Talk:Double-slit experiment

Disagreement over lead sentence

There has been a recent disagreement over the lead sentence. I wanted to get in on the discussion so I thought I'd bring it here to the talk page, if that's okay.
Zanahary prefers:

In modern physics, the double-slit experiment demonstrates that light and matter can satisfy the seemingly incongruous classical definitions for both waves and particles.

Johnjbarton prefers:

In modern physics, the double-slit experiment demonstrates that light and matter can exhibit behavior of either classical particles or classical waves.

In the top version I think the phrase "...light and matter can satisfy the seemingly incongruous definitions of..." is needlessly convoluted. I'm not sure particles and waves actually have "definitions".

In the bottom version, I understand the reason for using "or" rather than "and" - matter and light don't exhibit these properties at the same time or the same part of the experiment. But I think "or" will be confusing for nontechnical readers, they will think: "Okay, this means some matter and light exhibits particle properties and others exhibit wave properties."

I'd suggest In modern physics, the double-slit experiment demonstrates that light and matter can exhibit behavior of both classical particles and classical waves. and clarify the circumstances later, or add the phrase but not at the same time.

--Chetvorno^TALK 03:42, 15 October 2024 (UTC)

Particles and waves do have classical definitions, and “classical particles/waves” doesn’t follow any verbiage I’m familiar with. ꧁Zanahary꧂ 03:46, 15 October 2024 (UTC)

I didn't quite understand. You are objecting to the terms "classical particles" and "classical waves" in John's wording? --Chetvorno^TALK 04:50, 15 October 2024 (UTC)

Yes. ꧁Zanahary꧂ 05:51, 15 October 2024 (UTC)

Maybe instead of trying to go straight to interpretation we should start with the facts. Maybe something along this line:

• In physics, the iconic double-slit experiment, with either light or matter, displays an interference pattern built up one event at a time. The individual event are consistent with quanta or 'particles'; the pattern is characteristic of waves. Quantum mechanics predicts these results while classical theories of particles or of waves do not.

Johnjbarton (talk) 15:34, 15 October 2024 (UTC)

Certainly not. That opening sentence could hardly be more opaque. -Jordgette [talk] 15:40, 15 October 2024 (UTC)

Perhaps you would care to propose a clearer alternative? Johnjbarton (talk) 15:56, 15 October 2024 (UTC)

@Johnjbarton: Agree with Jordgette. The introduction should be understandable by general readers. I mostly like your original lead, I can live with it. But what is your objection to:...can exhibit behavior of both particles and waves? I believe a lot of sources use this wording. The same photon that is absorbed at the screen as a particle becomes part of the collective interference pattern.--Chetvorno^TALK 17:33, 15 October 2024 (UTC)

The problem with the "exhibit behavior of both particles and waves" is that the word "particle" has two meanings, a BB-like object or a quanta. Readers assume BBs but most physics articles assume quanta. That is why I want to use "classical particle".

The "exhibit behavior" is the important bit for me, not 'or' vs 'and'. We just need to avoid making claims about what light and matter "are" vs our observations. I'm ok with your full original proposed version. Johnjbarton (talk) 17:49, 15 October 2024 (UTC)

I agree with all that, and using "classical particles" and "classical waves". Just so I understand, what is your preferred wording? --Chetvorno^TALK 01:04, 16 October 2024 (UTC)

My preferred version is the one in place. But your

• In modern physics, the double-slit experiment demonstrates that light and matter can exhibit behavior of both classical particles and classical waves.

is also fine. Johnjbarton (talk) 02:40, 16 October 2024 (UTC)

I agree with the above version. --Chetvorno^TALK 03:27, 16 October 2024 (UTC)

I still don't like "classical particles" etc. Can we do In modern physics, the double-slit experiment demonstrates that light and matter can exhibit behavior of both particles and waves, classically defined.? ꧁Zanahary꧂ 18:55, 16 October 2024 (UTC)

There is a little ambiguity in whether "classically defined" refers to the particles and waves, or "behavior". But I can live with it. --Chetvorno^TALK 19:31, 16 October 2024 (UTC)

You said above that "particles and waves do have classical definitions..." so what's wrong with "classical particles" and "classical waves"? We can link the adjectives to Classical physics to give readers more info. --Chetvorno^TALK 19:45, 16 October 2024 (UTC)

I want to raise for discussion a slightly related issue. The article starts with "...experiment demonstrates that light and matter can exhibit behavior of both classical particles and classical waves. This ambiguity is considered evidence for the fundamentally probabilistic nature of quantum mechanics.", which to me reads like "the uncertainty of whether it is a wave of a particle is the uncertainty that is handled by probabilities". I guess in some quantum eraser setup that may be a valid way to describe things, but, afaik, in the classical double slit experiments the "ambiguity between wavelike and particle-like behavior" and "the probabilistic nature of quantum mechanics" refer to two completely separate uncertainties and should not be conflated like that. Maybe something like "Versions of the experiment contribute to the evidence for the fundamentally probabilistic nature of quantum mechanics." would be more accurate? ("versions", because the original Young setup is just classical wave optics, no quantum probabilities) L3erdnik (talk) 17:43, 1 November 2024 (UTC)

Hm, I don’t understand your reading. I understand it as "the uncertainty of whether it is a wave of a particle is evidence that quantum mechanics is probabilistic". Is that different from yours? Is yours an implicit derivation from this reading? ꧁Zanahary꧂ 17:50, 1 November 2024 (UTC)

Yes, that is how I think the sentence reads, which is problematic since the probabilities in quantum mechanics are related to the observables (like "4% particle is in this spot, 5% it's in that spot, etc.") rather than which properties are more pronounced (as in "40% it's a wave, 60% it's a particle"). Not withstanding specific setups tailored to tie the latter to the former. L3erdnik (talk) 18:25, 1 November 2024 (UTC)

I deleted the sentence:

• This ambiguity is considered evidence for the fundamentally probabilistic nature of quantum mechanics.

This topic is not covered in the article. Johnjbarton (talk) 18:02, 1 November 2024 (UTC)

Photon animation is not correct.

The animation in the section "Mach–Zehnder interferometer" shows particles in contradiction to science. The caption is also illogical since it claims the experiment exhibits wave-like interference but the animation persists in showing particles. Ironically the article topic is one of the key bits of experimental evidence that such a diagram is incorrect.

Photons in a Mach–Zehnder interferometer exhibit wave-like interference and particle-like detection at single-photon detectors.

An acceptable diagram would show optical paths and pulses that change when the detector is inserted in the path. Johnjbarton (talk) 17:50, 30 October 2024 (UTC)

I replaced the image with a different one from the main article. A changed the text to match. Johnjbarton (talk) 18:11, 30 October 2024 (UTC)

You put a completely classical and uninteresting picture instead of this great animation. You are really overreacting to someone drawing photons as dots. The caption is perfectly correct, the experiment does exhibit wave-like interference. Tercer (talk) 18:18, 30 October 2024 (UTC)

Both images are of course completely classical as they must be. The old caption contradicts the old image: no wave-like interference is shown in animation the two-path condition. I think the candle interference is much more interesting and it avoids showing little imaginary dots in flight. I agree that the animation is visually compelling and fun to watch, but it acts to reinforce an incorrect view of this article's topic. Johnjbarton (talk) 18:27, 30 October 2024 (UTC)

Of course wave-like interference is shown. We see it clearly as only one detector clicks after the photon paths converge at the second beam-splitter. The illustration is not showing "little imaginary dots in flight", but the region where $|\psi (x)|^{2}$ is larger than some threshold. The dots are solid red when the integral over this region is close to 1, and semi-transparent when it's close to 1/2. Tercer (talk) 18:32, 30 October 2024 (UTC)

I'm wondering whether we should have a section on the Mach–Zehnder interferometer at all, since there is a separate article on it. I doubt the brief explanation is going to be comprehensible to nontechnical readers. Maybe we could just have a sentence with a link saying that Mach–Zehnder is another split beam experiment demonstrating particle-wave duality. --Chetvorno^TALK 19:51, 30 October 2024 (UTC)

It's two paragraphs in the section "Variations of the experiment". I think it fits very well there. Tercer (talk) 22:47, 30 October 2024 (UTC)

I agree that this topic is a big step up for most readers, though most modern experiments are done this way. Since I believe the current content is unverifiable I support this solution even if it alters the structure of the article. Johnjbarton (talk) 23:44, 30 October 2024 (UTC)

I implemented this suggestion. If source for the model in the image is found we can revisit having a section. Johnjbarton (talk) 17:49, 31 October 2024 (UTC)

We need a source for this new interpretation of the double slit experiment. Then the figure caption would be incorrect as of course the dots can't be photons if they are sometimes 1/2 and sometimes not. Johnjbarton (talk) 23:40, 30 October 2024 (UTC)

The meaning of the dots and their shading is not at all clear from the caption or the adjacent article text. I would have guessed at first that the changes from solid to semitransparent were an animation bug. XOR'easter (talk) 22:27, 31 October 2024 (UTC)

Tercer had to give a whole explanation in terms of concepts that are familiar to a physicist, but not the general reader, and with a bit of thinking and figuring out (and foreknowledge of how the Mach–Zehnder interferometer works) I can parse the intent of the diagram. But it is as clear as mud without prior insight or the willingness to just treat it as magic, and even with Tercer's description the critical role of relative phase in the constructive/destructive interference is just missing from the diagram and explanation, for which illustrated waves are better. I don't think that the diagram works well here. It also ignores the quantum eraser possibilities (the detectors end up in a superposition of 'detected' and 'not detected'). Without a clearer simple presentation, I concur with Chetvorno's observation. —Quondum 21:19, 1 November 2024 (UTC)

I find your position incomprehensible. Whether you like the animation or not is independent of whether this article should cover the Mach-Zehnder interferometer. I think it clearly should; it is the most prominent variant of the double-slit experiment, and the one is often taught in its stead, for pedagogical reasons: to understand the double-slit experiment you need differential equations, whereas for the Mach-Zehnder interferometer linear algebra suffices. It would be bizarre (if not even WP:UNDUE) to ignore it while covering other more obscure variants. Tercer (talk) 21:58, 1 November 2024 (UTC)

Tercer, you seem to be uncharacteristically combative, and strangely unreceptive to the general sentiment against your position. Given this, I am going to step back and hope you start sounding a little more like your usual self in a while. —Quondum 23:51, 1 November 2024 (UTC)

I am asking for more opinions on Wikipedia_talk:WikiProject_Physics. My stand is:

• The image is not physically correct, it shows a model of unmeasured flying dots.
• No source supports this model of flying dots. The flying dots are not discussed in the article. They are not photons.
• An article like this should be extra careful not to perpetuate mythological models.
• The image should be removed unless a source can be provided and the caption can be corrected
• I tried two alternatives and both were reverted.

Johnjbarton (talk) 17:23, 1 November 2024 (UTC)

I have already explained you what the image represents. It is correct. Stop being disingenuous. Furthermore, images are usually unsourced. If you applied this impossible standard consistently you'd need to removed almost all of the images in this article, and probably half of Wikipedia's. Tercer (talk) 21:43, 1 November 2024 (UTC)

Your explanation conflicts with the caption and physics. The caption is clearly incorrect according to your description. If you included your description in the article it would be original research as it has no source. I'm not challenging every image in this article nor half of those in Wikipedia. I am challenging this image. Johnjbarton (talk) 01:24, 2 November 2024 (UTC)

You are simply repeating that it's incorrect without any elaboration. This is not productive. Tercer (talk) 15:42, 2 November 2024 (UTC)

I am not obligated to prove it is incorrect. I'm not asking you to prove it is correct. I am asking for a source that supports the claims in the caption and concepts visualized in the diagram. Our opinions on the concepts are not relevant.

Nevertheless here is my elaboration:

• The caption says "Photons in a Mach–Zehnder interferometer", but the dots split while photons do not. Saleh, B. E. A. & Teich, M. C. (2007). Fundamentals of Photonics. Wiley. ISBN 978-0-471-35832-9.
• Your own description ("the region where $|\psi (x)|^{2}$ is larger than some threshold.") contradicts the caption.
• The image claims "wave-like interference" but does not illustrate it.
• The standard mainstream quantum description of the Mach-Zehner interferometer does not use time-dependent theory. For example, Vedral, Vlatko, 'Quantum mechanics', Introduction to Quantum Information Science, Oxford Graduate Texts (Oxford, 2006; online edn, Oxford Academic, 1 Jan. 2010) Section 2.10 The Mach–Zehnder interferometer. OR Schneider, M. B., & LaPuma, I. A. (2002). A simple experiment for discussion of quantum interference and which-way measurement. American Journal of Physics, 70(3), 266-271.
• The red circles clearly depict particles. Asserting that they depict something else is disingenuous.
• Claiming that the circles are packets of probability imply the possibility of detection in that region of space. The possibility of detection eliminates the interference. This is a fundamental aspect of QM. (See https://www.feynmanlectures.caltech.edu/III_01.html or any one of dozens of books that discuss "which-way" experiments)
• The visualization of quantum systems has been a dream of physics for a century. (Griffiths, D. J., & Schroeter, D. F. (2018). Introduction to Quantum Mechanics (3rd ed.). Cambridge: Cambridge University Press; 1.2 The Statistical Interpretation). It would be extraordinary if Wikipedia could provide a tidy diagram that succeeds where so many others have failed.
• In my personal opinion many physicists use a model along the lines you outlined previously to make experimental designs and predictions. For the most part these models work, just like for the most part classical electromagnetism works. I think they work because they are similar to first order Feynman path treatments of these problems, not because the little dots "exist". But nothing in this paragraph matters for Wikipedia because these models are not published and do not in fact represent mainstream QM.

Now comes your part. Provide a source for your model illustrated in the diagram. Such a source would be very interesting, but I do not believe one exists because, very sadly, no such concept matches experimental all observations. Johnjbarton (talk) 18:22, 2 November 2024 (UTC)

So your objection is to the very idea that one can draw wavefunctions? You need to learn basic quantum mechanics. Drawing wavefunctions is done in pretty much every textbook. Plenty of wavefunctions are drawn at Matter wave, Wave packet, and Quantum tunnelling, for example. Including time-dependent ones. Your claim that is somehow "not mainstream" is just nonsense. And no, just because you plot $|\psi (x)|^{2}$ doesn't mean that you can make a measurement there and suppress interference. This is just gibberish. Tercer (talk) 13:19, 3 November 2024 (UTC)

Please stop asserting that I am making statements that I have not made. At no point have I said one cannot draw wavefunctions. I've drawn quite a number myself when I was working on photoelectron holography.

I have never seen a diagram like this one in a mainstream publication. If you have, just give us the source. Johnjbarton (talk) 17:06, 3 November 2024 (UTC)

In the video abstract of this paper, at around 0:45. Tercer (talk) 17:23, 3 November 2024 (UTC)

It's a ... confusing picture. Lots of moving dots, no indication within the picture of what the dot colors mean, blocks flashing sometimes but not all the time, no sense of what I ought to be paying attention to at each moment. At the very least, it's poorly captioned. XOR'easter (talk) 19:19, 2 November 2024 (UTC)

Agree with Johnjbarton, XOR'easter, Quondum. I don't think anyone who has not already been exposed to this experiment is going to understand the diagram. The representation of photons as particles is going to promote the erroneous idea that the photons split in half at the beam splitter. I think this diagram should not be used. --Chetvorno^TALK 20:05, 2 November 2024 (UTC)

I think that deleting this diagram would be throwing away the baby with the bath water - it is not perfect, but does illustrate the point quite well in my opinion. The problem is that the caption has to be brief and can't elaborate on all the details, but the second paragraph of the text itself does. Instead of removing this illustration (which, in my view, does help reader to comprehend the text) I propose to be more constructive about it, for example adjusting the caption to something like "Photons in a Mach–Zehnder interferometer exhibit interference (wave-like behavior) while being detected at single-photon detectors one by one, in discrete way (particle-like behavior). See the text for the details." L3erdnik (talk) 03:20, 4 November 2024 (UTC)

Your caption would be fine, except that it implies that the red dots are photons. They are not. That is the issue here. The dots have no physical meaning but they imply that particles are traveling along paths and splitting in half at mirrors. This kind of realistic interpretation is what many QM experiments have shown to be impossible.

Mach Zehnder interferometer alternate candle images

The diagram I tried to add, one you see in textbooks on Mach-Zehnder would match the caption you proposed.

The only meaning for the dots which I can come up with is this: the dots are just "fingers" tracing out active paths in the interferometer for different experimental setups. But then the animation is way off because the some half dots are still in the machine when only full dots should be shown and vice versa. The time scale is completely wonky. The animation would be correct if the paths simply highlighted as the detector moved. Johnjbarton (talk) 03:40, 4 November 2024 (UTC)

Isn't the half-dot the most natural way of visualizing a photon in a superposition state (which the text talks about)? Then, when it is measured in the upper path, the superposition collapses either to being detected up there or to continuing through the left path no longer in superposition, a solid dot. L3erdnik (talk) 04:14, 4 November 2024 (UTC)

A half a photon is not natural. The timing you describe is based on particles and not quantum mechanics. These kinds of pseudo-particles makes sense some of the time but fail in general. That's why these kinds of descriptions are not in QM textbooks. Johnjbarton (talk) 06:29, 4 November 2024 (UTC)

As I have already explained, the dots represent the region where the wavefunction of the photons is larger than some threshold. The wavefunction does split at the beam splitter, with half of each going each way. This is not a matter of interpretation, you just compute the wavefunction (as a function of time) and plot it. Tercer (talk) 07:44, 4 November 2024 (UTC)

I specifically said "a photon in a superposition state", not "half a photon". Are you objecting to representation of a superposition state as paler dots, or to the description "photon is in a superposition of states in the upper and the left arm" (then we should be talking about the text of the article first because it uses this phrasing)?

Or maybe to photons shown as being somewhat localized even before detection? Maybe normally it's not too accurate, but not in a way that matters in any way - one can modify the setup slightly to know exactly when new photon is emitted each time and then the photon would be localized in all directions - and how is it inaccurate then to represent that photon by a blob in which it is localized? L3erdnik (talk) 14:11, 4 November 2024 (UTC)

Sorry I should have challenged "a photon in a superposition state" which is what you said. A photon in a superposition state cannot be drawn. It can't be drawn as two less-bright photons. It can't be drawn as sometimes here, sometimes there. That is the core aspect of the debate about QM from Einstein/Bohr onward. You can't draw superposition.

You can draw the probability density of QM. That is the probability of detection in a specific experiment. If the experiment is "detect localized particle" then you can't get interference. To my way of thinking that means the animation should have no visual indications of interference when the detector is inserted. (This diagram does not have any clear indication of interference)

Photons are never localized before detection and we have no idea when they will be emitted or detected. The entire issue of "photons" is quite interesting and involve complex correlation experiments. But the real issue here is that the sourceable descriptions of the Mach-Zehnder interferometer uses quantum states not photons. Johnjbarton (talk) 17:34, 4 November 2024 (UTC)

The article

• Marshman, E., & Singh, C. (2016). Interactive tutorial to improve student understanding of single photon experiments involving a Mach–Zehnder interferometer. European Journal of Physics, 37(2), 024001.

Provides an extensive discussion of the topics discussed here. Under Student Difficulties there is a section entitled "3.2. Difficulties due to a single photon as a point particle model" that is particularly relevant. Johnjbarton (talk) 18:25, 4 November 2024 (UTC)

I have stared at the animation for a while. I believe I understand its intention. The creator put a lot of intention into detail. I think that I can see the intent. I think it is a not incorrect depiction of some interpretations of what is going on but not consistent with other interpretations. I think that it is probably an undue depiction of one interpretation. I don't want to debate that. The question is whether it belongs in this article. I don't think it does.

• It needs a lot of explanation to be understood. That sort of defeats the purpose of animation. It ought to support the text with an easily understood visual depiction. Instead, we need a lot of text to support the animation. I think it fails its purpose in that sense.
• Content in Wikipedia should be restricted to information paraphrased from reliable sources. It should be free of synthesis. It should not take a lot of own interpretation of the material in reliable sources. Where do you find an animation to paraphrase? How do you paraphrase an animation? In this case, I think that there is no animation in RS that this diagram is paraphrased from. I think it relies on a lot of OR to go from written mathematical descriptions to this animation. That does not mean that there can be no animations in WP. But it does mean that if it is opposed and there is no reliable source animation that it should be removed unless there is a strong consensus to keep it.
• It is too esoteric. The learned editors here in this discussion cannot agree on its correctness. The general reader doesn't have a chance.

Constant314 (talk) 17:07, 4 November 2024 (UTC)

Excellent perspective. I wish now I had challenged the image on grounds of confusion. Johnjbarton (talk) 17:59, 4 November 2024 (UTC)

Removed diagram per consensus of Constant314, Chetvorno, Johnjbarton, XOR'easter, Quondum --Chetvorno^TALK 18:33, 4 November 2024 (UTC)

The learned editors here all agree on its correctness. The only one challenging it is Johnjbarton, who doesn't know quantum mechanics. Tercer (talk) 20:40, 4 November 2024 (UTC)

It is not about correctness. It is about appropriateness. Constant314 (talk) 20:54, 4 November 2024 (UTC)

If an expert has to stare at the picture and then use their expertise to invent a "reading" of the picture that makes it not wrong, it's not a very good illustration. Personally, I think that the half-shaded dots feed into the lazy tropes about quantum mechanics (like "the cat is both dead and alive") that we should actively avoid perpetuating. XOR'easter (talk) 04:42, 5 November 2024 (UTC)

How else would you do an animation of the interferometer? Tercer (talk) 08:39, 5 November 2024 (UTC)

It seems that people are mostly irritated by "splitting of quanta" that can be read from the illustration. While I too don't see how else one might draw the superposition state of a single particle (John for some reason seems to be of the opinion that it is forbidden in principle), but maybe that is not necessary? Since the quantization of detections is a finer nuance, it might be better to be left for the text for elaboration, and then we could use John's picture and make the text match. What's wrong with that approach? L3erdnik (talk) 15:56, 5 November 2024 (UTC)

An animation could cycle between detector-in and detector-out as the current animation does. Each half of the cycle could start with no paths drawn, then the paths allowed by the configuration could progress from source to detectors. This much would highlight the blocking effect of the detector-in case. When the rays strike the detector the results could appear on the image, corresponding to interference or not. The results could be shown as detector screens being build up from photons arriving at the 1/2-1/2 vs 0-1 intensity rate to match the text. Johnjbarton (talk) 16:36, 5 November 2024 (UTC)

Let's start a new thread to talk about possible future animation of the Mach–Zehnder interferometer.

Would be more appropriate on Talk:Mach–Zehnder interferometer where other interested editors could participate --Chetvorno^TALK 18:16, 5 November 2024 (UTC)

Agreed. I will start a topic there. Constant314 (talk) 18:23, 5 November 2024 (UTC)

I did that, but now I think I may have jumped the gun. This page has many more watchers. Constant314 (talk) 18:35, 5 November 2024 (UTC)

Knowledge of the way and interference pattern

"Furthermore, versions of the experiment that include detectors at the slits find that each detected photon passes through one slit (as would a classical particle), and not through both slits (as would a wave)." - the references after this sentance are not for experiments. And it's controversial to real experiments which show that interference pattern still exist if observer knows the way of particle, those experiments are described it another part of the article: "An experiment performed in 1987 produced results that demonstrated that partial information could be obtained regarding which path a particle had taken without destroying the interference altogether." 37.57.176.109 (talk) 19:38, 2 November 2024 (UTC)

The experiment you mention is a statistical one - the experiment doesn't determine which slit a particular photon goes through, but is arranged so there is a greater probability that each photon goes through one slit than the other. As a result there will still be an interference pattern, but the interference pattern will be fainter. There is a mathematical equation, the Englert–Greenberger relation that expresses a tradeoff between the probability of the photon going through one slit rather than the other, and the brightness of the interference pattern.

An example of such an experiment would be if the laser emitting the photons is positioned so one slit, say the left, is illuminated with twice as much light as the other. This gives us partial "which-slit" information: twice as many photons would pass through that slit, so the probability that any photon hitting the screen passed through the left slit is 2/3. The result will be that the interference pattern on the screen will be dimmer than if the two slits are illuminated with the same brightness, so the probability of a photon passing through each slit is 1/2. The greater the percentage of light that goes through one slit, the more which-slit information we have, so the dimmer the interference pattern will be.

An experiment that determines with certainty which slit a photon goes through will produce no interference pattern at all. To determine which slit each photon goes through requires having detectors at the slits. A photon will hit the detector, changing its direction, which will destroy the interference between the slits. --Chetvorno^TALK 21:13, 2 November 2024 (UTC)

Possible Mach–Zehnder interferometer Animation

I would favor an animation that did not depict individual photons in transient.

Animation could cycle through two major states: 1. top detector in path and 2. top detector not in path.

State 1 begins with top detector in path. Dark pink ray propagates from laser to first splitter. Two medium pink rays propagate from splitter. Top ray stops at top detector. Bottom ray proceeds to bottom splitter. Two light pink rays propagate to bottom detectors. Top detector flashes one half of the time. Bottom detectors flash one fourth of the time.

State 1 begins with top detector not in path. Dark pink ray propagates from laser to first splitter. Two medium pink rays propagate from splitter. Both rays proceed to bottom splitter/combiner. Two medium pink rays propagate to bottom detectors. Top detector never flashes. Bottom detectors flash one half of the time.

Moved to Talk:Mach–Zehnder interferometer.

Constant314 (talk) 18:21, 5 November 2024 (UTC)

Richard Feynman's introduction to quantum mechanics lecture series.

Richard Feynman used some simple illustrations in his introduction to quantum mechanics lecture series. It was a series of six one hour lectures that he gave in his classes at Caltech. The lectures he gave on a visit to Auckland, New Zealand are available on YouTube. The lectures, and illustrations require only elementary arithmetic to understand. Without objection I think the article should have a brief essay on it. I can add a short addition to the article describing quantum mechanics "probability amplitudes" applied to the two slit experiment. It doesn't invoke "particle wave duality" or "wave function collapse". It's a simple, straight forward essay intellectually accessible to most people. Another set of illustrations applying to lenses would also help the article. Although the essay is brief everything in it can be cited to the introduction to Feynman's introduction to quantum mechanics lecture. 2600:8807:5400:7000:1176:3433:E91C:661F (talk) 19:26, 14 November 2024 (UTC)

First a hint: don't use the word "essay". On wikipedia an "essay" is a 'bad thing'. Second, the general concept in Wikipedia is to distill multiple sources; content explicitly relying on a single source is another 'bad thing'. Oh, and videos as references are also a 'bad thing' ;-)

If you propose to add a section on a simple QM treatment, maybe entitled 'Quantum mechanical formulation' using the Feynman lectures as the main reference, that sounds great. I suggest placing it after the Classical formulation. You might look at Wave-particle duality which uses images derived from Feynman's book.

Finally I highly recommend getting a login account. Existing editors don't generally take IPV6 users as serious since most edits from these users are vandalism. Johnjbarton (talk) 19:56, 14 November 2024 (UTC)

??? Quantum Gravity Hydrogen ???

??? Quantum Gravity Hydrogen ???

Acts like either a Hydrogen Particle or Hydrogen Puffball

All to do with -e magnet and +p magnet

Hydrogen (Magnets Matched) Acts like 1p (particle)

             NS
             SN

Hydrogen (Magnets Not matched - Matched - Magnets Not matched) Acts like 1s (orbital / Puffball)

             NN  NS  SS
             SS  SN  NN

Single / Double Slit properties???

Need someone who understands the physics better than me to comment on the above?

Thanks

David 176.25.69.174 (talk) 01:50, 2 December 2024 (UTC)

The talk page is for discussions about improving the article. Is there something that you want to change about this article? Constant314 (talk) 02:31, 2 December 2024 (UTC)