Bell's theorem and Harrison's (2006) inequality

[Farsight]

Thanks for that link, DrChinese.

 

[Careful]

***
Detector manufacturers use entangled photons as a technique to calibrate their detectors to an extremely high rate of accuracy. I don't have the figures for a specific manufacturer in front of me, but it is high and addresses your question exactly: a detection matches one photon, no detection matches no photon. The basic concept can be seen in studies like the following: ****

No, no, detection efficiency depends on the frequency of light, distance to the source and so on... Sudarsan and Glauber have studied this in the sixties, you cannot obtain (even in QFT) a genuine violation of the Bell inequalities with optical light (this is also a point Santos makes) - so your manufacturer probably has some more detailed information in small print in the booklet of the apparatus. Now, for solid particles (like electrons or kaons), it appears to me you can make probability of detection extremely high (for example by bombarding the electrons with high frequency photons) - with only a neglegible dependency upon distance (but please go ahead and tell us a better way of doing it). So, I have read that some 11 years ago a conclusive Bell test with Kaons was devised (and traditional realists agreed upon the conclusive nature of the latter) - you can read that in Franco Selleri's book ; hum, where can we read the test results ?

Could I ask you why you believe the dark current (or dark count) to be the only parameter which has something to do with detector efficiency ? Dark current is just the internal thermal current of electrons in the apparatus under assumption of absence of external fields. This is what you substract from the received signal, but that does not imply automatically that the received signal is what you get from the source. I guess the dark current could interfere with the received signal so that some distortion of the latter occurs (although it could very well average out in which case dark current would be irrelevant - could someone comment on this ?), but that does not fix your efficiency. Moreover it is not so clear what this has to do with the zero point field in SED (the latter would only produce quantum corrections to the dark current I presume), there the zero point field is non thermal and has no observable effects (it is believed to provide atomic stability of course) unless one has different boundary conditions for the electromagnetic field or some particle is accelerated through it (like in the Unruh effect). This is for example how they can explain the Casimir Polder effect and how a zero point field can influence the dynamics of interacting fields (detection process).

Moreover, if you use presumed sources of ``entangled photons'' as a way to calibrate your detectors, it becomes rather impossible (from a logical point of view) to consider the possibility that entanglement might not exist in the first place, no ? :-)

Careful

 

[QuantunEnigma]

Re-read the Guidelines that you have agreed to. Personal, unverified theories and ideas are NOT allowed. If you have a personal theory to push, do so in the IR forum. You have been told this before, and I very seldom repeat what has been said.

Furthermore, citation to some website does NOT strengthen your case! So stop doing that. This is not how science, and especially physics, is done. If you think you have a valid idea, cite a respected peer-reviewed journal.

I expect that this is the last time I have to explain this.

Zz.

QUOTE OF ZZ ACTION
The secret site is the one that you and i are monitoring, that is all. The one that cannot be mentioned like this [SPAM link removed - the NEXT time I have to do this, you're gone! - Zz.] because I do not know how to make it a hidden legal link to show what we are talking about. If you would show me how please I would edit this posting and leave in peace. END

Sir, I am writing to ask please correct the words of your deletion. Unless I am mistaken. The site IS NOT A SPAM SITE because not like Physics Forums it has no advertisements and I can see no reward for clicks or views. "It is a free public service science blog with references to 100 peer reviewed articles and it is based on peer reviewed and published theory that has not been changed or refuted or modified."

You are the one who can delete but in fairness your deletion should not distort facts unless i do not understand what is a SPAM SITE please. Can you say? Site deleted or personal science blog deleted.

Also, because the site is edited every day I think it cannot work under a loss of editorial freedom which your referral appears to require. The author thinks that.

I am note arguing with you right to delete, only that be fair like a scientist and present facts please. Unless i am wrong

 

[ZapperZ]

QUOTE OF ZZ ACTION
The secret site is the one that you and i are monitoring, that is all. The one that cannot be mentioned like this [SPAM link removed - the NEXT time I have to do this, you're gone! - Zz.] because I do not know how to make it a hidden legal link to show what we are talking about. If you would show me how please I would edit this posting and leave in peace. END

Sir, I am writing to ask please correct the words of your deletion. Unless I am mistaken. The site IS NOT A SPAM SITE because not like Physics Forums it has no advertisements and I can see no reward for clicks or views. "It is a free public service science blog with references to 100 peer reviewed articles and it is based on peer reviewed and published theory that has not been changed or refuted or modified."

You are the one who can delete but in fairness your deletion should not distort facts unless i do not understand what is a SPAM SITE please. Can you say? Site deleted or personal science blog deleted.

Also, because the site is edited every day I think it cannot work under a loss of editorial freedom which your referral appears to require. The author thinks that.

I am note arguing with you right to delete, only that be fair like a scientist and present facts please. Unless i am wrong

Then cite the exact paper that support your position and not simply a whole webpage! That webpage is espousing a personal theory that is not back by conventional physics, regardless on whether it contains published papers or not. You have been told about our rules against speculative theories. Take it, or leave.

Zz.

P.S. I'll call it crackpot spam if that makes you feel any better.

 

[DrChinese]

1. Could I ask you why you believe the dark current (or dark count) to be the only parameter which has something to do with detector efficiency ? Dark current is just the internal thermal current of electrons in the apparatus under assumption of absence of external fields. This is what you substract from the received signal, but that does not imply automatically that the received signal is what you get from the source. I guess the dark current could interfere with the received signal so that some distortion of the latter occurs (although it could very well average out in which case dark current would be irrelevant - could someone comment on this ?), but that does not fix your efficiency. Moreover it is not so clear what this has to do with the zero point field in SED (the latter would only produce quantum corrections to the dark current I presume), there the zero point field is non thermal and has no observable effects (it is believed to provide atomic stability of course) unless one has different boundary conditions for the electromagnetic field or some particle is accelerated through it (like in the Unruh effect). This is for example how they can explain the Casimir Polder effect and how a zero point field can influence the dynamics of interacting fields (detection process).

2. Moreover, if you use presumed sources of ``entangled photons'' as a way to calibrate your detectors, it becomes rather impossible (from a logical point of view) to consider the possibility that entanglement might not exist in the first place, no ? :-)

Careful

1. I didn't mean to imply that the detector dark count is the only variable involved. It's not. There are plenty of experimental setup issues that affect total efficiency, such as beam splitters, filters and polarizers. I was really trying to focus on the detector itself as a source for false readings.

2. Yes, this does make logical sense as a way to calibrate. It doesn't really matter if you call it entanglement or not, there is an effect that is readily measured and it is really undeniable. There are virtually no cases of coincidences when the PDC source is turned off (i.e. no coincidences due to noise). Once the PDC source is turned on, there are virtually no cases of double detections on one side (i.e. 3 fold coincidences). I don't know the exact rate of 1-fold coincidences (i.e. detection of only one of a pair), so I will see if I can drill into that stat.

 

[Careful]

**1. I didn't mean to imply that the detector dark count is the only variable involved. It's not. There are plenty of experimental setup issues that affect total efficiency, such as beam splitters, filters and polarizers. I was really trying to focus on the detector itself as a source for false readings. **

Right ! Now, you seem to be stuck with the Von Neumann measurement postulate (or consciousness) and regard photons as non local plane waves. You cannot do that : (a) it makes no sense, you completely deny local physics (b) such waves are not normalizable, hence you cannot even apply the Von Neumann postulate here. Rather, you have to make a local model of detection (remember: the dynamics of QFT is local) and apply the reduction at a later stage (which gives you genuinely different results !). Now, localized wave packages (with characteristic wave length lambda) will spread around and local quantities (probability density) will decrease, affecting the probability of detection...

**
2. Yes, this does make logical sense as a way to calibrate. It doesn't really matter if you call it entanglement or not, there is an effect that is readily measured and it is really undeniable. There are virtually no cases of coincidences when the PDC source is turned off (i.e. no coincidences due to noise). **

Again, you ignore the possibility that when the source is turned on, there is an enhancement of such coincidences (as you would expect from local physics). I guess you can expect a delay between the arrival time of the ``created pair'' and arrival time of the original one. Moreover, in experiment, not all ``photons'' will have the same spatial density and many of them can get lost (as is the case in the low frequency range).

Now, you seem to be confused by my position. I am a local realist and I could really offer you good reasons why a non local world view is nonsensical (actually it is pretty easy to give a crazy local (in the strict sense!) theory behind the Von Neumann measurement postulate if you are creative enough) but I prefer to keep an open mind. As far as I am aware, it is possible to give a local theory of EPR with a local measurement dynamics (and without denying reality) - see my allusion to negative probabilities (you might be interested to read about this). However, on the other side, it is still possible to claim that a ``less quantal'' point of view is possible, see SED or better Barut self field. So, one would better do the experiment with neutral Kaons, or do experiments in which local realist predictions (deviating from the QM ones) can be checked. This would settle the matter more easily. But in ANY case (there is in the worst case a lack of creativity), there is no obvious problem with local realism as far as I am concerned, only some types of ``naive'' local hidden variable theories (the ones assuming screening off *and* dichotomic outcomes) could be killed off, but where remains the conclusive series of experiments ?

Careful

 

[DrChinese]

Now, you seem to be confused by my position. I am a local realist and I could really offer you good reasons why a non local world view is nonsensical (actually it is pretty easy to give a crazy local (in the strict sense!) theory behind the Von Neumann measurement postulate if you are creative enough) but I prefer to keep an open mind. As far as I am aware, it is possible to give a local theory of EPR with a local measurement dynamics (and without denying reality) - see my allusion to negative probabilities (you might be interested to read about this).

Sure, I am confused any time a local realist tells me an experiment should not be considered because non-local influences were not adjusted for. If you believe there is a local model which differs from Malus in its predictions, then the thing I am immediately interested in is: what are the specific values that are really present?

Sure, I am interested in negative probabilities because I think any local realistic model will yield probabilities greater than 1 or less than zero somewhere along the line. The reason I "know" this is because of Bell's discovery.

 

[ttn]

I am interested in negative probabilities because I think any local realistic model will yield probabilities greater than 1 or less than zero somewhere along the line. The reason I "know" this is because of Bell's discovery.

Could you give an example of a theory which is "local" but not "realistic" and which agrees with the QM predictions here? Or more basically, do you think that such a theory is (in light of Bell's discovery) possible?

If not, why use the cumbersome and vague phrase "local realism" when, evidently, you just mean "local"?

 

[DrChinese]

Could you give an example of a theory which is "local" but not "realistic" and which agrees with the QM predictions here? Or more basically, do you think that such a theory is (in light of Bell's discovery) possible?

If not, why use the cumbersome and vague phrase "local realism" when, evidently, you just mean "local"?

1. If you accept, as I do, that the Heisenberg Uncertainty Principle is a "complete" description of reality, then I believe you have a non-realistic position. So any interpretation of orthodox QM that matches would be such a theory.

2. I cannot avoid the phrase "local realistic" in my discussion, because this is generally accepted from Bell's work. If you believe in locality, I believe you must therefore reject realism. I also believe that it *might* be possible to construct a non-local theory which is realistic, but I am not sure about this.

 

[wm]

drChinese's "negative probabilities" rebutted?

Dear David, a rebuttal of your ''negative probability case" (from your website) may be found at [link deleted]

I would welcome any comments, especially any which make your case clearer to the general reader. Of course, if I've mispresented it, please let me know that too.

wm

 

[wm]

Would a meeting of local realists fill a phone booth?

** I am a local realist and I could really offer you good reasons why a non local world view is nonsensical (actually it is pretty easy to give a crazy local (in the strict sense!) theory behind the Von Neumann measurement postulate if you are creative enough) but I prefer to keep an open mind. As far as I am aware, it is possible to give a local theory of EPR with a local measurement dynamics (and without denying reality) - see my allusion to negative probabilities (you might be interested to read about this). However, on the other side, it is still possible to claim that a ``less quantal'' point of view is possible, see SED or better Barut self field. So, one would better do the experiment with neutral Kaons, or do experiments in which local realist predictions (deviating from the QM ones) can be checked. This would settle the matter more easily. But in ANY case (there is in the worst case a lack of creativity), there is no obvious problem with local realism as far as I am concerned, only some types of ``naive'' local hidden variable theories (the ones assuming screening off *and* dichotomic outcomes) could be killed off, but where remains the conclusive series of experiments ?

Careful

I am a local realist too. However I see no need for a sound local realistic theory to predict results "deviating from QM ones". (Thus you may take it that I seek no loop-holes in QM experimental outcomes. QM is a great theory.) Rather, it is my view that QM is an abstract local realistic theory. That is, it's my view that QM is one level of abstraction removed from a wholly concrete local realistic theory.

Now the start of this thread related to Harrison's inequality. So, in support of my view, a draft rebuttal of Harrison's inequality may be found at [link deleted]. It is a draft only in the sense that I'd like David Harrison or BoTemp to check that it accurately presents their case.

wm

 

[ZapperZ]

Dear David, a rebuttal of your ''negative probability case" (from your website) may be found at [link deleted]

I would welcome any comments, especially any which make your case clearer to the general reader. Of course, if I've mispresented it, please let me know that too.

wm

Y'know, for some odd reason, my repeated warning for your personal work to be done in the IR forum seems to have fallen onto deaf ears. Obviously, you appear to think that this is a joke.

Thus, you leave me no choice with your continuing transgression of our guidelines. This thread is done.

Zz.