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Tuesday, December 18, 2018

The Core Assumption of Every Known Single-Photon Experiment is Wrong.

The Core Assumption of Every Known Single-Photon Experiment is Wrong.
Dr. Valentin Voroshilov
DOI: 10.13140/RG.2.2.25910.96329

Recent paper (R. Chaves, G. Barreto Lemos, J. Pienaar; 2018) describes “statistics generated … by a photon in the Mach-Zehnder interferometer” in “the Wheeler’s delayed-choice experiment”, or its modified version.
In the original thought experiment (J. A. Wheeler, 1978), a photon enters an interferometer at the location of a beam splitter BS1, and “the experimenter chooses whether or not to remove the beam splitter BS2 after a photon has entered a Mach- Zehnder interferometer (at BS1).”
(Figure is used with the permission of the publisher)
The authors “treat the photon in the Mach-Zehnder interferometer as a two-level quantum system”. The statistics is to be supplied using “photon counting … detector(s)”.
The authors offer a quote (H. Paul, 1982) “It is essential that a single photon source is used, such that both detectors never click simultaneously. This guarantees that each photon cannot be modeled as a classical wave that is quantized only at the detector”.
The discussion essentially revolves around different possible descriptions of a photon traveling along only one possible path, or (as a manifestation of its wave-like properties) along two paths at the same time.
A beam splitter is a device an interaction with which may open for a photon two possible paths to travel along. For the original or a modified experiment, all versions of reasoning about possible outcomes of an experiment are based on the assumption that the photon that eventually enters a detector is always the same photon that entered an interferometer (e.g. at beam splitter BS1)

If that's not a case, the whole experiment loses all the sense.
This assumption, however, is wrong.
A beam splitter is a macroscopic optical device which consists of a large number of atoms or molecules.
When a photon is encountering a device, it does not interact with the device as a whole, it only interacts with a specific atom. As the result of that interaction the photon can be absorbed or scattered. In the latter case, the photon may encounter another atom, and interact with it. There is always non-zero probability that the original photon will be absorbed by the device, and a photon leaving the device will be produced by an atom in the device. Hence, in the latter case, the device does not open for a photon two different paths; a photon does not take one path or another, or both. An original photon gets absorbed, disappears. But, as the result of complicated interactions inside a device, the device eventually (the process takes time) emits a new photon, which on its way to a detector may encounter another optical device, etc. 

It's like two twine magician brothers showing a trick; one brother enters a booth and as soon as he closes the door another brother opens a door of a second boot and gets out. It looks like a man instantly moved from one booth into another one. In reality, those are two different men tricking everybody.
Exactly same situation will be happening when a photon interacts with any optical device, including (but not limited) a fully reflective mirror, a lens, a prism, a polarizer, a fiber optical cable.
Under these circumstance, any statement about the fate of the original photon entering a detector is wrong, because there is always non-zero, and not accounted for, probability that the photon entering a detector is not the original one, but the one emitted by an optical device (at least one of several devices existing between the very first device and a detector).
An optical device, any optical device, simply cannot be used to make a definite (known) alternation (from a set of possible alternations) in the behavior of a photon entering that device, because there is always non-zero probability of the photon being absorbed.
The result of an action of an optical device on light i.e. (reflection, refraction, polarization) is statistical, and based on the interactions between light in form of a wave (i.e. a large number of photons) and the charges in the device.
Without accounting for the exact interaction between a single photon and an optical device in its entirety, any statement regarding how an optical device may affect the behavior of a single photon is meaningless.
This realization negates all conclusions from all experiments (thought or actual) based on a “single photon – optical device” interaction (which are many).
1. Rafael Chaves, Gabriela Barreto Lemos, and Jacques Pienaar;  “Causal Modeling the Delayed-Choice Experiment”, Phys. Rev. Lett. 120, 190401 – Published 7 May 2018
2. J. A. Wheeler, in Mathematical Foundations of Quantum Theory, edited by R. Marlow (Academic Press, New York, 1978).
3. H. Paul, Photon antibunching, Rev. Mod. Phys. 54, 1061 (1982). 

Add-on from 12/24/2018
In “Cosmic Bell Test Using Random Measurement Settings from High-Redshift Quasars” (PHYSICAL REVIEW LETTERS 121, 080403 (2018))
The authors write: quote: “The entangled photon source … generated fiber-coupled photon pairs … in a state close to the maximally entangled Bell state. … Each photon was guided to a transmitting telescope (Tx) and distributed via free-space optical channels to the receiving stations of Alice and Bob. Each station consisted of a receiving telescope for entangled photons (Rx), a polarization analyzer (POL).”

The whole experiment and the following analysis of it is based on the assumption that the photons reaching the receiving stations are the same photons which had been initially generated.
But following the previous argument, there is non-zero – and not accounted for – probability that the originally generated photon (or photons) was (were) absorbed, hence the measured correlations between the photons registered by the receiving stations include correlations between different types of photons.
Quasar photons also have been in a contact with different materials which may have affected their properties, or absorbed and re-reemitted some of the photons.
The authors write, quote: “Within an optically linear medium, there does not exist any known physical process that can absorb and reradiate a given photon at a different wavelength along the same line of sight, without violating the local conservation of energy and momentum”
This statement demonstrates that the authors are aware of a possible absorption of some of the photons and the further replacement of those photons with new ones. They state as the fact that the new reradiated photons will the same wavelength as the absorbed photons. 
This fact is correct - ish.
This fact is correct - on average! - for a large number of photons, i.e. for an electromagnetic field traveling through a transparent medium. But I would like to see a proof of that fact/statement for a single photon colliding with a single electron in such a complex system as an atom. Plus, the authors ignore possible multi-photon events.
In the end, we need to assume that he process of absorption and reradiation may alternate the state of quantum coherence between different photons, and that option has not been considered among the ones which could, quote: “lead to corrupt choices of measurement settings within our experiment”.
However, when the goal of an experiment is to probe quantum correlations, the process which may alternate those correlations is the most important to be considered as a reason to corrupt an experiment.
In the end, the described experiment does not allow to established if the result describes solely the properties of entangled photons, or it describes the properties of a large system which was including entangled photons but also was affecting those photons in a non-accounted way.
The two specific examples reported in this piece demonstrate a very common situation when authors try to analyze the behavior of a microscopic system ignoring possible effects of the interaction between the system and the macroscopic measuring device (as the whole) beyond the effects the authors are looking for (beyond the possible states of the detectors). It is also a common case when authors apply properties of the interaction between a medium and a macroscopic number of microscopic particles to the interaction between a microscopic particle and a particle of the medium without having proved the possibility of this transition.
That proof should be based on the analysis of the evolution of a state-vector (wave-function) of a single photon (or two photons, to study the entanglement); the evolution is governed by a Hamiltonian; everything which may affect the photon (or photons) before it reaches a detector (before being measured, before wave-function gets "collapsed") must be a part of the
Hamiltonian; otherwise the theory does not describe the actual phenomenon.

Note: this post represents a formalization of one of the ideas discussed in my previous publications on the foundations of quantum mechanics, such as:
The Uncertainty Principle: a contemporary formulation.

Appendix I
 Your_manuscript LZK1101 Voroshilov
Re: LZK1101
    Comment on ``Causal modeling the delayed-choice experiment''
    by Valentin Voroshilov

Dear Dr. Voroshilov,
Your manuscript has been considered. We regret to inform you that we have concluded that it is not suitable for publication in any APS journal.

Yours sincerely,
Robert Garisto
Physical Review Letters

Celebrating 125 Years of the Physical Review   #PhysRev125

The rejection did not come as a surprise at all, I expected it.
But it demonstrates how APS operates.
This was not my first review, for example, check this link (at the end of the piece).
I also have been reviewing publications on physics education.
For example:

Decision on an article you reviewed: EJP-103392
Re: "Using Algebraic Reasoning to Model Gravitational Fields and Forces" by …

Thank you for your comments on this Paper being considered by European Journal of Physics. We wanted to let you know that we have now made a decision on this article based on all of the feedback received. On this occasion our decision is: Reject

If you would like to see the referee reports for this article, they are now available by viewing the decision letter for this article in your referee centre at .

We are very grateful for your assessment of this paper and we look forward to working with you again in the future.

Yours sincerely

On behalf of the IOP peer-review team:
Jessica Thorn - Editor
Dr Stephanie White – Associate Editor
Lucy Joy – Editorial Assistant

and Iain Trotter – Associate Publisher

IOP Publishing
Temple Circus, Temple Way, Bristol
Here are some examples of my reviewing practice (our of 13, so far):
As one can see, there is a difference between how APS reviewers operate, and how I operate as a reviewer.
When an author makes a claim, a reviewer has only six options to choose from.
1. The claim is wrong.
2. The claim is correct and significant.
3. The claim is correct and significant, but it has been already previously made, hence, not original.
4. The claim is correct but insignificant.
5. The claim is not clear, but may be correct and significant.
6. The claim is not clear, but even if will be correct, it will not be significant.
In any case, a reviewer can address the claim.
If that is not a case, it simply means a reviewer does not assess the claim, the reviewer assesses an author, and finds the author insignificant (does not deserve the reviewer’s time).
It is not a surprise to me that some reviewers may act in such a manner; they are people after all. The fact that they do science does not automatically mean that they also conduct a scientific behavior.
If someone can skillfully manipulate by a sophisticated machine which makes complicated parts for a space shuttle, would we call that one "an engineer"? Doubtful. The one does not design the parts, doe not have a big picture of how different parts should work together. the one is a technician. There are also many "scientific technicians". Someone who can skillfully apply a sophisticate algorithm to generate some new data. But the algorithm was developed by someone else. And the data mined in the process do not relieve anything truly unexpected. Such a person, though, can be a very good manager, skillful organizer, and make decisions about scientific importance based on how close the ideas are to his own.
This fact has already been described in literature, for example, in books like:
but especially, in 

Appendix II

I know why it is on hold. In this tiny paper, with no single equation, even no single number (can you imagine - no math!), I go right to the essence of a physical phenomenon (and as a very successful physics teacher, and more, I claim that that is the essence of physics). My claim affects numerous publications which use the evolution of a single photon (just Google "a single photon experiment") as the engine for arriving at final conclusions. The authors of those paper will have to find a fix (do math). 
That fix may be trivial. 
Or may not exist.
What I am curious about is who keeps it on hold?
New technologies allow reaching out to a wide audience bypassing established root. For example, in three says after the publication, this piece has reached 61 people.  
To this day (12/21/2018), my three blogs reached more than fifty thousand people (combined). I wonder, how many people have read the works of my reviewer?
 Appendix III
Yesterday (well, technically, already today), while I was falling asleep, it came to me!
Take a "classical" electron diffraction experiment. 
Everyone asks a question "How does an electron "know" where to hit a screen?" But the more interesting question is, "how does it "know" where NOT to hit a screen?" Restrictions on values of physical quantities is one of the most striking differences between quantum and classical mechanic. There are locations on a screen which will never be reached by an electron. But a screen is just a device which stops an electron and makes it seen where it was stopped. A screen can be moved closer or farther away (relative to a carbon crystal playing the role of a diffraction grating). That means that in the space beyond the carbon crystal there are lines, or surfaces where an electron can never be. Take a carbon crystal out, and an electron will be able to be at any location. Place a carbon crystal in, and the space changes, in the space beyond the carbon crystal there are locations where an electron can never be
A carbon crystal changes the space.
I imagine that changed space like a set of grooves with different deepness (in terms of epistemology, those grooves play role similar to Bohr's orbits). Those which have deeper troughs represent paths with a higher probability of an electron to travel. And the crests represent locations where an electrons cannot be (the Feynman's path for those lines/trajectories has zero amplitude). Of course, this picture implies that at any given instant an electron is located at a certain point in space, it is not smeared around all over space like a physical wave.
The motion of a particle heavier than an electron is not affected as mach as of an electron. A macroscopic particle does not "feel" any grooves at all.
By making a crystal larger and larger, by adding more and more atoms, grooves become more and more overlapping, and eventually, the space is "flattened".
But a crystal is made of atoms. The resulting change in space due to a crystal is the result of interposition (overlapping, interference - described by probability amplitudes (?)) of the changes in space due to an individual atom.
Atoms are made of particles.  
The resulting change in space due to an atom is the result of interposition (overlapping, interference) of the changes in space due to an individual particle.
Finally, we have reached the main point of this idea.
Every single particle changes space around it.
It is like in the Einstein's theory of general relativity.
An empty space is flat (I know, it is a space-time, and it may be disturbed by a gravitational wave, but as physics always does, we are starting from the simplest model).
If we place a heavy star in space, the space bends.
To see how it bends, we shoot light and observe its trajectory (does not have to be light, can be any object).
Now, on a microscopic level, we do the same.
An empty space is flat.
We place a particle in it, and space changes; we don't know yet - how it changes, but we know - it does. 
Each additional particle leads to an additional change.
To see that change we shoot a photon, or an electron, or another particle, which travels in a changed space.
That change may NOT be static (like bent but static space around a static star); in fact, most probably it is stochastic and leads to the existence of stable and unstable configurations (e.g. Bohr's energy levels). That change also may propagate faster than light ("spooky action over distance").
The mathematical description of this approach should lead to the Schrödinger's equation. 
Since we need to understand how a microscopic particle affects space, most probably we need to figure out how to quantize gravity.
For example, the metric tensor may represent only the average value of the space-time metric. The actual value of each component of the metric tensor stochastically fluctuates around the average one.Calculating averages or correlation factors implies using some other parameters as independent variables (at least one) - the meaning of those variables is not known (extra dimensions? spin? another actual field?). Placing a particle in an empty space changes the stochastic properties. The equations for the parameters describing stochastic properties of the space-time in the presence of particles may have stable solution for only specific values of some of the parameters (masses, charges). In a way, this approach is ideologically similar to the Einstein's (and others) approach to a united field theory, but now with an addition of a stochastic component to it. 

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