LHV simulation for bell setup based on photon bunching

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Discussion Overview

The discussion revolves around the implications of photon bunching in the context of Bell-type experiments, particularly focusing on local hidden variable (LHV) theories and the behavior of coincidence circuitry during simultaneous horizontal/vertical (H/V) measurements. Participants explore the historical context of these experiments, critique specific studies, and propose models that incorporate photon bunching as a factor influencing the results.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Exploratory

Main Points Raised

  • One participant suggests that the coincidence circuitry in Bell experiments may inadequately address simultaneous H/V measurements, raising concerns about the validity of results due to photon bunching.
  • Another participant questions the relevance of photon bunching in the context of M.A. Rowe's experiment and other three-particle GHZ experiments, implying that results could be consistent without it.
  • A critique of Rowe's experiment is presented, arguing that it fails to maintain the independence of measurements at both arms, which is fundamental to Bell testing.
  • Some participants express skepticism about the rigor of Rowe's experiment, suggesting that it assumes conditions that Bell experiments are designed to test, thus undermining its conclusions.
  • There is a call for more thorough analysis of photon bunching in existing literature, particularly in relation to GHZ and Kochen-Specker experiments, with a suggestion that such analyses are currently lacking.
  • One participant posits that the absence of photon bunching is a simplifying assumption in quantum mechanics, and that photon bunching may be more prevalent than previously acknowledged.

Areas of Agreement / Disagreement

Participants express differing views on the implications of photon bunching in Bell experiments, with no consensus reached on the validity of Rowe's experiment or the necessity of addressing photon bunching in theoretical models.

Contextual Notes

Participants note that the critique of Rowe's experiment relies on interpretations of its methodology and assumptions, highlighting potential limitations in the experimental design and the need for further investigation into photon bunching effects.

vzn
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hi all, I return to post after about a year.

one of the acknowledged loopholes in the bell experiments
is how the coincidence circuitry behaves under what might
be called "simultaneous H/V measurements" where H/V represent
horizontal/vertical polarized photons at one arm. basically, if you
have truly independent H/V detectors at each arm, you will measure
simultaneous H/V events at one arm. how will the coincidence circuitry
handle them? the naive approach is to just include them in the
coincidence counts without any filtering.

this is not an academic exercise, simultaneous H/V events at one
arm are an actually measured phenomenon that goes under the
name Hanbury-Brown/Twiss effect (measured by them) or also
(as I understand it) "photon bunching".

for a long time I wondered if one could construct an LHV (local hidden variable) theory for spin 1/2 particles & the EPRB setup based on this known loophole of photon bunching at one arm. it is certainly the case that almost none of the historical experiments directly address the possibility of photon bunching. [technically, the issue is handled in the coincidence circuitry, but none of the authors address it in their papers, including the classic Aspect experiments & many other bell type experiments]

recently I managed to do just that, ie put together an LHV theory for the bell-type experimental setup. it uses photon bunching at each arm to violate the nonlocality measurement even though the mechanism is strictly local. all the experimental measurements match up, ie the sinusoidal variation in coincidences, the correlation parameter, rotational invariance of total coincidences, etcetera.

here is a writeup of the code, the code, and numerical results of a run. the code is basically a monte carlo simulation. I believe this simulation violates the bell S locality parameter, although I have still yet to compute it.

http://tech.groups.yahoo.com/group/qm2/message/10215
http://tech.groups.yahoo.com/group/qm2/message/10216
http://tech.groups.yahoo.com/group/qm2/message/10217

I would be interested to correspond with anyone about the model, esp on the yahoogroup on QM foundations I founded/moderate

http://groups.yahoo.com/group/qm2/

there are some papers out there in the literature that suggest that photon bunching could be involved/implicated in bell-type experiments & an explanation for the supposed observations of nonlocality. I will dig them up if there is some serious interest.

I was also influenced by "nightlight" who posted some deep (and in my view compelling) analysis of photon bunching which is measured in "photon anticorrelation" experiments

http://groups.google.com/group/sci.physics.research/msg/f6a06bd01f0a7545
 
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Where are the "photon bunching" out of M.A. Rowe's experiment? If you argue that it is a different loophole, this means that even without any such photon bunching, you STILL get the identical result.

Or what about the 3-particle GHZ experiments? Where are the photon bunching there? And how do you account for the all-or-nothing-type Kochen-Specker experiment?

Zz.
 
alas the rowe experiment is quite an admirable and highly sophisticated
experimental tour de force but from the pt of view of bell testing rigor, quite lackadaisical and flawed. if you read the paper carefully and ignore the [somewhat misleading] diagram, you will realize that they used a single laser to illuminate both ions, and a single detector to measure their excitation.

but in the bell experiment, the very basic spirit is that measurements at both arms are independent! the rowe arrangement is so far from this as to be almost laughable. if you read the paper, they basically assume the very conditions that a bell experiment is designed to test. there is a line that reads almost, "assuming that QM is valid, we can make the following simplification in the setup..." and at which point they eliminate independent measurements at both arms. how bogus.

if rowe et al had used two lasers & two detectors, I would be far more laudatory of their experiment. imho if they hadnt billed it all as a test of bells thm, and more as a sophisticated measurement of qm properties of ions, I would have no objections. an obvious followup experiment, but rowe et al apparently have no further funding or interest in the subject. similar to the style of most researchers-- once they have done their one or two experiments to measure the cursory nonlocality violation, they lose all further interest and dismantle the hardware for something else.

re: GHZ/Kochen Specker. has anyone done these experiments yet? again you can see that theoretically there is no analysis of the concept of photon bunching or how to detect it or rule it out in the papers on the subject.

more specific/detailed critique on rowe et al here

http://tech.groups.yahoo.com/group/qm2/message/9730

I would say, increasingly it seems to me that QM is based on the simplifying assumption of absence of photon bunching in detectors. it seems that [from studying the experimental record] absence of photon bunching is a very difficult and contrived experimental and physical situation, however. in other words, I think photon bunching is quite widespread.
 
vzn said:
alas the rowe experiment is quite an admirable and highly sophisticated
experimental tour de force but from the pt of view of bell testing rigor, quite lackadaisical and flawed. if you read the paper carefully and ignore the [somewhat misleading] diagram, you will realize that they used a single laser to illuminate both ions, and a single detector to measure their excitation.

but in the bell experiment, the very basic spirit is that measurements at both arms are independent! the rowe arrangement is so far from this as to be almost laughable. if you read the paper, they basically assume the very conditions that a bell experiment is designed to test. there is a line that reads almost, "assuming that QM is valid, we can make the following simplification in the setup..." and at which point they eliminate independent measurements at both arms. how bogus.

if rowe et al had used two lasers & two detectors, I would be far more laudatory of their experiment. imho if they hadnt billed it all as a test of bells thm, and more as a sophisticated measurement of qm properties of ions, I would have no objections. an obvious followup experiment, but rowe et al apparently have no further funding or interest in the subject. similar to the style of most researchers-- once they have done their one or two experiments to measure the cursory nonlocality violation, they lose all further interest and dismantle the hardware for something else.

Then may I suggest you write a rebuttal to the Rowe et al. paper using this point. When it gets published, then we can all pay closer attention to your point. Last time I checked, no one challenged its conclusion nor any parts of its result. Why don't you?

re: GHZ/Kochen Specker. has anyone done these experiments yet? again you can see that theoretically there is no analysis of the concept of photon bunching or how to detect it or rule it out in the papers on the subject.

Yes, it HAS been done. Search PRL.


Sorry, but critique on some webpage is a dime a dozen, something that you already know. Someone could easily go into some forum and critique YOUR work, be it valid or not. This is not how physics is done, luckily.

I would say, increasingly it seems to me that QM is based on the simplifying assumption of absence of photon bunching in detectors. it seems that [from studying the experimental record] absence of photon bunching is a very difficult and contrived experimental and physical situation, however. in other words, I think photon bunching is quite widespread.

Have you TRIED doing any of the experiments? Or are you simply making "theoretical" comments on the nature of the experiment without having any first hand experience of doing it? How does one "study" experimental records? And don't you think that, while you're criticizing QM's "simplifying assumption", that you yourself have made a MAJOR assumption of this "photon bunching" with zero experimental backing? The same criticism can also be used towards what you just proposed, can it not?

I would also remind you, since you already know this from your snide comment about our IR forum policy, that this is definitely a personal theory and therefore, can only be done in the IR forum. Therefore, this discussion should be done there.

Zz.
 
hi zapperz. actually I do have a very intense desire to do a bell-type
experiment, and have read some of the excellent recent papers that are coming out of two almost-undergraduate physics laboratories. I've investigated some of the costs involved. have you done a bell experiment?

I do hope to get my hands on a bell experiment setup someday, possibly thru a local university. maybe in another half decade the technology will "trickle down" as they say about economics.

unfortunately the financial prerequisites for doing a bell type experiment are extreme. the aspect experiments I would estimate cost in the tens of thousands of dollars. recent technology with parametric down conversion brings the experiments down in price & looks very promising but are still significantly outside the realm of amateur testing.

re snide comment on forum policy, not sure what you are referring to. I regard physicsforums as a valuable place to post & value its many highly qualified moderators including yourself.

re the "independent research forum" on physics forums. imho its basically just a 3rd class thread ghetto. its moderator has posted a msg saying that he is busy with other projects & that's why the approved dialog is moving so slow. imho from a cursory review the policy is not actually designed to actively cultivate new theories, but in fact in applying the most friction possible in restricting them and shooting them down.

ZapperZ said:
Have you TRIED doing any of the experiments? Or are you simply making "theoretical" comments on the nature of the experiment without having any first hand experience of doing it? How does one "study" experimental records? And don't you think that, while you're criticizing QM's "simplifying assumption", that you yourself have made a MAJOR assumption of this "photon bunching" with zero experimental backing? The same criticism can also be used towards what you just proposed, can it not?

I would also remind you, since you already know this from your snide comment about our IR forum policy, that this is definitely a personal theory and therefore, can only be done in the IR forum. Therefore, this discussion should be done there.

Zz.
 

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