]

Ah sorry, when there was mention of realism I started thinking of philosophical realism, yes, I understand this particular result. Any ideas on materialism?
Enji
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7/21/2013 6:53:14 PM
Posted: 3 years ago
At 7/21/2013 6:45:45 PM, the_croftmeister wrote:
At 7/21/2013 6:33:52 PM, Enji wrote:
At 7/21/2013 5:59:13 PM, the_croftmeister wrote:
Could anyone explain how QM is opposed to realism (local or non-local) or materialism? I understand the opposition to determinism (though I see it as hardly conclusive).

John Bell (and others since) derived certain inequalities which must be met if local realism is true; QM experiments violate these inequalities, consequently local realism is false. [http://en.wikipedia.org...]

Ah sorry, when there was mention of realism I started thinking of philosophical realism, yes, I understand this particular result. Any ideas on materialism?

It doesn't. At best, I suppose you could argue that materialism is not sufficient to explain the non-locality of quantum mechanics.
Such
Posts: 1,110
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7/21/2013 6:56:07 PM
Posted: 3 years ago
At 7/18/2013 2:25:17 PM, 000ike wrote:
Alright, so they fire a beam of light through two slits, it diffracts, the two separate waves constructively and destructively interfere, and so the there's something like a serrated pattern of intense light and no light at all on the screen. That's easy enough to digest.

It's not quite intense light and no light at all, but rather, an alternating pattern of bright light and dimmer light.

What's making my head spin is how they receive the same results when they fire individual photons or electrons. The explanation is that the electromagnetic wave represents a probability distribution, and where the wave is constructively amplified, the particle is most likely to land, the reverse for the destructively diminished portions of the wave. But the interference is dependent on the interaction of two separate waves. If you fire a photon/electron individually, there's no other wave-like particle to offer the interference (as there would be , so how does the same pattern emerge??

Am I right in thinking that the single photon is a wave that passes through both slits and then diffracts and interferes with itself (whatever that means)?

No, I believe this is incorrect.

As far as I know, scientists have never isolated the trajectory of single photons. It's impossible to see photons, as the human ocular makeup require photons to see. Likewise, it's impossible to detect single photons, only the starting and ending point of a hypothetical photon.

There is a probability distribution for electromagnetic or photonic waves (or, any wave, for that matter), but they refer to that hypothetical trajectory I was just talking about. There are actual distributions for given light waves of given frequencies (or colors, in terms of the visual spectrum).

Moreover, photons do not interact with themselves, per se. The interference pattern exemplified in the Double-Slit Experiment occurs with all waves that interact with one another. A beam of light passing through a slit will result in a pattern that looks almost like a splash a photons, perhaps akin to a shotgun.

If a beam of light were to pass over on object, on the other hand, then diffusion will result, and this is also due to the interference of several waves, rather than one, as passing over the object will divide a single wave into several.

Here is a picture that illustrates the above: http://abyss.uoregon.edu...

Here is a video, using water as an example:
the_croftmeister
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7/21/2013 6:59:02 PM
Posted: 3 years ago
At 7/21/2013 6:53:14 PM, Enji wrote:
At 7/21/2013 6:45:45 PM, the_croftmeister wrote:
At 7/21/2013 6:33:52 PM, Enji wrote:
At 7/21/2013 5:59:13 PM, the_croftmeister wrote:
Could anyone explain how QM is opposed to realism (local or non-local) or materialism? I understand the opposition to determinism (though I see it as hardly conclusive).

John Bell (and others since) derived certain inequalities which must be met if local realism is true; QM experiments violate these inequalities, consequently local realism is false. [http://en.wikipedia.org...]

Ah sorry, when there was mention of realism I started thinking of philosophical realism, yes, I understand this particular result. Any ideas on materialism?

It doesn't. At best, I suppose you could argue that materialism is not sufficient to explain the non-locality of quantum mechanics.

Ok good, so it's not just me.
Enji
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7/21/2013 7:00:16 PM
Posted: 3 years ago
At 7/21/2013 6:59:02 PM, the_croftmeister wrote:
At 7/21/2013 6:53:14 PM, Enji wrote:
At 7/21/2013 6:45:45 PM, the_croftmeister wrote:
At 7/21/2013 6:33:52 PM, Enji wrote:
At 7/21/2013 5:59:13 PM, the_croftmeister wrote:
Could anyone explain how QM is opposed to realism (local or non-local) or materialism? I understand the opposition to determinism (though I see it as hardly conclusive).

John Bell (and others since) derived certain inequalities which must be met if local realism is true; QM experiments violate these inequalities, consequently local realism is false. [http://en.wikipedia.org...]

Ah sorry, when there was mention of realism I started thinking of philosophical realism, yes, I understand this particular result. Any ideas on materialism?

It doesn't. At best, I suppose you could argue that materialism is not sufficient to explain the non-locality of quantum mechanics.

Ok good, so it's not just me.

I would like to read what RT says about that though.
the_croftmeister
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7/21/2013 7:06:58 PM
Posted: 3 years ago
As far as I know, scientists have never isolated the trajectory of single photons. It's impossible to see photons, as the human ocular makeup require photons to see. Likewise, it's impossible to detect single photons, only the starting and ending point of a hypothetical photon.
Well the point of QM is that there is no 'trajectory'. Even a single photon travels as a wave. Though we have done this experiment with electrons, and detected which slit they pass through as they do. What this means though is that we effectively collapse the wavefunction at the slit, rather than at the screen and then allow the electron to continue travelling as a wave and then be collapsed again once it reaches the screen.

There is a probability distribution for electromagnetic or photonic waves (or, any wave, for that matter), but they refer to that hypothetical trajectory I was just talking about. There are actual distributions for given light waves of given frequencies (or colors, in terms of the visual spectrum).

Moreover, photons do not interact with themselves, per se.
I'm not sure what you mean by that? There is one photon that travels as a wave. It interferes with itself. How is this not the photon interacting with itself?

The interference pattern exemplified in the Double-Slit Experiment occurs with all waves that interact with one another. A beam of light passing through a slit will result in a pattern that looks almost like a splash a photons, perhaps akin to a shotgun.
Such
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7/21/2013 7:31:34 PM
Posted: 3 years ago
At 7/21/2013 7:06:58 PM, the_croftmeister wrote:
As far as I know, scientists have never isolated the trajectory of single photons. It's impossible to see photons, as the human ocular makeup require photons to see. Likewise, it's impossible to detect single photons, only the starting and ending point of a hypothetical photon.
Well the point of QM is that there is no 'trajectory'. Even a single photon travels as a wave. Though we have done this experiment with electrons, and detected which slit they pass through as they do. What this means though is that we effectively collapse the wavefunction at the slit, rather than at the screen and then allow the electron to continue travelling as a wave and then be collapsed again once it reaches the screen.

I don't think that travelling in a wavelike formation belies a trajectory. A trajectory is essentially a curve.

There have been several Double-Slit experiments, both with photons and electrons, but the most famous was with photons, as it was with a beam of light. Electromagnetic waves do behave the same, but all substances behave the same, really, as all substance are reducible to particles, and all particles travel as waves.

According to explanations of the Schrodinger Equation, wave functions don't collapse when it experiences interference. The collapse of a wave function occurs when a given moving body is measured. Until this measurement occurs, that moving body is in all possible locations in superposition.

For a free particle, all a wave function will accept about its actual state is its momentum. To determine its location, its momentum must be reduced to zero for a given interval.

There is a probability distribution for electromagnetic or photonic waves (or, any wave, for that matter), but they refer to that hypothetical trajectory I was just talking about. There are actual distributions for given light waves of given frequencies (or colors, in terms of the visual spectrum).

Moreover, photons do not interact with themselves, per se.
I'm not sure what you mean by that? There is one photon that travels as a wave. It interferes with itself. How is this not the photon interacting with itself?

A single wave cannot interfere with itself. Perhaps I don't understand what you mean -- can you expound, please?
the_croftmeister
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7/21/2013 8:57:02 PM
Posted: 3 years ago
At 7/21/2013 7:31:34 PM, Such wrote:
At 7/21/2013 7:06:58 PM, the_croftmeister wrote:
As far as I know, scientists have never isolated the trajectory of single photons. It's impossible to see photons, as the human ocular makeup require photons to see. Likewise, it's impossible to detect single photons, only the starting and ending point of a hypothetical photon.
Well the point of QM is that there is no 'trajectory'. Even a single photon travels as a wave. Though we have done this experiment with electrons, and detected which slit they pass through as they do. What this means though is that we effectively collapse the wavefunction at the slit, rather than at the screen and then allow the electron to continue travelling as a wave and then be collapsed again once it reaches the screen.

I don't think that travelling in a wavelike formation belies a trajectory. A trajectory is essentially a curve.
I think you are missing the point. The particles do not 'exist' between detections. The photons do not travel in a wave like 'formation', they are waves. When you detect them however, all the energy involved in the wave is absorbed at one point (like a particle). At least this is the standard explanation. The fact that light waves only get absorbed in 'packets' called photons is one of the wonderous parts of quantum mechanics and has a mathematical explanation (to do with standing waves and such).

There have been several Double-Slit experiments, both with photons and electrons, but the most famous was with photons, as it was with a beam of light. Electromagnetic waves do behave the same, but all substances behave the same, really, as all substance are reducible to particles, and all particles travel as waves.
More to the point, there are no particles between interactions, only waves.

According to explanations of the Schrodinger Equation, wave functions don't collapse when it experiences interference. The collapse of a wave function occurs when a given moving body is measured. Until this measurement occurs, that moving body is in all possible locations in superposition.
No, there is no collapse on interference, but there is when detection occurs, which is what happens when you try to detect which slit the photon or electron went through.

For a free particle, all a wave function will accept about its actual state is its momentum. To determine its location, its momentum must be reduced to zero for a given interval.
The momentum is not reduced to zero, it is made 'indeterminate'. The operator that calculates the momentum no longer yields an eigenvalue when applied to the wavefunction.

There is a probability distribution for electromagnetic or photonic waves (or, any wave, for that matter), but they refer to that hypothetical trajectory I was just talking about. There are actual distributions for given light waves of given frequencies (or colors, in terms of the visual spectrum).
The probability distribution is obtained from the wavefunction which 'is' the light. The particles are an artefact of how the light interacts with matter.

Moreover, photons do not interact with themselves, per se.
I'm not sure what you mean by that? There is one photon that travels as a wave. It interferes with itself. How is this not the photon interacting with itself?

A single wave cannot interfere with itself. Perhaps I don't understand what you mean -- can you expound, please?
Well there is no notion of plurality or singularity that makes sense for waves. Do you mean multiple sources of the wave? The number of photons in the wave is a measure of the intensity of the wave. A two photon wave is twice as intense as a one photon wave and so on. It's still one wave, but it has enough energy to be detected in multiple places.
Such
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7/21/2013 11:21:50 PM
Posted: 3 years ago
At 7/21/2013 8:57:02 PM, the_croftmeister wrote:
I think you are missing the point. The particles do not 'exist' between detections. The photons do not travel in a wave like 'formation', they are waves. When you detect them however, all the energy involved in the wave is absorbed at one point (like a particle). At least this is the standard explanation. The fact that light waves only get absorbed in 'packets' called photons is one of the wonderous parts of quantum mechanics and has a mathematical explanation (to do with standing waves and such).

Either I don't understand your explanation, or your contradicting contemporary science. Photons are, in fact, particles. They are analogous to, perhaps, grains of sand. They aren't "absorbed" as packets, they exist as packets, as described by Planck's Constant.

Drawing from the grains of sand analogy, sand generally does not accumulate into a flat plane. When strewn about, it will always lay in modular fashion -- whether in dunes throughout expansive deserts, or with shallow ripples and waves in a sand box. It appears as though you're equivocating sand dunes and grains of sand, which is an error.

Photons travel in waves, but are actually particles, much like electrons, which also travel in waves, but are likewise particles (that revolve around atoms, no less).

More to the point, there are no particles between interactions, only waves.

Actually, that's entirely false; you're completely ignoring an entire half of the Double-Slit experiment, which is what ultimately gives it meaning.

You see, when scientists shoot a beam of light through a single slit, the photons behave like particles, dispersing in wave-like fashion, but splattering on the photosensitive plate detecting them in the way pellets from a shotgun disperse on a target. Accordingly, it acts consistent with a wave-like trajectory, with a concentrated center and dispersed out-edges, but the furthest reaches of the edges will show individual dots -- particles -- dispersed so far away from one another, they're distinguishable. In this way, the photons behave more like particles than they do waves.

However, when a single beam of light (or two beams of light, for that matter) are shot through two slits, the result is a pattern of varying colors and intensities on the photosensitive plate detecting the photons, which is essentially a wave pattern. From this resulted in the particle-wave dual interpretation of photons, which later led to the understanding that all particles as we know they travel as waves (unless they're revolving around something).

No, there is no collapse on interference, but there is when detection occurs, which is what happens when you try to detect which slit the photon or electron went through.

Yes... but, that is given the device used to detect such a trajectory, which must minimize momentum in order to determine position (freeze a Planck frame, if you will).

The momentum is not reduced to zero, it is made 'indeterminate'. The operator that calculates the momentum no longer yields an eigenvalue when applied to the wavefunction.

Am I incorrect by believing that you're drawing this entirely from Wikipedia?

That article regarding the Wave Function is generally imprecise and only mostly correct.

There is an inverse relationship between the knowledge scientists can determine about position and momentum, but this is because it requires that momentum is reduced in order to determine position. You must understand that something traveling at terminal speed cannot be measured in real time, given it is impossible to keep up with it. Therefore, one must somehow reduce the speed at which its travelling in order to detect it at all.

There is nothing that humans possess that operate at the speed of light, and we cannot think or process at the speed of light. Therefore, it is impossible to detect something at the speed of light.

We must, instead, slow a photon down somehow, in order to determine an estimated location, or stop it completely for a precise location.

The probability distribution is obtained from the wavefunction which 'is' the light. The particles are an artefact of how the light interacts with matter.

You have this backwards, I believe.

Particles are light, and the wave function is an artefact of how light interacts with matter (and travels through a plane).

The wave function is only a mathematical explanation, after all, whereas photons are an empirical observation.

Well there is no notion of plurality or singularity that makes sense for waves. Do you mean multiple sources of the wave? The number of photons in the wave is a measure of the intensity of the wave. A two photon wave is twice as intense as a one photon wave and so on. It's still one wave, but it has enough energy to be detected in multiple places.

Hmm... what do you mean, "makes sense of the waves?"

Waves are, I think, a form of conveyance. You see, humans initially believed, erroneously, that particles travel in the quantum universe as they do in the macro universe, i.e., in direct, straight vectors. What they failed to realize, though, is that there is no such thing as direct, straight vectors, unless its in a vacuum. A ball thrown, for example, is really curving against the earth.

But, lets say we're talking about space. Well, the entire composite of a ball would travel in a straight vector, as would a beam of light. The particles that comprise the ball, on the other hand, would travel in a wave, as would the photons that comprise a beam of light.
the_croftmeister
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7/21/2013 11:51:25 PM
Posted: 3 years ago
At 7/21/2013 11:21:50 PM, Such wrote:
At 7/21/2013 8:57:02 PM, the_croftmeister wrote:
I think you are missing the point. The particles do not 'exist' between detections. The photons do not travel in a wave like 'formation', they are waves. When you detect them however, all the energy involved in the wave is absorbed at one point (like a particle). At least this is the standard explanation. The fact that light waves only get absorbed in 'packets' called photons is one of the wonderous parts of quantum mechanics and has a mathematical explanation (to do with standing waves and such).

Either I don't understand your explanation, or your contradicting contemporary science. Photons are, in fact, particles. They are analogous to, perhaps, grains of sand. They aren't "absorbed" as packets, they exist as packets, as described by Planck's Constant.
Well then we will have to agree to disagree, I am looking at my third year physics textbook and it definitely says that light is a wave during transport and is a particle on absorption by an electron. The electrons are waves inhabiting the space around the nucleus (there is no orbiting involved as evidenced by the fact that s-shell electrons have 0 angular momentum and this has been experimentally confirmed).

Drawing from the grains of sand analogy, sand generally does not accumulate into a flat plane. When strewn about, it will always lay in modular fashion -- whether in dunes throughout expansive deserts, or with shallow ripples and waves in a sand box. It appears as though you're equivocating sand dunes and grains of sand, which is an error.
Nope, you are making the false assumption that I am asserting that what appears like a particle is always a particle, and that what appears like a wave is always a wave. In fact, I am stating that light and matter are neither, and cannot be understood as either one on their own. The standard conception in physics (from my undergrad course) is that light and matter are not waves that sometimes act like particles nor particles that sometimes act like waves. They are both waves and particles depending on how you look at them. More to the point, when you aren't looking they are waves, and when you are they are particles.

Photons travel in waves, but are actually particles, much like electrons, which also travel in waves, but are likewise particles (that revolve around atoms, no less).
See above, neither are particles, neither are waves, this is the very essence of the wave-particle duality.

More to the point, there are no particles between interactions, only waves.

Actually, that's entirely false; you're completely ignoring an entire half of the Double-Slit experiment, which is what ultimately gives it meaning.
Which half?

You see, when scientists shoot a beam of light through a single slit, the photons behave like particles, dispersing in wave-like fashion, but splattering on the photosensitive plate detecting them in the way pellets from a shotgun disperse on a target.
No, they still behave like a wave, even when through a single slit, it's just that the differences are far less pronounced. Interference still occurs through a single slit (I know because I have done the experiment).

Accordingly, it acts consistent with a wave-like trajectory, with a concentrated center and dispersed out-edges, but the furthest reaches of the edges will show individual dots -- particles -- dispersed so far away from one another, they're distinguishable. In this way, the photons behave more like particles than they do waves.
They only behave like particles when they hit the screen, being absorbed by only one electron rather than spread out over the entire screen.

However, when a single beam of light (or two beams of light, for that matter) are shot through two slits, the result is a pattern of varying colors and intensities on the photosensitive plate detecting the photons, which is essentially a wave pattern. From this resulted in the particle-wave dual interpretation of photons, which later led to the understanding that all particles as we know they travel as waves (unless they're revolving around something).
Perhaps you should try the single slit experiment yourself.

No, there is no collapse on interference, but there is when detection occurs, which is what happens when you try to detect which slit the photon or electron went through.

Yes... but, that is given the device used to detect such a trajectory, which must minimize momentum in order to determine position (freeze a Planck frame, if you will).
Momentum doesn't stop. Photons (or their respective waves rather) always travel at the speed of light, the detection occurs as a result of absorption by an electron (creating a current which can be detected) and reemission of the photon (usually at a longer wavelength due to lost energy).

The momentum is not reduced to zero, it is made 'indeterminate'. The operator that calculates the momentum no longer yields an eigenvalue when applied to the wavefunction.

Am I incorrect by believing that you're drawing this entirely from Wikipedia?

That article regarding the Wave Function is generally imprecise and only mostly correct.
Yes you are incorrect, I am reading from my third year physics text.

The probability distribution is obtained from the wavefunction which 'is' the light. The particles are an artefact of how the light interacts with matter.

You have this backwards, I believe.
Could you source this for me then? I have heard of 'wavefunction guide theories' but was never exposed to them at university.

Particles are light, and the wave function is an artefact of how light interacts with matter (and travels through a plane).
I'm a little confused, the wavefunction is only present when the light is not interacting with matter i.e. in the air travelling between source and detector. How do wave properties result from interactions with matter?

The wave function is only a mathematical explanation, after all, whereas photons are an empirical observation.
I'm pretty sure the entire purpose of the double slit experiment is an empirical observation of the wavefunction.

Well there is no notion of plurality or singularity that makes sense for waves. Do you mean multiple sources of the wave? The number of photons in the wave is a measure of the intensity of the wave. A two photon wave is twice as intense as a one photon wave and so on. It's still one wave, but it has enough energy to be detected in multiple places.

Hmm... what do you mean, "makes sense of the waves?"
That phrase wasn't in my paragraph, what exactly are you asking?

Waves are, I think, a form of conveyance. You see, humans initially believed, erroneously, that particles travel in the quantum universe as they do in the macro universe, i.e., in direct, straight vectors. What they failed to realize, though, is that there is no such thing as direct, straight vectors, unless its in a vacuum. A ball thrown, for example, is really curving against the earth.
Now you are talking about general relativity, which has not even been reconciled with quantum mechanics successfully yet. QM and GR are independent theories that do not depend on each other. What does this have to do with the wave-particle duality?

But, lets say we're talking about space. Well, the entire composite of a ball would travel in a straight vector, as would a beam of light. The particles that comprise the ball, on the other hand, would travel in a wave, as would the photons that comprise a beam of light.
I'm pretty sure that the only reason the ball travels in a straight line is because of the electromagnetic interactions of its constituent particles. The ball still has (and is) a wavefunction, it just has an incredibly short wavelength.
Rational_Thinker9119
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7/22/2013 3:48:42 AM
Posted: 3 years ago
At 7/21/2013 6:33:52 PM, Enji wrote:
At 7/21/2013 5:59:13 PM, the_croftmeister wrote:
Could anyone explain how QM is opposed to realism (local or non-local) or materialism? I understand the opposition to determinism (though I see it as hardly conclusive).

John Bell (and others since) derived certain inequalities which must be met if local realism is true; QM experiments violate these inequalities, consequently local realism is false. [http://en.wikipedia.org...]

It's not just local realism that is false. Leggett's inequalities being violated proves that non-local realism is false as well. The before-before experiment closes all loopholes out of that conclusion. I am not sure how a Realist picture of reality could be compatible with quantum mechanics.