How would you overcome entrenched vested interests? For example:
RE: Editorial policy of Optics Letters
To: The Editor-in-Chief of Optics Letters
With reference to your message reproduced below, the expert’s comments dealing with the subject of quantum nonlocality are riddled with errors and omissions. The expert failed to mention that:
1. The commutator between any two Pauli spin operators results in the remaining third commutator. Its numerical evaluation depends on the wavefunction of the photonic system and is not state-independent as, surprisingly, claimed by your expert;
2. A growing body of published articles have disproved and rebutted the concept of quantum nonlocality - see the list of references we provided in our initial inquiry with your office. Your expert in quantum optics seems to be unaware of such developments which contain the answers to other errors in the expert’s statements. For example, an overlap between two states projected onto the measurement Hilbert space has nothing to do with two separate Hilbert spaces - see the first two references on our list in the initial inquiry.
3. The role played by the process of quantum Rayleigh scattering of photons is well documented, but your expert could not explain how a single photon can propagate in a straight-line in a dielectric medium.
Our question to you, in your capacity of Editor-in-Chief of Optics Letters, is:
1. Whether or not your editorial policy supports your expert’s position of stymying any debate on the subject of the non-existence of quantum nonlocality? , and
2. Could you also explain the reasons for your support of such a non-scientific methodology to suppress dissemination of knowledge?
Written on 21 February 2021
The following references unambiguously disprove and rebut the concept of quantum nonlocality, in general, and in the context of photonic systems, in particular:
1. Robert B. Griffiths, “Nonlocality claims are inconsistent with Hilbert-space quantum mechanics”, Phys. Rev. A 101, 022117 – Published 28 February 2020.
2. F. J. Tipler, "Quantum nonlocality does not exist", PNAS 111 (31), 11281-11286, August 5, 2014; https://doi.org/10.1073/pnas.1324238111.
3. A. Vatarescu, “The Scattering and Disappearance of Entangled Photons in a Homogeneous Dielectric Medium,” Rochester Conference on Coherence and Quantum Optics (CQO-11), doi.org/10.1364/CQO.2019.M5A.19.
4. S. Boughn, “Making Sense of Bell’s Theorem and Quantum Nonlocality”, Found. Phys., 47, 640-657 (2017).
5. A. Khrennikov, “Get Rid of Nonlocality from Quantum Physics “, Entropy 2019, 21, 806.
6. M. Kupczynski, “Closing the Door on Quantum Nonlocality “, Entropy 2018, 20, 877.
As a matter of fact, one single photon cannot propagate in a straight line in a dielectric medium because of the Rayleigh spontaneous emission or scattering. Only a group of photons can maintain a straight line of propagation as a photon absorbed by an electric dipole is recovered through Rayleigh stimulated emission induced by the other photons in the group.
It would be advisable to submit for publication to the journals that have published similar papers before. There's no point in submitting to a journal that hasn't published papers on this topic. All the published papers mentioned have appeared in other journals.
It's hard to complain about vested interests when it appears that papers on this topic have been published.
Thanks Stam Nicolis for your contribution.
There is a strong opposition from the long-time supporters of the concept of quantum nonlocality to having any rebuttal published by "legacy journals"". The article in the Physical Review A published in February 2020 was the first of its kind in that journal. And previous articles rebutting the concept of quantum nonlocality are never mentioned, let alone addressed, in repeated reviews on the subject, for the simple reason that the concept of quantum nonlocality cannot be defended physically.
As to Optics Letters, as a leading OSA journal, they have a section on Quantum Optics which includes the photonic systems used in the relevant experiments. They should inform their readers of any physically meaningful developments rather than providing misleading and incorrect reports in order to discourage submissions in the future, as do many editors whose vested interests of past contributions may become obsolete.
The main problem with "quantum nonlocality" is that every scientist of consequence knows that it is nothing but a catchy term. Quoting from memory:
"I always make it clear in my lectures that correlations may be instantaneous across space-like intervals both in quantum and classical mechanics, and that this does not constitute nonlocality in the true meaning of the word." (Stig Stenholm)
"When I write about nonlocality in my grant application, it is much more likely they give me money." (Dan Walls)
"If you are right, I must publish this in J Phys B, and I want PRL." (John Rarity)
No more comments.
L. I. Plimak,
Lev, what happens to you? Of course the quantum entanglements are nonlocal. Joint results obtained by Alice on particle A and Bob on particle B, depend on both the settings in Alice's lab and Bob's lab.
Worse than that, Alice and Bob can measure at different times. Therefore, it turns out that the joint measurements results depend on both present and future.
With kind regards
Sofia D. Wechsler
Dear Sofia,
You confuse measurement and inference. When Alice measures something, she can infer what Bob has measured. This inference is based on much more knowledge than just her own results, notably source properties and the lab design at Bob's. For instance, Alice implies that there was no power outage at Bob's. If you include all the information that Alice uses, explicit as well as implicit, and trace all causality chains, you find no paradoxes nor "nonlocality".
Actually, in Bell's argument, nonlocality was used as absurdum in the standard reductio-ad-absurdum argument. "If we assume hidden variables, we must also assume nonlocality. However, since we know very well that quantum theory is local and causal, this conclusion is absurd. Therefore quantum theory cannot be reduced to ANY kind of hidden-variable theory."
So much for quantum nonlocality.
L
Reply to S. D. Wechsler and L. I. Plimak,
From ref. 3 listed above for the discussion, for the single and independent photons created through quantum Rayleigh scattering in dielectric devices, one obtains the same correlation function. Therefore, the Bell-type inequalities can be violated locally. Thus, L. I. Plimak is correct in stating that "quantum theory is local and causal". But statistics can do anything as S. D. Wechsler says - one can measure at any time two different systems and compare the outcomes for correlations in a different measurement space.
Andre X Vatarescu
Drear Andre,
When I say "quantum theory", I mean quantum field theory in all its power. Unlike elementary QM, it handles quantum statistics in both senses of the term: fermions-vs-bosons and correlations.
L
L. I. Plimak
Lev, my friend, It's too late for me, after tens of years of dealing with the measurement problem, to do such childish confusions.
1. Alice can make no inference. Whatever she knows is the result of her measurement. She has no other knowledge, unless Bob conveys to her the data of his measurement, i.e. setting of his apparatus and result.
2. Note that you don't prove, in what you say, that QM is local. You only say (postulate) that, but do not prove. Please read Hardy's article, world-wide famous,
L. Hardy, “Quantum Mechanics, Local Realistic Theories, and Lorenz-Invariant Realistic Theories”, Phys. Rev. Lett. 68, no. 20, page 2981, (18 May 1992).
Bell's proof against locality has weak points. Hardy's proof is absolutely rigorous, as acknowledged by all the QM community. In base of his article there was a whole debate to which participated the greatest minds (who, unfortunately, are no more among us), as Unruh, Shimony, and others. People spent years in trying to find a flaw in that proof. None was found.
Hardy's article is long, but one has to read it attentively.
With kind regards,
Sofia
Reply to S. D. Wechsler in support of L. I. Plimak
On the first page of the article by L. Hardy mentioned by S. D. Wechsler, the following statement appears: "The gedanken experiment we are going to consider ...". That is, that article deals with speculative thoughts.
By contrast, experimental results by M. Ringbauer et al., ”Experimental test of nonlocal causality”, Science Advances, 2 (8), 10 Aug 2016, DOI: 10.1126/sciadv.1600162,
clearly finds experimental outcomes so that "A direct causal influence from one outcome to the other can therefore not explain quantum correlations.”
Additionally, two local measurements carried out at a distance from each other, with identical optical sources generating the same states of polarization and with randomly rotated polarization filters, will result in the same correlation function as for "entangled" photons (see ref 3. above for discussion) which, while generated together, propagate separately to distant detectors. For a quantum interaction to take place, as required by a wavefunction "collapse", a Hamiltonian of interaction is needed - so what is this Hamiltonian? And since the Hilbert spaces describing the states of the two separated photons are carried away from each other and no longer overlap, any element of the transition matrix will vanish - see the article by R. B. Griffiths on the above list.
The use of a global wavefunction which is time- and space- independent is the root cause of confusion because it can be applied to any quantum events regardless of their time and space of their existence. After all, the Schrodinger wave equation is space and time-dependent.
It is known that John Nash, the winner of the Nobel prize in the domain of the game theory, came in his youth to von Neumann with a proposal regarding quantum mechanics, to which von Neumann answered to Nash "Learn some physics !".
The same to those who propose that QM is local: "Learn about entanglements !"
One of the big differences between QM and the classical machanics is that two quantum particles may evolve with a common phase. This is the key of the phenomenon of entanglements and of the non-locality. The algebra of the joint phases may erase a certain combination of results of the two particles, or enhance its amplitude of probability, disregarding the distance between the particles, and even the difference in time between the measurements.
Reply to S. Webster,
As the two Hilbert spaces of the two photons move away from each other, how do they interact at the moment of detection? The integral will vanish.
You should spell out the Hamiltonian of interaction, rather than claiming that others had posited some nonlocal phase variations which in the context of a global wavefunction may bring about a quantum interference.
Measurements come before probabilities and measurements are localised in time and space.
Well, this is a fun discussion; and it echos one which I unexpectedly stumbled into recently. However, I think the disagreement here is in fact only between two different notions of what "non-locality" means; and not a disagreement about predictions of QM.
Perhaps each side should try to state (and deliberately without any reference to the other side of the argument) exactly what they do mean (or would mean) by something being non-local. I think this would be instructive.
Paul Kinsler
Dear Paul,
This discussion aside, all physicists of standing of which the talks I have listened to, and private discussions with whom I have had, over last 30 years, made an important reservation, that "quantum nonlocality" cannot be used to transfer information. In other words, "quantum nonlocality" does not imply any kind of action at a distance. Whether such phenomenon can be termed "nonlocality" is a matter of taste. Personally, I find this term utterly misleading.
Now, what term would be good? In classical mechanics, we have "propagation" and "statistics" (correlations). Propagation is subject to relativistic causality (retardation) laws, so that any phenomenon manifesting itself over space-like intervals may only be statistical. Can we extend the same dichotomy to QM? Indeed, in QED, this can be done in the language of phase-space path integrals. Technically, this is a marriage of the so-called real-time quantum field theory (Schwinger, Kubo, Keldysh) with the operator-ordering concepts of quantum optics (Feynman, Glauber, Sudarshan, Kelley-Kleiner, Klauder); it is all published stuff, and references are available on request. The said path integrals emulate the corresponding formulae of the classical stochastic electrodynamics, where the paths are causal (retarded) solutions to Maxwell's equations, while statistics is replaced by real, but, in general, non-positive, pseudo-statistics. This replacement of statistics by pseudo-statistics is the only quantum effect that may be observed macroscopically. In particular, all violations of Bell's inequalities using quantum states of light are due to the said replacement of statistics by pseudo-statistics. I emphasize that it is a proven theorem.
There is a strong indication that similar results may also be derived for fermions, but I would rather refrain from claiming them -- not to mention that fermionic (Grassmann) path integrals have no classical analogue.
Now, if anyone still believes that the term "quantum nonlocality" makes sense, he is welcome to use it. However, adding or implying the reservation that "quantum nonlocality" cannot be used to transfer information, and therefore is not nonlocality in the true meaning of the word, is a must. My preference is "nonlocal quantum correlations impossible in classical statistical mechanics".
To Paul Kinsler,
In quantum optics, the concept of quantum nonlocality would have one measurement of an entangled photon affect the outcome of a remote measurement of the other entangled photon. This is apparently used in some quantum applications but, physically, it requires sources for one single-photon per radiation mode which, allegedly, underpins the one- and two- photon remote interference with, respectively, one photodetector and two photodetectors. However, the probability amplitudes are calculated with a global wavefunction of an ensemble of measurements so that there is no time- or space- dependence, and each individual measurement would require two photons for an interference pattern.
Additionally, a single photon cannot propagate in a straight line inside dielectric devices and components because of the quantum Rayleigh scattering, so that the “entangled” photons are replaced by independent ones.
A scrutiny of the optical sources reveals that groups of identical photons are, in fact, emitted per radiation mode, making the miracles of quantum optics rather identical to "classical" interference. The spontaneously emitted photons from a nonlinear crystal cannot escape amplification despite the low levels of pump power, and a quantum dot placed inside a high Q-factor resonant cavity will operate as a poorly performing laser but, nevertheless, the single photon will be reflected and amplified before leaving the cavity.
L. I. Plimak
I very much agree with your position.
However, I think it is that some others see that a local measurement here changes a remote state; and see that change as a sign of a non-local "action", even though that change is not useful in any meaningful way.
IMO, this view is kind of a naive theorists view, in that it is one that they can write down from an imaginary all-seeing perspective, as their equations, which describe easily all parts of the system, can naturally can tell them about "remote" events as easily as "local" ones.
But of course what we really need to do is think about what a guy with a detector measures, and what inferences and actions they might take given some result. And if we look at things in that way instead, I think we are driven to the "cannot be used to transfer information" position, and so hopefully then question whether the apparent non-locality of the equations is any kind of physically meaningful non-locality.
Andre X Vatarescu :
Actually, going back to your original question, I think my preferred tactic in these cases is to at all cost avoid falling into a combative "me right/ you wrong" argument. Just add in a paragraph explaining your preferred meaning of (non)locality (e.g. as per L. I. Plimak above, and whatever references you like) and mentioning that other descriptions exist (the more relaxed one as I tried to outline above, presumably as per Sofia D. Wechsler might argue, with some references) . Then say e.g. "In this work we use the first definition" (maybe calling it a "stricter definition" would help). You've then acknowledged both sides, described both of them, and then chosen; which is a very reasonable way to proceed. And you hopefully haven't alienated those who - for whatever reason - prefer the looser usage; and maybe they'll even acknowledge some value in the stricter one.
Paul Kinsler
Just a funny thought, without really claiming anything.
Let us stay within QED. Phase-space path integrals I mentioned are subject to, firstly, the Heisenberg picture, secondly, to the closed-time-loop formalism, thirdly, to a particular representation of this formalism (response picture, see PRA 92, 022122 (2015) and references therein). In such an approach, things like evolving quantum states characteristic of the Schroedinger picture simply do not exist. Whether requirements of explicit locality and causality may be extended to them or not is not at all clear. It may therefore well be that in the semi-phenomenological approach to the measurement, based on "collapse" in the Schroedinger picture, a local measurement does change a remote state, but this change has no observable consequences (cf. "cannot be used to transfer information").
Once more, I do not make any formal claims, just thinking aloud.
In the QED domain entanglements don't hold anymore, because QED (as well as QFT) are for high energies. At such energies the number of particles is not fixed anymore. The simplest example, at high energies the spin of a quantum partice changes so that the spin singlet is distorted.
"Let's stay with the QED" means "let's exclude from our judgements the entanglements".
Unfortunately, it's exactly the entanglements which display nonlocal properties. So, can something be more trivial than eliminating the entanglements from the talk, the quantum nonlocality is eliminated?
Sofia D. Wechsler
Dear Sofia,
Quantum optics is quantum electrodynamics approximated for low energies. Glauber-Kelley-Kleiner's photodetection theory is formulated in quantum-field-theoretical terms, in the Heisenberg picture employing the operator of the electromagnetic field. With all respect, claiming that this theory does not cover entangled photons is ludicrous. Tell this to Alan Aspect or Roy Glauber and hear them laugh. If you think Roy got his Nobel prize for a theory not covering Bell violations, think again.
Sapienti sat.
Yours
Lev
L. I. Plimak
Lev, my friend, I learnt (tens of years ago) quantum optics, so, it's little chance that somebody explain me what it is. Quantum optics is what the name says, no more and no less, the optics of photons at the quantum level, i.e. considering individual photons and the relationship between them, as for instance bunching, degree of coherence of beams, etc. Of course I learnt the theory of detection of photons, but that is only one chapter in the quantum optics.
Also, you say
"claiming that this theory does not cover entangled photons is ludicrous. Tell this to Alan Aspect or Roy Glauber and hear them laugh. If you think Roy got his Nobel prize for a theory not covering Bell violations, think again."
Lev, ARE YOU A PHYSICIST? Physics goes with proofs!!! You cannot postulate things, you should prove! You said in another post, "let's stay with the QED". NO! We cannot. We would loose most of the entanglements, in particular the famous Hardy-type state, in base of which he proved that elements of reality don't exists. At high energies the number of particles is no more fixed, spin is altered, and other troubles. We NEED the low energy, i.e. non-relativistic domain. That means, we NEED the non-relativistic QM.
Did you hear of contextual experiments? They provide stronger evidence that QM is nonlocal, than statistical evidence as in the violation of the Bell-type inequalities.
As one that dealt with the fundaments of the QM for tens of years, I am telling you that the nonlocality of the QM in space is no mistery, it has a clear explanation. It is only the nonlocality in time that is not understood.
With kind regards and wishes of health,
Sofia
Dear Sofia,
Do you accept as a general principle that whatever contradicts relativity in a nonrelativistic approach is an artifact of this approach?
Cheers
Lev
To Paul Kinsler,
The attached manuscript which is still under consideration by Optics Letters should answer your request for details.
To l. I. Plimak,
You wrote: "If you think Roy got his Nobel prize for a theory not covering Bell violations, think again."
Actually, if one reads the references in the manuscript I attached to this reply, one will find out how Glauber got it badly wrong with the second-order coherence concept because the finite dimensions of the photonic field prevent any remote interaction between two photodetectors. The related experimental results produced by Mandel can be explained by taking into consideration all the physically present effects and interactions as pointed out in the manuscript.
For other readers of this discussion, a recent book titled " The Physical Reality of Applied Quantum Optics" may be of interest.
L. I. Plimak
What is the fact that you believe that contradicts relativity? Name it! I do not know what you talk about.
Whatever I see is that Andre has problems with the nonlocality. This is a property of the entanglements. It is indeed problematic but not vis-a-vis the relativity, only vs. causality, because in entanglements there is mutual interdependence between past and future events.
Best regards!
Sofia D. Wechsler
Dear Sofia,
No problem, I reformulate.
Do you accept as a general principle that whatever contradicts strict relativistic locality and causality in a nonrelativistic approach is an artifact of this approach?
Cheers
Lev
My dear Sofia D. Wechsler , and dear L. I. Plimak
I miss your discussions, I have affected by a coronavirus, but thank God I am now good, but I encountered very difficult days.
I think the nonlocality is self-evident in quantum mechanics.
In the double-slit experiment when the two slites are open then we have an interference pattern but when we have one slit open we don't have this pattern, how the particle knew that we opened the second slite to change its behavior?
So the behavior of the particle was affected by all the staff of the experiment, this is the nonlocality in a simple picture, as a formal proof we can read the Kochen-Specker theorem, in other words, the particle is affected by all fields that exist in the space of experiment, It does not matter how far it is from it.
With best regards.
To Sofia D. Wechsler,
A manuscript attached above - see 424376.pdf - to replies for Plimak and Kinsler rules out spatial quantum nonlocality.
Would you disagree?
I've just been reading this; I think the introductory part has a very nice summary:
Causal networks and freedom of choice in Bell's theorem
https://arxiv.org/abs/2105.05721
To Paul Kinsler,
That manuscript is still under negotiations with Optics Letter. The Introduction you like was slammed by a reviewer for exposing the one-sided presentation of the 2020 review paper of reference [1]. It's getting more and more challenging for the supporters of quantum nonlocality. Slowly but steadily, the non-existence of quantum nonlocality will prevail. Hopefully!
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