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a reply to: Arbitrageur

The SPDC occurs at the BBO which is after the slits. To see this, look at Figure 2 as well as this relevant quote from the published paper:

From reference arxiv.org:
Instead of atomic cascade decay, spontaneous parametric down conversion (SPDC) is used to prepare the entangled two-photon state. SPDC is a spontaneous nonlinear optical process from which a pair of signal-idler photons is generated when a pump laser beam is incident onto a nonlinear optical crystal[6]. In this experiment, the 351.1 nm Argon ion pump laser beam is divided by a double-slit and incident onto a type-II phase matching [7] nonlinear optical crystal BBO at two regions A and B.

If we only get emanation from A or B, that emanation will have only come from light that passed through one slit. There are no slits downstream from A or B, there are only slits upstream. And Figure 2 is pretty clear that each region is illuminated by the single slit preceding it. (Indeed, that geometry is what allows "which path" information.) I don't see how any interference can result in a case where emanation is from only A or B, since there is no two slit apparatus downstream for such light to pass through. I believe we need both A and B to emanate to get interference.

It's really the same physical principle in the 1982 proposal, since both the A and B atoms must participate if you are going to get interference, although in the 1982 case Figure 1 shows the atoms within the slits. But there too, there are no slits downstream from the atoms, so the only way you can get interference is if both participate in emanating the entangled wave function.

Do you still disagree? If you do disagree, can you explain how interference can be achieved? I'm not trying to be difficult, I'm simply open to another opinion. I don't see any way to explain this other than my above conclusion.

Now I will admit this is strange. What it means is that (1982) the effect of the atoms in both A and B contribute to the wave function. Or (1999) the regions A and B both contribute to the wave function. That is, the wave function of an entangled pair is produced over two spatially separated regions. In turn, this raises questions about what happens in those atoms (1982) or regions (1999), as those atoms or regions are also partially transitioned until collapse occurs. And when collapse does occur, one would think that for the 1982 case a single atom would be involved, which should itself give us "which way" information. For the 1999 process perhaps you can tell us if SPDC is something that can occur partially over the two regions. (I don't know enough about the SPDC process, but I suspect it is something that can involve two regions, since the experiment shows interference.)

originally posted by: delbertlarson
There are no slits downstream from A or B, there are only slits upstream.

Let's talk about a simpler experiment, single particle interference, where we send single photons or electrons through a double slit.

As long as we don't have "which path" information, an interference pattern forms,as if the single photons or electrons are interfering with themselves, right?

But as soon as you measure "which path" information, the interference pattern disappears and you get more particle-like behavior instead of wave-like.

Now ask yourself, does it matter if you measure the "which path" information before the slit, or after the slit? The answer which you hopefully know, is that no it doesn't matter where you measure the which path information; the interference pattern disappears when you know "which path" regardless of whether you measured it right before the slit, or right after the slit, or anywhere else between the slits and the final detector.

Now think of the delayed choice quantum eraser experiment. It also shows no interference pattern if the "which-path" information is known.

But if the SPDC occurred at either A or B, and we don't know which, then we get an interference pattern. The SPDC was not the start of that photon's overall wave function as it entered the A region, it had a wave function which had some probability of passing through both the A and B slits and entering both the A and B regions of the BBO crystal. Until the final measurements of the system are made, we don't know what state the system was in before the measurement.

For the 1999 process perhaps you can tell us if SPDC is something that can occur partially over the two regions. (I don't know enough about the SPDC process, but I suspect it is something that can involve two regions, since the experiment shows interference.)

Remember the delayed choice quantum eraser is measuring 4 different types of events passing through the equipment. If the SPDC was involving two regions A and B as you question, then why doesn't the experiment show that? It shows no visible interference pattern at all.

Even if you use the coincidence circuitry to measure the 50% of the photons that show an interference pattern and the 50% of the photons that don't show an interference pattern, why would we get 50% of the photons not showing an interference pattern, if SPDC was occurring in BOTH regions A and B as you suggest? The lack of interference pattern suggests it's not happening in both. What is different between the interference pattern measurements and the no-interference pattern measurements is whether or not we erase the "which-path" information using the "eraser".

originally posted by: delbertlarson
It's really the same physical principle in the 1982 proposal, since both the A and B atoms must participate if you are going to get interference, although in the 1982 case Figure 1 shows the atoms within the slits. But there too, there are no slits downstream from the atoms, so the only way you can get interference is if both participate in emanating the entangled wave function.

Experiments seem to show this is wrong, though now it sounds like you figured out the 1982 proposal really does involve an individual atom, but only one is needed (at a time), not "both the A and B atoms must participate" as you suggest. That statement leads me to question if you are familiar with the single particle interference experiments at all. Only one particle is needed, you don't need an A particle and a B particle. A single particle can interfere with itself; strange but true, and not very particle-like behavior.

After the 1982 proposal, the experiment linked in the PBS video performed in 1999 used the BBO crystal to perform SPDC for making trackable entangled photons, but in 2001 an alternate version of the delayed choice quantum eraser experiment was performed using a different method from either of those. That experiment was written up in both a paper, and also a simplified write-up for a wider audience, both links provided here:

arxiv.org...
www.mat.ufmg.br...

From the second link is this diagram of the 1982 proposal using atoms, where again it clearly refers to a single atom being able to create the interference pattern as long as the which-path information is not known.



Notice that your statement about this experiment: "A better description, I would submit, is that ...." doesn't sound like this experiment at all, which is why I thought and still think you had or maybe still have some kind of misunderstanding. Hopefully this diagram will illustrate some of the things wrong with your "better description" which wasn't better, and give you a better understanding of the proposed experiment.

Notice in the caption where it says "An atom" and "the atom" so it is clearly referring to a single atom which can either:
-be detected as either an A atom or a B atom, providing which path information and thus destroying any possible interference pattern, or
-the single atom can somehow pass through both slits, if no which-path information is collected, and that one atom has a probability of landing on the detector which matches an interference pattern probability, which would be demonstrated by repeating the single atom experiment repeatedly to verify the predicted probabilities.

There is absolutely no reason to infer that both A and B atoms are needed to create an interference pattern as you suggest, it only takes one particle, which may be surprising, but that's what experiments show.

This is one of the more famous experiments showing such interference with single electrons:

Single electron double slit wave experiment


So there is no A electron and B electron, just one electron at a time, and it has an interference pattern probability when it lands on the screen.

This experiment claims to use single photons to create an interference pattern, but it's a video by a science educator and likely not peer reviewed and may have some slight technical inaccuracy, but it can give you an idea.


This paper about single photon interference appears to be more technically accurate than the science educator's video, though I didn't have any luck downloading the video:
Video recording true single-photon double-slit interference

a reply to: Arbitrageur

I have watched the video's.

I think the single electron double slit video actually shows a direction pattern.

The electrons have direction. And are not being generated from the same position every time. Showing as the pattern seen.

If we go back to other experiments. It is implied that a gun shooting bullets/particles is inaccurate and the bullets fly out in different directions.

I would say that the gun is accurate. But, it is the guns position which is actually changing.

If you don't know what position your particles/waves are being generated from. It leads to confusion.

originally posted by: blackcrowe
If we go back to other experiments. It is implied that a gun shooting bullets/particles is inaccurate and the bullets fly out in different directions...

It leads to confusion.

Yes there are slight differences in directions, but there is no need for confusion about the different directions. Watch this "Original Double Slit Experiment" video which uses photons from the sun which are emitted in all directions, yet there is no confusion in the demonstration of the wave properties of light. The drawback to this experiment is that he is using the full frequency range of sunlight and the different frequencies diffract differently so the interference pattern has some rainbow-like fuzziness instead of the more clear interference pattern seen in the "Single Photon Interference" video above by Veritasium, but the reason he did this was because he was trying to re-create the original double slit experiment performed by Thomas Young in 1801.

The Original Double Slit Experiment

I would say that the gun is accurate. But, it is the guns position which is actually changing.

What makes you think that? I'm pretty sure the gun position isn't changing, but particles only come out in approximately the same direction, not exactly.

So, you can send particles such as photons out in all directions, and still see interference, so I don't see any problem with that. What the experiments are generally looking for is whether the particles demonstrate a particle-like or wave-like pattern on the detector, and those patterns are distinctly different. Whether one appears, or the other, doesn't seem to be determined by the things that you find confusing, like variation in the direction of the particles. What does seem to determine whether we see interference or not is whether we measure "which path" the particle took through the double slits. For reasons we don't fully understand, that "which-path" measurement destroys the interference in which case the pattern becomes more particle-like and not wave-like. It's ok to be confused about that, since as Feyman said, nobody deeply understands the wave-particle duality.

a reply to: Arbitrageur

I would say that the gun is accurate. But, it is the guns position which is actually changing.

What makes you think that? I'm pretty sure the gun position isn't changing, but particles only come out in approximately the same direction, not exactly.

I say that because the hits being detected. Ones showing to the left, come from a right position. Vice versa. There are lower ones and, higher ones. Leading me to believe that they are showing the direction of the particles.

a reply to: blackcrowe
You can see the experimental setup in the "Single Photon Interference" video above by youtube channel Veritasium, and there is no sign the source of the particles is moving. In fact the source is a highly collimated laser which tends to reduce variation in the direction of the photons, but it doesn't eliminate that variation completely. So those photons are arriving on different parts of the screen without moving the source.

a reply to: Arbitrageur

I am falling behind on this thread again. This response will be in reply to your first post on page 380. I will get to the second one at a later time after I read the articles and watch the videos you link to.

I am afraid that you aren't understanding what I am trying to get across. My guess is that a series of conversations would clear things up quicker, as it is hard to do this with posts. But I will keep trying. I may not be being clear enough, or, my view of quantum mechanics might just be too alien to understand easily.

Let's talk about a simpler experiment, single particle interference, where we send single photons or electrons through a double slit.

For single particle interference it is my view that when you measure the which-way, you collapse the wave function during that measurement at the point of that measurement. So yes, if you do that right before or right after one of the slits you will destroy the pattern. This is because you will collapse the wave function so that it only travels through one silt (the before case) or because you collapse to only that portion that passed through the single slit (the after case). If you measure things far enough away from the slits then you need to do the math to see if there is interference or not. (Calculate to see if a significant portion of the wave function still hits two slits for the "before" case, and calculate if there is a significant contribution from both slits in the "after" case.) I've always viewed single particle interference as evidence of a real wave function collapsing instantly due to the interactions required in obtaining the measurement, and I've thought I had an understanding of quantum mechanics through this view of things.

But if the SPDC occurred at either A or B, and we don't know which, then we get an interference pattern. The SPDC was not the start of that photon's overall wave function as it entered the A region, it had a wave function which had some probability of passing through both the A and B slits and entering both the A and B regions of the BBO crystal. Until the final measurements of the system are made, we don't know what state the system was in before the measurement.

I believe the wave function is the square root of the density of the entity. That leads to a different view, I think. The argon photon has a portion of itself go through each slit. That portion can use SPDC to produce a pair of photons at A, or B, or a pair of photons that originate at both A and B. That is what I believe is going on.

Remember the delayed choice quantum eraser is measuring 4 different types of events passing through the equipment. If the SPDC was involving two regions A and B as you question, then why doesn't the experiment show that?

I did not say SPDC always involves both A and B. My assertion all along about the delayed choice quantum eraser has been that the emanation comes from A and/or B. That is, it could come from A. It could come from B. Or it could come from A and B. If you look back, you will see that in my earlier posts. However, I see that the last paragraph of my last reply might have led you to believe I meant something other than that. On that last paragraph I was referring just to the subset of events that show interference. The events that show interference come from both A and B.

Even if you use the coincidence circuitry to measure the 50% of the photons that show an interference pattern and the 50% of the photons that don't show an interference pattern, why would we get 50% of the photons not showing an interference pattern, if SPDC was occurring in BOTH regions A and B as you suggest?

In an attempt to clarify: For the results that show interference (50% in your example) I assert the emanation comes from both A and B. For the results that show no interference I assert the emanation comes from the one region, A or B, which it is known to have come from via which-way information.

One postulate to accomplish the above is that if the photons are long enough the collapse can be initiated by all of the detectors at once.

While I believe the "long photon hypothesis" works in some cases, the more I think about it, the less I like it. I continue to think this over. I'm relatively new to this interesting question. I am making progress on another hypothesis and I'll of course share if it gets mature enough.

originally posted by: delbertlarson
That is, it could come from A. It could come from B. Or it could come from A and B. If you look back, you will see that in my earlier posts.

The incoming photons have a 351.1nm, and the "split" photons have a wavelength of 702.2nm. I can only think of two possibilities for how the 702.2nm photons could come from A and B simultaneously, and neither seems likely enough to matter, so are you thinking of a third option? Or are you thinking of one of these two improbable options?

1. If a single 351.1nm photon split such that one 702.2nm photon originated from A and one 702.2nm photon from B. The pair of 702.2nm photons have a very high positional correlation, meaning this seems improbable. From a paper on spatial quantum correlations in spontaneous parametric down-conversion: " We shall also focus our attention on the spatial correlation property of SPDC in the near field, where the signal and idler beams are found to exhibit quantum correlated photon number fluctuations when measured from detection areas that image the same portion of the beam cross-section. Twin photons are indeed generated simultaneously and they remain localized in a limited region of space as a long as they are observed close to the crystal. This ”position entanglement” of the generated photon pairs can be seen as the near field counterpart of the momentum entanglement which can be observed in the far field. "

2. If two 351.1nm photons enter the crystal such that one converts to two 702.2nm photons at region A and another converts to two 702.2nm photons at region B, both at exactly the same time or let's say within one nanosecond which they claim is the sensitivity of the detector, then the A and B option is possible, but I think still highly improbable if the conversion rate is anywhere near the one in a billion rate cited in the nature article linked on the previous page of this thread, and Kim et al have to be getting low count rates for their counting method to work, which I think you pointed out. Their interference graphs show mostly double digit coincidence rates, with just a few triple digit numbers around the peak going up to 124 or so, but these are not big numbers. We would have a better idea of the rate if they mentioned how long it took to collect their data but I don't see where they mentioned that.

Quantum mechanics does provide for some small statistical probabilities of unlikely events, so I wouldn't say it's impossible that either could happen, but I think the rates of either would be low enough to be negligible. Is there another option I haven't thought of?

a reply to: Arbitrageur

I will return to your second post on page 380 later, and respond to your most recent one here.

My thinking is different from both of the two options you mention. What you write appears to me to be thinking in terms of particle formation immediately at the BBO. Particle formation is of course a particle manifestation of quantum mechanics. What I am thinking of is a realist wave underpinning for quantum mechanics at the BBO. I believe that qm waves only undergo collapse to a small size when they undergo interactions that allow for definitive measurement. When you measure in such a way as to define the spatial region, that collapses the wave function to one of the spatial regions allowed by your measurement. (But even then, the collapse is to a small region - not a point-like particle.)

So, in the case of the 351.1 nm photon impingent upon A and B we have a real wave function that occupies both regions upon impinging. Then, when interacting with the BBO that single photon - a physically extended object - produces two photons of 702.2 nm. Each of the 702.2 nm can occupy both regions A and B, just as the generating 351.1 nm photon did prior to conversion. (It is also possible for the 702.2 nm photons to collapse to A alone, or B alone, as discussed in comments above.)

SPDC is new to me. Quickly reading this morning (making my response not fully researched, please take that into account) I see that SPDC is a crystalline process, not an atomic one. A crystalline process would be indicative of being non-atomic; i.e, the process occurs over a finite spatial extent. I believe that the finite spatial extent involves all of A and B for some of the events, leading to two 702.2 nm photons that emanate from both A and B for such events.

From your recent post:

Twin photons are indeed generated simultaneously and they remain localized in a limited region of space as a long as they are observed close to the crystal.

In the above quote, note the word "observed". That observation will collapse the wave function. If we collapse it close to A or B, we will see it at either A or B. But I believe it may have been at both A and B prior to the collapse.

My thinking on these matters is of a physical model that has finite extent. This is different from the status quo view, and deviates from relativity. Relativity is a point like theory in four space. Absolute theory allows for events that have finite spatial extent, such as events that occur over the regions A and B, and not just points within A or B.

Absolute theory allows us to understand quantum mechanics.

a reply to: Arbitrageur

This is my reply to your second post on page 380.

I watched the videos on single particle interference, and there was nothing new to me. I also read the abstract and glanced through this article that you linked to and I have no reason to doubt its veracity. 40 years ago I came to the belief that single particle interference was evidence for a real wave existing in both slits of the two slit experiments. A photon, or an atom, or (more recently) a buckyball can collapse into the region of both slits if it doesn't hit the wall containing the slits. The interference pattern is easily calculable from such an assumption. But sometimes new things come along, so I read and watched. But this time, there was nothing new.

I have now also taken time to read this article that you referred me to, as well as this simplified article that you also referred me to. I have already commented on the essence of these, as you can find here. That Wikipedia article that I originally responded to was based on these 2001 experiments that you now mention, as can easily be seen by comparing the figures. When I posted the comments the first time I don't know if you took any time to think over the substance of my comments. You responded that I had reviewed the wrong source and you brought up the issue concerning our different interpretation of a comment by Feynman. We've had some good back and forth since then. I am hoping my position is becoming clear. Perhaps you can dig into the substance of my comments this time. There are still gaps in what I wrote, specifically concerning the fringe/anti-fringe aspect of things, but by and large my comments still represent my beliefs.

I will readily admit that the Wikipedia article was quite poor in comparison to the articles you linked to. I am glad you found them and posted the links. One thing I learned was that the 1982 thought experiment was different than what I had thought was being described in the 1999 paper. The 1999 paper only had a brief description of the 1982 work, so I misinterpreted some of the 1982 details. Some of my comments about the 1982 work are still viable, while others are not. However, I'd prefer now to just focus on the actual experiments, which is better anyway.

Nothing in any of the readings and videos linked to on your second post on page 380 have altered my fundamental views. If we interpret quantum mechanics as indicative of a real underlying physical wave that collapses instantly when it encounters other entities, then we can pretty much always understand what is going on. In this sense, there are no particles, just waves that sometimes collapse and localize to small sizes due to interactions. And sometimes those waves can occupy two (or more) spatially separated slits at the same time.

If you look back at my earlier post, (here's the link again) as well as all of my posts since then, I hope you can see how my view of a real collapsing wave function makes sense to describe the 2001 experiments.

Proposing something that is simple which also violates relativity often can lead to an assumption that the proposer is a novice. But I am not a novice on basic things like single particle interference. Instead, I believe nature likely is simple at her core, and I do not think that relativity should be held onto when so many answers can be had by simply returning to absolute theory.

you guys are so confused with the slit experiments, because you still think light is something that "moves" from one place in space to another place in space in a form of an particle (photon)... it does NOT !
and you think this "photon" thing can be divided in two.. NO !

Photon is just a name, a term for the interaction.. nothing that really exist ! a mathematical invention just and only !

EM radiation propagates, there is no "thing" that moves along a path crossing any barrier going anywhere...

EM radiation is the change in the the electric and magnetic field that "reconfigure" the actual state of the EM in that particular space. EM responses to the incoming "change", the slope in E and B changes but nothing actually MOVES through space... just the "information" is exchanged.

Doing this, this "slope" of the electric field and the magnetic direction is interacting with all other charged particle's electric and magnetic fields, shaping and changing itself and those of the fields it is interacting with..

now, the slit or slits or the detectors is not nothing, they are made out of charged particles ( protons, electrons ) and they also interacting with each other and the incoming change in EM ( better said E and B )

...QM states, the outcome is defined by the "observer",
I say it is true per se, but not how QM is handling it.

listen...
simple said, electron position is displaced in space -> change in the slope in E and than induced B direction -> propagation trough space ( EM field ) -> interaction with other charged particles -> detection (movement ) of the charged particle ( receiver ) -> but also very important change in the emitter E field itself ( E coupling )

yes, I say it again, E is some factor 30-200 faster than B ( has not been measured yet to my knowledge )

now... the delayed quantum eraser thing...
electron moves, EM is changing, it interacts with whatever on its way and than with a crystal that splits it in two, both "information" propagate, one detector reads, another do or do not, THIS is the moment where the E coupling is doing it's thing... the "information" is not lost in E by the first detector reaction, it is just not going to be detect by the second one...

you can't make an E field disappear into nothing !!
you can such things by "particle thinking" ( the photon didn't arrived at the position ) ( ha ha ha )
go away from that thinking !

now...
if the second detector "is reading", the first is "on the same potential" in E so it does change its interaction outcome, it has to.
if the second detector is not reading, the EM wave has a "different form" as if the detector is reading...

and about the time... there is no time measurement by the machine, just the length of the path of the so called "photon particle" and the speed of light indicates the one should be detected faster than the other !
but now... the detection is a muster build over a long time of period, the ""photons" are send one by one... think about this !

dono.. can't make it more easily

but sure, if you think of point like things that travel though space, you will never comprehend this...



have a nice Christmas !

a reply to: KrzYma

a reply to: KrzYma

never worked with any photodetectors or single photon counters ever in your life... or been anywhere near a science lab after school right...

a reply to: dragonridr



the light is made out of photons and they collide with electrons...



NO DUDE !!!
NO !


again.... NO!!!

electrons are charged particles and they of course adjust they position in the E field according to the slope in the electric potential...

there is no collision between any fictional "particle" of light, light is not a particle !!!


BTW ! getting Nobel Prize means absolutely NOTHING !
Obama has the Nobel prize for PEACE !!!

edition.cnn.com...

originally posted by: ErosA433
a reply to: KrzYma

never worked with any photodetectors or single photon counters ever in life... or been anywhere near a science lab after school right...

I'm sorry for you, I really am... you should try it some day.. you don't need a "lab" for this, you can do it in your kitchen, the kitchen will become "the lab" for experimets

listen..
I have described the photoelectric effect few hundred pages back on this thread, but I will do it again..

first.. there is no quantization in the electric field, it's an accumulating field.
means... if you add something to it, it gets stronger or weaker, depending on the "direction" of its "adding fields"

to explain..
one charged particle like an electron for example is the source for the electric field.
this electric field is stronger next to the electron than it is further away...

if you put another electron into the field, they both repeal each other. ( will tell you why in a moment... )
if you put a proton, that is charged "reversed direction" next to it, they will attract.

this alone has nothing to do with light... to have a radiation (light), the charged particle have to move.
a movement of an charged particle induces magnetic field, a field that reconfigure the E field correspondent to the change in E.
this change in charge's position in space, called radiation, propagates in the field, in all directions..
due to the vector of its displacement, it is not homogeneous, so you have geometrically speaking two waves ( the slope in E intensity )
A transverse wave is a moving wave that consists of oscillations occurring perpendicular (right angled) to the direction of the charged particle movement, and a longitudinal wave in which the displacement of the charged particle is in the same direction as, or the opposite direction to, the direction of propagation of the wave.

most radiation emitters are not just single electric charges, they're surrounded by other charged particles and because as I said, E field is an accumulating field, the surrounding atoms can add or cancel the E slope.. ( this is how lasers get they power from, from accumulation of the E field, this is how you make light shining in a certain direction, by blocking all other directions the wave propagates )

now, the photoelectric effect...
what happens when a light wave hits the metal ?? ( yes, photoelectric effect just with metals due to the "free electrons" but not with dialectics so easy... )
the "free moving" electrons change the direction in movement, because they have to respond to the E field.
if the E field is strong enough to move the electron in the direction away from the proton it is attracted to, it "flay off"...
now... if you already build an electric field that has a direction supporting it, it happens even more easily... ( detector machines )

why the measured energy needed for this "photoelectric effect" is "quantized" is not the true nature of light but this of the material the electrons have been "kicked of"... QM ? !? BS !!!
the stopping voltage varies linearly with frequency of light, but depends on the type of material only !!


enough for today...

here the actual stand of main stream physics explained by a comedian...


one thing to mention...
when he hays "we know" he means "we thing it is so"
when he says "it's a law" he means "the theory says so..."
when he says "this is the fact", he says "believe what we tell you"

some what he says is true.. all is a field


the most funny part is the equation "the theory of everything (so far)"

Gravity -> no explanation of that, just math to description what it is doing, not why!
Strong Force -> do not exist, is just made off to explain why like charge particles do not repeal at small distance
Weak Force -> do not exist, just made off to explain radioactive decay... is triggered by outside!
Matter -> no explanation of that, just math to describe what is going on, not why!
Higgs Boson -> fairy tall story !

more important, Electromagnetism...
why is is treated as one?

Electric field and magnetic field are two things not one !!

...but we all now, repeat something, doesn't matter what fairy story you tell, repeat it often enough, and people will believe this..


best on the end, when he repeats all that BS you should believe to...

ok, one from EU, ( no, I'm not EU proponent, they just fit my observations more than Quantum Particle Zoo )

background radiation...
one on that by Dr. Pierre-Marie Robitaille who made MRI what it is today



...I will not comment the dark matte and dark energy humbug

a reply to: Arbitrageur

Happy New Year. Have a great 2019.

Thanks for your replies and video's. Trying to help me understand.

But. I obviously don't, and still have questions on D/S experiments.

Can a wave be represented by/as a curve?

How many points are the least needed to plot a curve. Is it 3?

If the points are particles. Then 3 particles could act as a wave?

The least amount of particles to make a real 3d wave would be 18 particles in 6 groups of 3?

So. If 3 particles travel towards the wall with the 2 slits in it (in waveform). The centre/lead particle will be stopped by the wall. The 2 end particles would be able to travel through the slits. Onward to the detector screen?

If a detector is placed near to a slit (observation). Then 1 of the 2 remaining particles will be stopped by the observation detector, leaving the remaining particle to pass through a slit and on to the detector screen?

I realise this is probably stretching it a bit.

Sorry to keep making you bang you head against a wall.

I'm fascinated by it.

In an update to my above post.

The 18 particles i mentioned are maybe 6 groups of 3 charged particles -1, 0, +1.

They represent a photon/waveform.

Below. Is a diagram which i hope someone will understand.

It shows the interference pattern created as 2 particles (-1 and +1) emerge through the 2 slits (which i have marked with a green circle at the top and bottom of pic to show their positions). The 3rd particle (0), was lost to the wall.

I have drawn straight lines (chevrons/triangles) to represent the waveform/curve in red. Which peak at a the detector screen.

I have done the same with both slits, but in green.

Along the left hand side is my attempt to figure out how many photons are hitting the detector screen. It might be crude. But it gives me numbers i can work with and hopefully represent the real thing.

The photon hits are displayed as red dots above the detector screen.

At every peak. I have marked a zero in pen. If you follow the lines back to the wall. You find a -1 and +1. Making up the 3 particles responsible for the waveform.

The photon counts are such, because. The central total of 21 is the shortest distance travelled by photons.

The 15 counts represent a less magnitude waveform. Because they're on a curve. They have slightly further to travel, and the mag drops off by 2 in my example.

Another drop of 2 represents the 9 count.

And, another drop of 2 gives a 3 count.

a reply to: blackcrowe

first of all... there are just to ( 2 ) things we can do to describe something.

we can count... 1... 2... 3... 4... and so on
and we can measure... means, compare one thing "size" to another thing "size"

counting, if done right, is always correct
measurement, is always an approximation by a given resolution of the samples

any measurement is dependent of the one thing comparison to another.
with smaller things you compare to, the RESOLUTION gets better and better...

this is a problem for mathematics...
you just can't make things "infinitely" small and measure with those..

there is a BIG difference to " infinite " and "countless"
the mathematical infinity is a number that has no END.. is countless
so the number becomes endless big and uncountable..

"Planck length" is something the Planck invented to deal with this "infinity"
you can look up all about Planck length, Planck time and Planck constant on the internet.

this invention does not mean electric and magnetic field is made of chunks, forget it!
all those invented sizes mean, that there is not mathematical benefit to handle with sizes smaller than this.

but still, all fields are continuous, but any try to describe them "continuously" would end up in never ending numbers.
so, mathematically speaking Planks's numbers are those things we can deal with, because more is not needed.


now to your drawing...
again, light is not a particle, you can not count it, all you can count is something those waves are doing to an electron for example, you can count the electrons kicked off if light is shining on a metal plate, but this is going now from something you should measure ( compare wave length and intensity ) to something else... you can only count the electrons that interacted with the wave and have been kicked out of the metal... you can not measure the wave, there is jut not any possible thing you can build to make such an measurement.. point!

the next thing, stop thinking about the slit berries as something solid, it is solid on the paper in your drawing.
in reality the slit is made of billions of protons and electrons all having a certain "strength" in the electric field and all "reacting" to the magnetic field and adapting they position to the E field.

if an metal atom is not loosing it's electron and you don't detect it, it does not mean that there was no respond to the incoming slope in the electric field, there was, but the slope was just not enough to kick electrons out of the atom.

heating with microwaves is that thing, the waves do nothing more but change the "internal" movement of the atoms, they respond to the E slope, change the movement, get more chaotic, bounce more from each other, the matter has higher temperature..
temperature is a measurement, you measure it by comparison the volume expansion of an material that is not "hot" to that when it is "hot".. and all materials respond differently to this, so some get faster some slower "heated", its not the property of the EM wave but this of the material.

just forget quantum bull# !