Questions for MysticPhd (purpose, interpretation, quote, versus)

[MysticPhD]

Originally Posted by Morbert

[edit]- Ok, I think I have identified the misunderstanding. When I say the probability that the signal photon will be detected at location L on the detector screen is independent of the idle photon, I don't mean they are not entangled. They are absolutely entangled. But entanglement is a correlation, not a causal relation. You cannot affect one entangled particle by interfering with another. If you could, we would have faster-than-light communication.
I think it might be worth me dedicating a post to describing entanglement, which I will do when I get the chance.

Originally Posted by Cruithne

I discussed quantum entanglement with Hiker earlier in the thread.

And I agreed with all of it. My issue is with Morbert's seeming refutation of the key aspects of entanglement. Morbert seems to be refuting what you and your sources said:

"It's a bit complicated but basically all you need to know is 2 particles (these can be photons or other types of particle) become 'entangled' with each other. The movement of one determines the movement of the other even though they are physically separated. There doesn't to be any restriction on how far apart the particles are away from each other and the effects seem to be instantaneous."

"Quantum entanglement can be defined like this: In quantum physics, entangled particles remain connected so that actions performed on one affect the other, even when separated by great distances. The phenomenon so riled Albert Einstein he called it "spooky action at a distance."

The results are particularly difficult to explain in the delayed quantum eraser experiments giving the erroneous appearance of retro-causality, Cruithne . . . which is why I await Morbert's clarification.

Originally Posted by Cruithne

Seems to me there are a variety of things being discussed in this thread.
I think its okay for me to chip in and put my point of view across about a particular issue that I thought needed clarifying. Actually I think it was an important point to make.
I understand where you are coming from here. The brain is a complex network of nerve cells, transmitting electrochemical signals to other areas of the brain responsible for functions such as cognition, memory, attention, perception, emotion and the senses. So I get what you are saying about consciousness suggesting a thermodynamic process. But given that even all we know about the structure and systems within the brain, we still don't know how all of that actually gives rise to consciousness so the operative word here is suggest.
In any case, since quantum physics encompasses the study of all matter and energy at a quantum level, we seem to be in agreement anyway, since my point was that consciousness must exist with the physical laws of nature and quantum to me seems to be the only way to go.

I would agree . . . with the caveat that consciousness is PRODUCED with the physics we currently know and measure. I am not as sanguine about its locus. The unified field is the dominant aspect establishing our reality and I believe consciousness once produced is identical with it.

Originally Posted by Cruithne

Where we differ is here:
On this point I side with Penroses stance that the brain-as-computer view fails to account for things like:
* Distinctions between conscious and non-conscious.
* 'Non-computable' thought and understanding.
* 'Binding and synchrony', the problem of how disparate neuronal activities are bound into unified conscious experience.
* Measurable brain activity corresponding to a stimulus often occurs after we've responded (seemingly consciously) to that stimulus.

I agree and the most inexplicable aspect of human consciousness as a purely brain-resident phenomenon is subjective experience and self-reflection. The entire brain is responsible for the state of consciousness. A state machine cannot simultaneously represent the state and the reflection upon the state without disrupting the former.

[Morbert]

On this point I side with Penroses stance that the brain-as-computer view fails to account for things like:
* Distinctions between conscious and non-conscious.

His postulates only address matters of computability, not the existence of consciousness itself. Consciousness emerging from a information processing system that exploits non-computable features of quantum gravity seems just as strange as it emerging from a system that doesn't. The p-zombie hypothesis is applicable to both. ( http://en.wikipedia.org/wiki/P-zombie ). I am open to correction on this. I have read The Emperor's New Mind. I have Shadows of the Mind but I have not read it yet.

* 'Non-computable' thought and understanding.

But is there non-computable thought and understanding?

* 'Binding and synchrony', the problem of how disparate neuronal activities are bound into unified conscious experience.

But disparate neuronal activities are not bound into unified conscious experience, which is why you and I are not the same consciousness. Furthermore, when disparate neuronal activity exists in a brain, it causes all sorts of strange phenomena with consciousness.

Alien Hand, Discovery - YouTube

* Measurable brain activity corresponding to a stimulus often occurs after we've responded (seemingly consciously) to that stimulus.

That seems perfectly normal. A computer can execute processing well after it has received stimulus.

[Morbert]

And I agreed with all of it. My issue is with Morbert's seeming refutation of the key aspects of entanglement. Morbert seems to be refuting what you and your sources said:

"It's a bit complicated but basically all you need to know is 2 particles (these can be photons or other types of particle) become 'entangled' with each other. The movement of one determines the movement of the other even though they are physically separated. There doesn't to be any restriction on how far apart the particles are away from each other and the effects seem to be instantaneous."

"Quantum entanglement can be defined like this: In quantum physics, entangled particles remain connected so that actions performed on one affect the other, even when separated by great distances. The phenomenon so riled Albert Einstein he called it "spooky action at a distance."

The results are particularly difficult to explain in the delayed quantum eraser experiments giving the erroneous appearance of retro-causality, Cruithne . . . which is why I await Morbert's clarification.

When people say the photons in the delayed-choice quantum eraser are entangled, what they mean is the signal photons of the idler photons that strike detectors D1 (or D2), as defined here Delayed choice quantum eraser - Wikipedia, the free encyclopedia, will exhibit an interference pattern, while the signal photons of the idler photons that strike D3 (or D4) won't.

The reason this entanglement doesn't imply causation is because anything that happens to the signal photon is independent of anything that happens to the idler photon. You cannot manipulate the idler photon to affect where the signal photon goes, or vice versa.

An alternative description is: If you pick a point on the detector screen and ask "What is the probability that a signal photon will strike this area?", the answer not at all affected by what happens to the idler photon.

[MysticPhD]

Originally Posted by MysticPhD

And I agreed with all of it. My issue is with Morbert's seeming refutation of the key aspects of entanglement. Morbert seems to be refuting what you and your sources said:

"It's a bit complicated but basically all you need to know is 2 particles (these can be photons or other types of particle) become 'entangled' with each other. The movement of one determines the movement of the other even though they are physically separated. There doesn't to be any restriction on how far apart the particles are away from each other and the effects seem to be instantaneous."

"Quantum entanglement can be defined like this: In quantum physics, entangled particles remain connected so that actions performed on one affect the other, even when separated by great distances. The phenomenon so riled Albert Einstein he called it "spooky action at a distance."

The results are particularly difficult to explain in the delayed quantum eraser experiments giving the erroneous appearance of retro-causality, Cruithne . . . which is why I await Morbert's clarification.

I would agree . . . with the caveat that consciousness is PRODUCED with the physics we currently know and measure. I am not as sanguine about its locus. The unified field is the dominant aspect establishing our reality and I believe consciousness once produced is identical with it.
I agree and the most inexplicable aspect of human consciousness as a purely brain-resident phenomenon is subjective experience and self-reflection. The entire brain is responsible for the state of consciousness. A state machine cannot simultaneously represent the state and the reflection upon the state without disrupting the former.

Originally Posted by Morbert

When people say the photons in the delayed-choice quantum eraser are entangled, what they mean is the signal photons of the idler photons that strike detectors D1 (or D2), as defined here Delayed choice quantum eraser - Wikipedia, the free encyclopedia, will exhibit an interference pattern, while the signal photons of the idler photons that strike D3 (or D4) won't.The reason this entanglement doesn't imply causation is because anything that happens to the signal photon is independent of anything that happens to the idler photon. You cannot manipulate the idler photon to affect where the signal photon goes, or vice versa.

Duh! That's IT???? A Wiki describing the experiment??? The signal and idler photons ARE entangled so they exhibit the SAME properties. In the delayed scenario . . . the idler photons display the same properties as their entangled signal photons but BEFORE the fact of detection or not. This implies that they contain the same information regarding whether the signals were detected or not . . . without themselves having been detected!

You have made assertions about entanglement that are contrary to everything I have ever read or known about quantum entanglement and you have provided no support or explanation for your view. Neither have you explained the paradox of the delayed quantum eraser. I begin to doubt your claims of special knowledge. Cruithne seems to know more about this than you have exhibited.

An alternative description is: If you pick a point on the detector screen and ask "What is the probability that a signal photon will strike this area?", the answer not at all affected by what happens to the idler photon.

Huh?? This makes no sense. What happens is the photons are either affected by detection . . . in which case they exhibit the classic pattern . . . or they are not detected and exhibit the interference pattern. The delayed experiment using entangled photons exhibiting the same properties reveal that the idler phtons exhibit the same properties and present the same pattern as their signal photon counterparts . . . but BEFORE their counterparts encounter either the detector or not. Claiming in effect that they are not entangled is pure bunkum!

[Morbert]

Originally Posted by MysticPhD

Duh! That's IT???? A Wiki describing the experiment??? The signal and idler photons ARE entangled so they exhibit the SAME properties. In the delayed scenario . . . the idler photons display the same properties as their entangled signal photons but BEFORE the fact of detection or not. This implies that they contain the same information regarding whether the signals were detected or not . . . without themselves having been detected!

You have made assertions about entanglement that are contrary to everything I have ever read or known about quantum entanglement and you have provided no support or explanation for your view. Neither have you explained the paradox of the delayed quantum eraser. I begin to doubt your claims of special knowledge. Cruithne seems to know more about this than you have exhibited.

Huh?? This makes no sense. What happens is the photons are either affected by detection . . . in which case they exhibit the classic pattern . . . or they are not detected and exhibit the interference pattern. The delayed experiment using entangled photons exhibiting the same properties reveal that the idler phtons exhibit the same properties and present the same pattern as their signal photon counterparts . . . but BEFORE their counterparts encounter either the detector or not. Claiming in effect that they are not entangled is pure bunkum!

You continue to exhibit a monumentally frustrating lack of familiarity with the subjects you are so eager to bring up.

I have repeatedly told you that nobody is saying the photons aren't entangled. Do you understand this? Nobody is saying the photons aren't entangled. Again: Nobody is saying the photons aren't entangled. Once more: Nobody is saying the photons aren't entangled.

But (And this is the part you seem to have trouble with) just because the photons are entangled doesn't mean they are causally connected. One cannot be affected by something that happens to the other. If you want to know the probability of a signal photon striking a location L on the detector screen, it is in no way affected by whether or not you decide to also measure the idler photon. This is a very basic, uncontroversial fact of the experiment, and if you reject even this much, then you reject the results of the entire experiment. I.e. If you switched D1, D2, D3 and D4 off, you would get the exact same pattern as if you turned them on (namely, a classical pattern). If someone barged into the lab mid-experiment and ripped out all the idler photon detectors, it would not change the pattern of the signal photons.

So the signal photons are not affected by any (or no) detection of the idler photons. Again: The signal photons are not affected by any (or no) detection of the idler photons. For good measure: The signal photons are not affected by any (or no) detection of the idler photons.

If the signal photons were affected by detection of the idler photons, that would mean they are causally connected and relativity would be violated. But relativity is not violated because the signal photons are not affected by any (or no) detection of the idler photons.

From the Wikipedia article you said "duh" to but evidently did not read:
"The total pattern of signal photons at the primary detector never shows interference, so it is not possible to deduce what will happen to the idler photons by observing the signal photons alone, which would open up the possibility of gaining information faster-than-light (since one might deduce this information before there had been time for a message moving at the speed of light to travel from the idler detector to the signal photon detector) or even gaining information about the future (since as noted above, the signal photons may be detected at an earlier time than the idlers), both of which would qualify as violations of causality in physics. The apparatus under discussion here could not communicate information in a retro-causal manner because it takes another signal, one which must arrive via a process that can go no faster than the speed of light, to sort the superimposed data in the signal photons into four streams that reflect the states of the idler photons at their four distinct detection screens."

The signal photons are not affected by any (or no) detection of the idler photons.

[MysticPhD]

Originally Posted by Morbert

You continue to exhibit a monumentally frustrating lack of familiarity with the subjects you are so eager to bring up.

More ad hominem assertions without support. Let's stop this nonsense with Wiki . . . which is notoriously unreliable and deal with a known delayed quantum eraser experiment in the peer reviewed literature. I invite you to read it for yourself to make sure you are acquainted with the details.

Yoon-Ho Kim, et al., "A Delayed Choice Quantum Eraser" Phys.Rev.Lett. 84 (2000) 1-5

I will just present a summary of the results beginning when the incoming photon from the laser generates an entangled pair at the crystal.

Time 1. The entangled pair leaves either region A or region B of the crystal. The signal photon heads off to detector D0, and the idler photon heads off to the interferometer.

Time 2. The signal photon is registered and scanned at detector D0 according to its position. This information (the position of the signal photon upon "impact" at D0) is sent on its way to the Coincidence Circuit.

Time 3. The idler photon reaches the first pair of beamsplitters, BSA, BSB. There, QM makes a choice which direction the idler photon will go – either to detectors D3, D4; or to the quantum eraser BS and on to detectors D1, D2.

Time 4a. If the idler photon is shunted to detectors D3, D4, it is detected with which-path information intact. Then and only then do we know which-path information for its twin signal photon that already has been detected, scanned, registered and recorded at D0.

Time 4b. If the idler photon passes through to detectors D1, D2, it is detected with no which-path information (the which-path information having been "erased" at BS).

Time 5. The Coincidence Circuit correlates the arrival of a signal photon at detector D0 with the arrival of its twin at D1, D2, D3, or D4. If the correlation is with an idler arriving at D3 or D4, then we know (after-the-fact) the which-path information of the signal photon that arrived earlier at D0. If the correlation is with an idler arriving at D1 or D2, then we have no which-path information for the signal photon that arrived earlier at D0.

Time 6. Upon accessing the information gathered by the Coincidence Circuit, we the observer are shocked to learn that the pattern shown by the positions registered at D0 at Time 2 depends entirely on the information gathered later at Time 4 and available to us at the conclusion of the experiment.

The position of a photon at detector D0 has been registered and scanned. Yet the actual position of the photon arriving at D0 will be at one place if we later learn more information; and the actual position will be at another place if we do not.

Now you have repeatedly told me a lot of things but supported none of them. I specifically disregarded retro-causality . . . so why you are focused on causation is beyond me. Read the sequence of events in this experiment (check out the original paper if you need to) and explain to me why the results are as reported. How do you interpret the results and explain the implications?

[Morbert]

Originally Posted by MysticPhD

More ad hominem assertions without support. Let's stop this nonsense with Wiki . . . which is notoriously unreliable and deal with a known delayed quantum eraser experiment in the peer reviewed literature. I invite you to read it for yourself to make sure you are acquainted with the details.

This is absolutely ridiculous. You consistently and persistently make incorrect statements, and accuse me of "ad hominem" when I point this out.

Mystic... You do not understand the physical experiment you are trying to use to argue against my perfectly reasonable and uncontroversial claim that observers, as defined in the formalism of quantum mechanics, do not need to be conscious. Until you accept this, the discussion won't go anywhere.

Also, Wikipedia is not "notoriously unreliable". What they say about the detection pattern is true, and not at all contradicted by the paper.

Yoon-Ho Kim, et al., "A Delayed Choice Quantum Eraser" Phys.Rev.Lett. 84 (2000) 1-5

I will just present a summary of the results beginning when the incoming photon from the laser generates an entangled pair at the crystal.

This is what you should have done from the start. It is only now that I can actually see where your understanding of the experiment has gone wrong.

Time 1. The entangled pair leaves either region A or region B of the crystal. The signal photon heads off to detector D0, and the idler photon heads off to the interferometer.

This is not strictly a correct statement (quantum mechanics permits superposition, which is at the heart of the entanglement phenomenon), but it is not the source of your confusion, so I will leave it as it is.

Time 2. The signal photon is registered and scanned at detector D0 according to its position. This information (the position of the signal photon upon "impact" at D0) is sent on its way to the Coincidence Circuit.

Yes, and if we switched off the experiment now, this information would never change. Nothing that happens can affect this recorded position. The position of impact cannot be changed no matter how we measure (or don't measure) the idler photon.

Time 3. The idler photon reaches the first pair of beamsplitters, BSA, BSB. There, QM makes a choice which direction the idler photon will go – either to detectors D3, D4; or to the quantum eraser BS and on to detectors D1, D2.

Time 4a. If the idler photon is shunted to detectors D3, D4, it is detected with which-path information intact. Then and only then do we know which-path information for its twin signal photon that already has been detected, scanned, registered and recorded at D0.

Time 4b. If the idler photon passes through to detectors D1, D2, it is detected with no which-path information (the which-path information having been "erased" at BS).

Time 5. The Coincidence Circuit correlates the arrival of a signal photon at detector D0 with the arrival of its twin at D1, D2, D3, or D4. If the correlation is with an idler arriving at D3 or D4, then we know (after-the-fact) the which-path information of the signal photon that arrived earlier at D0. If the correlation is with an idler arriving at D1 or D2, then we have no which-path information for the signal photon that arrived earlier at D0.

These statements are correct.

Time 6. Upon accessing the information gathered by the Coincidence Circuit, we the observer are shocked to learn that the pattern shown by the positions registered at D0 at Time 2 depends entirely on the information gathered later at Time 4 and available to us at the conclusion of the experiment.

The position of a photon at detector D0 has been registered and scanned. Yet the actual position of the photon arriving at D0 will be at one place if we later learn more information; and the actual position will be at another place if we do not.

This is where you are going wrong. The position of the photon at detector D0 has already been measured at time 2. This recording will not change. If what you said was true (that "the actual position of the photon arriving at D0 will be at one place if we later learn more information; and the actual position will be at another place if we do not.") that would be an example of retrocausality (I.e. A past event affected by our knowledge).

When the authors of the paper talk about interference patterns, they are talking about analysing a subset of the total pattern on D0, and correlating it to the corresponding subset of idler photon detections. (That is what is meant by "joint detection" mentioned in the figures.). This correlation is neat, and classically impossible, but has absolutely nothing to do with your claims regarding consciousness. Knowledge gained about the idler photon can never alter recordings of the signal photon. The total pattern of D0 is always one of no interference (Notice how the authors report a phase shift between Fig 3. and Fig 4. Summing these datapoints, as well as those from the other detectors, gives you the true, interference-free, D0 pattern.)

[MysticPhD]

Originally Posted by Morbert

Mystic... You do not understand the physical experiment you are trying to use to argue against my perfectly reasonable and uncontroversial claim that observers, as defined in the formalism of quantum mechanics, do not need to be conscious. Until you accept this, the discussion won't go anywhere.

I understand it just fine, Morbert . . . I am trying to get you to interpret the implications of it. I know that consciousness is not needed in the detection process . . . but it IS needed in the interpretation of the results. That is what you consistently refuse to deal with . . . focusing instead on criticizing my efforts to do so.

Also, Wikipedia is not "notoriously unreliable". What they say about the detection pattern is true, and not at all contradicted by the paper.

I had no concern for the presentation of the detection patterns . . . just your failure to interpret the implications of them.

This is what you should have done from the start. It is only now that I can actually see where your understanding of the experiment has gone wrong.

I realize that is why you were summoned here . . . to point out where I am wrong in your view. It would be more helpful if you would focus on presenting YOUR view and interpretations of the implications . . . since the actual science is clear. It is the interpretations and implications drawn from it that are in question. We cannot assess the differences using your bald assertions about mine . . . if you do not present your own.

This is not strictly a correct statement (quantum mechanics permits superposition, which is at the heart of the entanglement phenomenon), but it is not the source of your confusion, so I will leave it as it is.

::Sigh::

Yes, and if we switched off the experiment now, this information would never change. Nothing that happens can affect this recorded position. The position of impact cannot be changed no matter how we measure (or don't measure) the idler photon.

DUH! But the INFORMATION that we gather about detection that happened AFTER THE FACT is what produces the paradoxical results.

This is where you are going wrong. The position of the photon at detector D0 has already been measured at time 2. This recording will not change. If what you said was true (that "the actual position of the photon arriving at D0 will be at one place if we later learn more information; and the actual position will be at another place if we do not.") that would be an example of retrocausality (I.e. A past event affected by our knowledge).
When the authors of the paper talk about interference patterns, they are talking about analysing a subset of the total pattern on D0, and correlating it to the corresponding subset of idler photon detections. (That is what is meant by "joint detection" mentioned in the figures.). This correlation is neat, and classically impossible, but has absolutely nothing to do with your claims regarding consciousness.

What DOES it have to do with if not consciousness? If the actual process is a physical one and not an artifact . . . HOW and WHY does information about detection that occurred after the fact change the pattern observed before the detection occurred? It seems to me either the photons are really interfering with each other or not before detection . . . whether or not they have been detected after the fact.

Knowledge gained about the idler photon can never alter recordings of the signal photon. The total pattern of D0 is always one of no interference (Notice how the authors report a phase shift between Fig 3. and Fig 4. Summing these datapoints, as well as those from the other detectors, gives you the true, interference-free, D0 pattern.)

I am asking you to explain and interpret the results and their implications . . . but you are describing the results. One of my favorite lines from "As Good as it Gets" is when Nicholson says "I'm drowning here and you are describing the water." I understand the feeling. Are you EVER going to interpret and explain the implications or not?

[Morbert]

I feel like I am banging my head against a wall here.

Originally Posted by MysticPhD

If the actual process is a physical one and not an artifact . . . HOW and WHY does information about detection that occurred after the fact change the pattern observed before the detection occurred?

It doesn't change the pattern. No pattern is changed. The same pattern is always observed. Please address this.

It seems to me either the photons are really interfering with each other or not before detection . . . whether or not they have been detected after the fact.I am asking you to explain and interpret the results and their implications . . . but you are describing the results. One of my favorite lines from "As Good as it Gets" is when Nicholson says "I'm drowning here and you are describing the water." I understand the feeling. Are you EVER going to interpret and explain the implications or not?

You have incorrectly described the results. No results can be interpreted until you are actually aware of the results. When you say "Yet the actual position of the photon arriving at D0 will be at one place if we later learn more information; and the actual position will be at another place if we do not." you are saying something that is categorically incorrect. The actual position of the photon arriving at D0 will not be at one place if we later learn more information, and another place if we don't. I.e. The pattern on D0 is independent of anything we do to the idler photons. We cannot progress the debate until you accept this fact.

[MysticPhD]

Originally Posted by MysticPhD

I understand it just fine, Morbert . . . I am trying to get you to interpret the implications of it. I know that consciousness is not needed in the detection process . . . but it IS needed in the interpretation of the results. That is what you consistently refuse to deal with . . . focusing instead on criticizing my efforts to do so. I had no concern for the presentation of the detection patterns . . . just your failure to interpret the implications of them. I realize that is why you were summoned here . . . to point out where I am wrong in your view. It would be more helpful if you would focus on presenting YOUR view and interpretations of the implications . . . since the actual science is clear. It is the interpretations and implications drawn from it that are in question. We cannot assess the differences using your bald assertions about mine . . . if you do not present your own.
::Sigh:UH! But the INFORMATION that we gather about detection that happened AFTER THE FACT is what produces the paradoxical results. What DOES it have to do with if not consciousness? If the actual process is a physical one and not an artifact . . . HOW and WHY does information about detection that occurred after the fact change the pattern observed before the detection occurred? It seems to me either the photons are really interfering with each other or not before detection . . . whether or not they have been detected after the fact.I am asking you to explain and interpret the results and their implications . . . but you are describing the results. One of my favorite lines from "As Good as it Gets" is when Nicholson says "I'm drowning here and you are describing the water." I understand the feeling. Are you EVER going to interpret and explain the implications or not?

Originally Posted by Morbert

It doesn't change the pattern. No pattern is changed. The same pattern is always observed. Please address this.

Stop being coy and obfuscating the issue. There ARE two different patterns based on what is done about observing (detecting) and therefore knowing the photon's path through the slits. If we do not know the path we get the interference pattern (wave result). If we know the path we get the particle result. How and why should this be so?

You have incorrectly described the results.

I have correctly described the results. You do not like my interpretation of them . . . and you refuse to provide yours.

No results can be interpreted until you are actually aware of the results.

Nonsense! I am aware of the results. What I need is your interpretation of them . . . if you are capable.

When you say "Yet the actual position of the photon arriving at D0 will be at one place if we later learn more information; and the actual position will be at another place if we do not." you are saying something that is categorically incorrect. The actual position of the photon arriving at D0 will not be at one place if we later learn more information, and another place if we don't. I.e. The pattern on D0 is independent of anything we do to the idler photons. We cannot progress the debate until you accept this fact.

You don't like my phrasing of it . . . I get that. The phrase "actual position" bothers you so use your own phrasing and stop dodging and procrastinating. Can you explain the results however you would characterize them. You agree that two different patterns emerge based on detection versus no detection . . . even though the detection occurred after the fact, right? I am concerned with the appearance of the different results given the time disparity for what is otherwise a purely physical process. Do you get it yet . . . or are you still focused on trying to make me appear ignorant?