Is there any reason this Quantum Telegraph couldn’t work?

[swansont]

6 hours ago, TakenItSeriously said:

You’re both right of course. I mis-wrote my example.

I meant to say that it was the light beam equivalent of an electron positron symmetry that was just easier to represent.

Never the less, the point is that their positions are correlated, i.e. Alice knows the relative positions of both particles. therefore it must produce a dual distribution pattern on both sides.

You aren't going to get an interference pattern with large separation of the slits. And that's the only way that this "which path" scheme works. 

Particle vs wave is not a property that can be entangled. They are not quantum states.

[TakenItSeriously]

1 hour ago, swansont said:

You aren't going to get an interference pattern with large separation of the slits. And that's the only way that this "which path" scheme works. 

What kind of arguement is that? I never said anything about the geometries of the dual slits. It’s assumed that they are the proper size in this thought experiment.

 

 

Quote

Particle vs wave is not a property that can be entangled. They are not quantum states.

 

I disagree, the conclusion of the quantum eraser experiment done in 1999 is that it is knowledge of the path that changes the distribution pattern on both sides of the entangled pairs.

 

When the particles hit either D3 or D4 they create a dual distribution with D0 due to the fact that the path is known.

 

When the particles hit either D1 or D2 they create an interference pattern with D0 due to the fact that the path is not known.

 

Edited February 2, 2018 by TakenItSeriously

[swansont]

24 minutes ago, TakenItSeriously said:

What kind of arguement is that? I never said anything about the geometries of the dual slits. It’s assumed that they are the proper size in this thought experiment.

 

You have to show you are not assuming contradictory things. In order to have interference the beam has to hit both slits. And yet you want separation, so you know which slit it went through.

Quote

 

I disagree, the conclusion of the quantum eraser experiment done in 1999 is that it is knowledge of the path that changes the distribution pattern on both sides of the entangled pairs.

When the particles hit either D3 or D4 they create a dual distribution with D0 due to the fact that the path is known

When the particles hit either D1 or D2 they create an interference pattern with D0 due to the fact that the path is not known.

 

The path is not going through slits. You have an interferometer; you get interference because you bring the two beams together, even though they travel a well-separated path in the interim. If there is only one beam path, there is no interference.

You are understanding the words but apparently not the underlying physics.  

[TakenItSeriously]

19 minutes ago, swansont said:

You have to show you are not assuming contradictory things. In order to have interference the beam has to hit both slits. And yet you want separation, so you know which slit it went through.

For the QT, its the simplest possible setup where we are essentially running two dual slit experiments back to back with a shared entangled source. So the setup should be trivial. If its about aligning the slits to the beams properly, since they are beams I would imagine the slits would be moved infront of the beams until they produced the interference pattern on both ends as preperations.

19 minutes ago, swansont said:

The path is not going through slits. You have an interferometer; you get interference because you bring the two beams together, even though they travel a well-separated path in the interim. If there is only one beam path, there is no interference.

You are understanding the words but apparently not the underlying physics.  

Hmm, I think I am correlating the experiments correctly. With D3 & D4 they are only getting particles from one slit each, thats true. But thats the assumption with copenhegan interpretation, when observed its assumed the photons when slowed down to one photon at a time only goes through one slit at a time, not both.

With D1 & D2, they are probably setup to make sure the any Δd = nλ such that the wave is always in phase, so in both cases, they are reading patterns from a superposition of both slits.

[swansont]

9 minutes ago, TakenItSeriously said:

 Hmm, I think I am correlating the experiments correctly. With D3 & D4 they are only getting particles from one slit each, thats true. But thats the assumption with copenhegan interpretation, when observed its assumed the photons when slowed down to one photon at a time only goes through one slit at a time, not both.

With D1 & D2, they are probably setup to make sure the any Δd = nλ such that the wave is always in phase, so in both cases, they are reading patterns from a superposition of both slits.

There are no slits in the setup. The beam separation is from beam splitters (labeled as BS) and interference because of beam path overlap. 

[TakenItSeriously]

3 minutes ago, swansont said:

There are no slits in the setup. The beam separation is from beam splitters (labeled as BS) and interference because of beam path overlap. 

Look again, its not obvious, but the blue is one slit and the red is the other slit

[swansont]

1 hour ago, TakenItSeriously said:

Look again, its not obvious, but the blue is one slit and the red is the other slit

I see beam splitters (BS), Mirrors (M), prisms, detectors (D) and a lens.

The only thing passing as a slit is the mask that generates the two beams for the entangled pairs, i.e. before there is any entanglement.

[TakenItSeriously]

On 2/2/2018 at 9:32 AM, swansont said:

I see beam splitters (BS), Mirrors (M), prisms, detectors (D) and a lens.

The only thing passing as a slit is the mask that generates the two beams for the entangled pairs, i.e. before there is any entanglement.

Sorry for the late reply. I’ve been busy moving.

The dual slit isn’t labeled and is the first component that I point out below:

[swansont]

Yes, as I said, the mask that make the beams before there is any entanglement. You need two to have entangled photons.

[TakenItSeriously]

1 hour ago, swansont said:

Yes, as I said, the mask that make the beams before there is any entanglement. You need two to have entangled photons.

You have dual slits first and then whatever comes out of either (or both) slits are split into entangled streams, then the Quantum eraser shows that even a delayed observation of which slit a particle passes through will determine the pattern even after the fact when the pattern is recorded before the path is or is not detected, which is why the quantum eraser is the weirdest result in QM.

[swansont]

 How does this make particle or wave a quantum state?

IOW, what component of a wave function delineates particle or wave?

[TakenItSeriously]

4 hours ago, swansont said:

 How does this make particle or wave a quantum state?

IOW, what component of a wave function delineates particle or wave?

It’s a very confusing setup and I must admit it took me a while to figure it out myself.

It basically comes down to the particle streams are divided into entangled streams after the slits. One entangled stream always hits D0 and reveals either a dual distribution or an interference pattern. The other stream may strike one of four detectors after going through a series of splitters that will randomly determine the path of the particle.

if the entangled particle hits detector D3 then we know the origional, unentangled particle went through the bottom or blue slit, or if it strikes decector D4, then we know it went through the top or red slit. Therefore, when either of those detectors are hit, their entangled partner particles at D0 exhibit a dual distribution pattern, even though the particles strike D0 before hitting any splitters that randomly determine the path of the particle!

When they strike either D1 or D2, there is no way to tell which slit they traveled through, therefore they exhibit wave interference patterns at D0.

Weird right?

Edited March 12, 2018 by TakenItSeriously

[swansont]

Yes, it's weird but completely beside the point. The particle or wave nature is not what is entangled. "Which path" information is not a quantum state; it's an external influence.

[TakenItSeriously]

9 minutes ago, swansont said:

Yes, it's weird but completely beside the point. The particle or wave nature is not what is entangled. "Which path" information is not a quantum state; it's an external influence.

The particle or wave nature is what’s recorded at detector DO and is correlated through their entanglement to the path information at detectors D1-D4.

Edited March 12, 2018 by TakenItSeriously

[swansont]

1 minute ago, TakenItSeriously said:

The particle or wave nature is what’s recorded at detector DO and is correlated through their entanglement to the path information at detectors D1-D4.

That doesn't make it a quantum state. 

[TakenItSeriously]

2 minutes ago, swansont said:

That doesn't make it a quantum state. 

Ok, so what is your definition of a quantum state?

[Rob McEachern]

On 2/2/2018 at 6:58 AM, TakenItSeriously said:

I never said anything about the geometries of the dual slits.

That is the problem. The so-called interference pattern is a property (specifically, the power spectrum of the Fourier Transform of the geometry) of the geometry of the slits. It has little to do with the nature of anything passing through the slits; it is pure math. See: http://www.thefouriertransform.com/applications/diffraction3.php

If you change the geometry of the slits, for example by having the slit intensity profile be a Gaussian function of position, rather than a rectangular one, then the pattern will change. All these patterns are superpositions of the Fourier basis functions and thus "interference" patterns, but the "side-lobes" may or may not appear, depending on the geometry of the slits; specifically how abruptly the intensity function changes from 0 to 1.

In the physical experiments, the things passing through the slits merely act as carriers, that are spatially modulated by the slit geometry. But it is that geometry, not some property of the carrier, that determines the pattern - as the computation of the geometry's Fourier Transform demonstrates.

[Strange]

I can see a couple of reasons why this won't work as a communications mechanism.

The main one is, I think, because of a misunderstanding of how the experiment works. I have not fully understood what TakenItSeriously is trying to achieve but this seems to be based on the idea that the remote person could make the interference pattern appear of disappear by choosing whether to make an observation or not. (Please correct me if I am wrong.)

The trouble is, that is not how the experiment works. You need to correlate the photons detected at D1 to D4 with those detected at D0. When you do that, you find that the photons at D0 that correlate with D3 or D4 do not form an interference pattern, while those that correlate with detections at D1 or D2 do form an interference pattern. But, to determine this, you need access to the information from all detectors which needs a separate communication path that can only take place at light speed. So you might as well communicate normally.

 

[TakenItSeriously]

53 minutes ago, Rob McEachern said:

That is the problem. The so-called interference pattern is a property (specifically, the power spectrum of the Fourier Transform of the geometry) of the geometry of the slits. It has little to do with the nature of anything passing through the slits; it is pure math. See: http://www.thefouriertransform.com/applications/diffraction3.php

If you change the geometry of the slits, for example by having the slit intensity profile be a Gaussian function of position, rather than a rectangular one, then the pattern will change. All these patterns are superpositions of the Fourier basis functions and thus "interference" patterns, but the "side-lobes" may or may not appear, depending on the geometry of the slits; specifically how abruptly the intensity function changes from 0 to 1.

In the physical experiments, the things passing through the slits merely act as carriers, that are spatially modulated by the slit geometry. But it is that geometry, not some property of the carrier, that determines the pattern - as the computation of the geometry's Fourier Transform demonstrates.

If you want to argue against the Copenhagen Interpretation of QM to which I am simply referring to. Don’t take it up with me.

49 minutes ago, Strange said:

I can see a couple of reasons why this won't work as a communications mechanism.

The main one is, I think, because of a misunderstanding of how the experiment works. I have not fully understood what TakenItSeriously is trying to achieve but this seems to be based on the idea that the remote person could make the interference pattern appear of disappear by choosing whether to make an observation or not. (Please correct me if I am wrong.)

The trouble is, that is not how the experiment works. You need to correlate the photons detected at D1 to D4 with those detected at D0. When you do that, you find that the photons at D0 that correlate with D3 or D4 do not form an interference pattern, while those that correlate with detections at D1 or D2 do form an interference pattern. But, to determine this, you need access to the information from all detectors which needs a separate communication path that can only take place at light speed. So you might as well communicate normally.

 

I assume the data is digitally recorded and correlated and observed after an appropriate statistical sample size has been collected. Then the patterns are determined by the filtered data. I dont have access to the origional papers, only the articles or videos that described the experiment, but I assume that it has been well documented.

Edited March 12, 2018 by TakenItSeriously

[Strange]

6 minutes ago, TakenItSeriously said:

I assume the data is digitally recorded and correlated and observed after an appropriate statistical sample size has been collected. Then the patterns are determined by the filtered data. I dont have access to the origional papers, only the articles or videos that described the experiment.

Doesn't make much difference how or when the data is collected and correlated. There is still at least a light speed delay involved so you can't transfer information faster than light (if that was the intention).

[Rob McEachern]

8 minutes ago, TakenItSeriously said:

If you want to argue against the Copenhagen Interpretation of QM to which I am simply referring to

My point has little to do with the Copenhagen interpretation. The Copenhagen interpretation merely says that, physical systems generally do not have definite properties prior to being measured; thus, if the geometry can be changed (as by closing or opening a slit) immediately before a measurement is made, then there is no way to predict what the measurement will be, unless you can also predict when and what changes in geometry will occur.

[TakenItSeriously]

5 minutes ago, Strange said:

Doesn't make much difference how or when the data is collected and correlated. There is still at least a light speed delay involved so you can't transfer information faster than light (if that was the intention).

Well, again, I think you should take your arguements up with the origionators of the experiment which was done in the 90’s by Yoon-Ho Kim, R.Yu, S.P. Shih and Marlan O. Scully because that was their conclusion.

 

[Strange]

2 minutes ago, TakenItSeriously said:

Well, again, I think you should take your arguements up with the origionators of the experiment which was done in the 90’s by Yoon-Ho Kim, R.Yu, S.P. Shih and Marlan O. Scully because that was their conclusion.

I am not contradicting anything in the experiment or conclusions. Just pointing out that you can't use it for faster than light communication (if that is your intention).

And if you are saying that they concluded it could be used for faster than light communication then you are completely wrong.

[swansont]

1 hour ago, TakenItSeriously said:

Ok, so what is your definition of a quantum state?

Eigenstates of the wave equation solution would be quantum states.  Such as energy or angular momentum. There should be an operator which returns a value for the state variable, like the Hamiltonian gives you the energy.

 

[TakenItSeriously]

5 minutes ago, Rob McEachern said:

My point has little to do with the Copenhagen interpretation. The Copenhagen interpretation merely says that, physical systems generally do not have definite properties prior to being measured; thus, if the geometry can be changed (as by closing or opening a slit) immediately before a measurement is made, then there is no way to predict what the measurement will be, unless you can also predict when and what changes in geometry will occur.

Of course it has to do with the Copenhagen Interpretation because that interpretation is largely based upon the Dual Slit experiment and your arguement atttacks the conclusions from that experiment.