Basic Double Slit Experiment Question

[Strange]

 

I'm just saying that QED doesn't appear to work as an explanation. If someone could explain how it works for a single photon (in terms of this discussion), I would much appreciate it !

 

Feynman explains in great detail how it works. (He also says we don't know why it works, if that is what you are really asking.)

 

At some point, you run out of explanations (there is another video of Feyman explaining this with regard to "how do magnets work"). Even if/when there is another theory that explains why the QED calculations work, you will just ask, "yes, but why?" about that theory.

 

So, currently, the only answer is: we don't know. That will be the answer in future, but to a different question. That is one of the exciting things about science! Always more to learn.

 

If you are looking for some sort of certainty or truth, then perhaps you need philosophy or religion.

Edited August 7, 2014 by Strange

[swansont]

 

Yes, the QED calculations are covered in detail, and I have no problem with their accuracy and ability to agree with what is observed.

 

I'm just saying that QED doesn't appear to work as an explanation. If someone could explain how it works for a single photon (in terms of this discussion), I would much appreciate it !

 

 

If the response is going to be: it is not possible to explain - QED works as a calculation, the calculation is all that is required of Physics?

 

That is okay, but it should be clearly stated that QED is just a means to calculate, and QED is invalid as an explanation...

 

 

Why does "the photon takes all paths, and most of them interfere and result in no signal" not work as an explanation?

[Delbert]

 

Why does "the photon takes all paths, and most of them interfere and result in no signal" not work as an explanation?

The maths is somewhat above me, but I understand the other paths are significant. Whereby Feynman's diagrams provided a solution to errors in calculations when taking it as a single object moving from A to B.

[robinpike]

 

 

Why does "the photon takes all paths, and most of them interfere and result in no signal" not work as an explanation?

 

The 'many paths' explanation is plausible for the double slit experiment, since there the 'interfering paths' of the single photon progress side-by-side and so can occur and overlap at the same time.

 

However, for the partial reflection of light from a block of glass, the 'interfering path' that comes from the photon reaching the back surface of the glass and being reflected back, that path returns to the front of the glass at a different (later) time - and so the reflected path from the back of the glass cannot interfere with the reflected path from the front of the glass.

 

This means that the amount of light reflected from different thicknesses of a block of glass, for example it can vary between 0% to 16% depending on thickness of the glass, must have a different explanation to the 'many paths / interference' explanation offered by QED. (Even though, as a calculation, QED agrees with experiment.)

 

The variation in the light reflected from the block of glass experiment, suggests that there is something varying (I don't know what) with the atoms in the block of glass, and it is this that is involved in the reflection of the light, and the variation in the 'whatever' depends on the thickness of the glass.

Edited August 8, 2014 by robinpike

[Strange]

 

This means that the amount of light reflected from different thicknesses of a block of glass, for example it can vary between 0% to 16% depending on thickness of the glass, must have a different explanation to the 'many paths / interference' explanation offered by QED. (Even though, as a calculation, QED agrees with experiment.)

 

I don't see why the many paths explanation isn't equally applicable to that: you consider all the paths taken. "Proceeding side by side" is irrelevant because the outcome of the double slit experiment can be changed by things that happen after the interference pattern is formed (the delayed choice version of the experiment). So timing is irrelevant.

 

We know (from theory, from experiments like this, and entanglement and ...) that quantum effects are inherently non-local in both time and space. They are affected by things that happen elsewhere and in the past and the future.

 

That is why the QED calculations work: every path and every possible interaction has to be considered because it will have an effect on the outcome. At the simplest level things that are closer (the other side of the galss) will be more significant than, say, reflection off the surface of Pluto next Tuesday.

Edited August 8, 2014 by Strange

[robinpike]

 

I don't see why the many paths explanation isn't equally applicable to that: you consider all the paths taken. "Proceeding side by side" is irrelevant because the outcome of the double slit experiment can be changed by things that happen after the interference pattern is formed (the delayed choice version of the experiment). So timing is irrelevant.

 

We know (from theory, from experiments like this, and entanglement and ...) that quantum effects are inherently non-local in both time and space. They are affected by things that happen elsewhere and in the past and the future.

 

That is why the QED calculations work: every path and every possible interaction has to be considered because it will have an effect on the outcome. At the simplest level things that are closer (the other side of the galss) will be more significant than, say, reflection off the surface of Pluto next Tuesday.

 

I didn't know that the QED calculations included paths that exist at different moments in time?

 

So the probability of any one path is not just related to how far away the path is from the 'overall path', but also how far the path occurs in the past or the future?

 

As an explanation, QED is sounding more and more far fetched ! So now it involves time travel ?

 

I don't see why the many paths explanation isn't equally applicable to that: you consider all the paths taken. "Proceeding side by side" is irrelevant because the outcome of the double slit experiment can be changed by things that happen after the interference pattern is formed (the delayed choice version of the experiment). So timing is irrelevant.

 

We know (from theory, from experiments like this, and entanglement and ...) that quantum effects are inherently non-local in both time and space. They are affected by things that happen elsewhere and in the past and the future.

 

That is why the QED calculations work: every path and every possible interaction has to be considered because it will have an effect on the outcome. At the simplest level things that are closer (the other side of the galss) will be more significant than, say, reflection off the surface of Pluto next Tuesday.

 

The above fails...

 

When the block of glass used in the experiment is say 10 metres thick, the interference from the path that comes from the back surface of the glass, the above says that path would be negligible - as it is so far away (and so far ahead in the future !)

 

And yet, when the experiment is performed, and a millionth of an inch is shaved from the back surface of the glass, the amount of reflected light from the front surface changes.

Edited August 8, 2014 by robinpike

[Strange]

So now it involves time travel ?

 

That is as misleading as saying that entanglement involves instaneous communciation (it doesn't).

 

 

QED is sounding more and more far fetched

 

Eppur, si muove. <shrug> Nature doesn't have to appeal to your intuition. Especially when your intuition ultimately derives from the survival requirements of apes living in jungles (or whatever).

 

 

When the block of glass used in the experiment is say 10 metres thick, the interference from the path that comes from the back surface of the glass, the above says that path would be negligible - as it is so far away (and so far ahead in the future !)

 

You seem to be taking my crude appoximation of what the calculation involves a little too seriously.

[robinpike]

Strange, I appreciate your input.

 

The problem is that the idea of multiple paths being the reason for the variation in the amount of reflected light from blocks of glass of different thickness - is that it doesn't hold up to close scrutiny.

 

My points above stand as valid reasons why.

[Strange]

Multiple paths are not the reason; they are a way of describing the reason. The reason is non-locality.

 

"Multiple paths" and the calculation in QED is just a way of accounting for the nonlocality of quantum effects.

 

How else would you quantify the effect of everything in the universe, other than by summing every possible path and interaction (with the appropriate weighting).

 

It is like the way any sound can be represented by the (weighted) sum of sinewaves of different frequencies. The more frequencies you include (with ever smaller contributions) the more accurate your representaiton will be. That doesn't mean that a car engine has an infinite number of sinewave generators. Similarly, I wouldn't say the ,multiple paths are real.

 

 

My points above stand as valid reasons why.

 

As the theory works and you are therefore wrong, your points are not valid.

Edited August 8, 2014 by Strange

[robinpike]

Multiple paths are not the reason; they are a way of describing the reason. The reason is non-locality.

 

"Multiple paths" and the calculation in QED is just a way of accounting for the nonlocality of quantum effects.

 

How else would you quantify the effect of everything in the universe, other than by summing every possible path and interaction (with the appropriate weighting).

 

It is like the way any sound can be represented by the (weighted) sum of sinewaves of different frequencies. The more frequencies you include (with ever smaller contributions) the more accurate your representaiton will be. That doesn't mean that a car engine has an infinite number of sinewave generators. Similarly, I wouldn't say the ,multiple paths are real.

 

 

As the theory works and you are therefore wrong, your points are not valid.

 

No - just because the calculations work, doesn't mean that the theory is valid as an explanation.

 

For example, the movements of the planets around the sun can be calculated accurately using formulae based on the planets being black holes - such an approach works but isn't a correct explanation of reality.

 

The confusion arises when the terms 'calculation' and 'theory' are innocently treated as having the same consequence.

 

For example, the Law of Gravity (a set of equations) allows us to calculate how bodies with mass influence each other - but having those equations doesn't allow us to explain gravity, it doesn't explain the mechanism of how gravity works. It doesn't even allow us to understand what mass is.

[Delbert]

However, for the partial reflection of light from a block of glass, the 'interfering path' that comes from the photon reaching the back surface of the glass and being reflected back, that path returns to the front of the glass at a different (later) time - and so the reflected path from the back of the glass cannot interfere with the reflected path from the front of the glass.

 

Then obviously it is not reflected as we understand reflected.

 

It seems to me our minds are stuck on this business of particles trying to be waves or vice versa. It seems to me the plain fact is, from various experiments, that these things (if one can call them a thing) aren't like anything we might even possibly visualise as an object - or even a wave.

 

What's more, if they we're a 'thing' or sort of actual object, it also seems to me we'd have an even greater problem explaining them! For the simple reason whereby a thing or object, as we understand as an object, would have all sorts of other properties that objects have. It certainly wouldn't be anything like elementary - indeed, simply a small version of an everyday object.

 

For me an analogy might be the positive holes in a semiconductor. I understand they behave like a positively charged object, and thus behave and move about as a positively charged electron. But perhaps as we all know, they are nothing more than a hole in a cloud of actual electrons. Doubtless some would say the positive charge comes from the associated proton of the atomic structure, but the protons of a semiconductor don't move about. The hole behaves like an actual particle (positively charged electron). But there's nothing there! It's apparent presence is a consequence of a gap in the maelstrom of electrons moving about.

Edited August 8, 2014 by Delbert

[Strange]

 

For example, the Law of Gravity (a set of equations) allows us to calculate how bodies with mass influence each other - but having those equations doesn't allow us to explain gravity, it doesn't explain the mechanism of how gravity works. It doesn't even allow us to understand what mass is.

 

So you are looking for philosophy, not science. Try two doors down the hall on the left.

[robinpike]

 

So you are looking for philosophy, not science. Try two doors down the hall on the left.

 

Not really...

 

Those were simply examples to show that a valid calculation can fail as an explanation.

 

The QED explanation using multiple paths is shown to be false by the experiment - that is science...

 

QED states that the cause of the variance in the partial reflection of light from the front surface of the block of glass is as a result of multiple paths.

 

This hypothesis can be tested by using a very thick block of glass, as now the probability of the multiple path from the back surface of the glass becomes an insignificant contribution towards the interference.

 

But the experimental results do not bear that out - as a one centimetre block of glass behaves no differently to a 10 metre block of glass.

 

Perhaps it would help if someone could calculate the QED probability of the multiple path that is reflected from the back surface of the glass, when the block is 10 metres deep, and when the block is one centimetre deep?

 

For QED to agree with experiment, that multiple path probability has to be the same for the two different blocks of glass.

 

Thanks

[Strange]

Those were simply examples to show that a valid calculation can fail as an explanation.

 

It seems your "simple examples" fail. We have a very good explanation of how gravity works, based on the geometry of spacetime. That is the mechanism. Precisely, it is the current mechanism. It is possible that a future theory will have a different explanation (although it will, obviously, have to produce the same results).

 

 

This hypothesis can be tested by using a very thick block of glass, as now the probability of the multiple path from the back surface of the glass becomes an insignificant contribution towards the interference.

 

But the experimental results do not bear that out - as a one centimetre block of glass behaves no differently to a 10 metre block of glass.

 

Every test of QED has agreed with experiment to extremely high degrees of accuracy.

 

It sounds as if you are making up a thought experiment, then making up the results and saying this contradicts theory. That is not how science works. You need to perform the experiment and do the calculations to show they are inconsistent (they aren't).

 

 

Perhaps it would help if someone could calculate the QED probability of the multiple path that is reflected from the back surface of the glass, when the block is 10 metres deep, and when the block is one centimetre deep?

 

So you can't do the calculation but you insist it produces the wrong result.

 

All of this is explained in great detail in the Feyman QED lectures.

[JoeLight]

 

That is as misleading as saying that entanglement involves instaneous communciation (it doesn't).

 

Entanglement does theoretically involve instantaneous communication, Recently some fine scientists measured the rate of transfer between to quantum particles to be more than 10,000 times the speed of light. Its likely instantaneous however we don't have the technology to measure it any better than that because our equipment is effected by time.

 

 

 

As an explanation, QED is sounding more and more far fetched ! So now it involves time travel ?

 

Saying that QED involves time travel is a ridiculous statement. The quantum realm doesn't depend anything on time or space. Time in space seem to exist only because of the behavior of the quantum realm. Its actually starting to look very much like ever since the big bang all the energy in the universe is slowly moving toward a state of equilibrium due to the probabilistic nature of particles, which seems to be responsible for the flow of time, and the interactions of these particles seems to be responsible for the localization of particles.

 

 

 

For example, the Law of Gravity (a set of equations) allows us to calculate how bodies with mass influence each other - but having those equations doesn't allow us to explain gravity, it doesn't explain the mechanism of how gravity works. It doesn't even allow us to understand what mass is.

 

The Law of Gravity is not responsible for mass. Mass effects gravity but Mass is determined by the interaction of the bosons of particles with the Higgs Field as they try to achieve there lowest energy state. Imagine the Higgs field as an invisible net. If a particle passes though the net at the speed of light without touching it than the particle has no mass. But if the net slows the particle down than the particle now has mass. The more the Higgs field slows the particle down the more mass it has. This is a proportional effect rather than probabilistic. This explains why photons are massless because they travel at the speed of light and electrons travel at near the speed of light and so they have very little mass. Particles like Protons and Neutrons are effected by the Higgs field much more and so they travel slower and have a higher mass. The higher the mass they higher the effect of gravity. This is possibly caused by something called a graviton but your right nobody knows for sure.

 

Ultimately when I comes to what is actually happing to a particle when its not interacting is impossible to tell. You have to interact with it to even know its existence. Its like if I have a colored light in a box with a switch that turns the light off when the box is opened. If you want to know what color the light is you have to open the box to look at it. Unfortunately when you open the box the light is gone and you have no way of telling what color it was before you opened the box.

 

The Dual nature of particles acts as the switch that's blinding us from seeing what is going on when a particle isn't interacting. This dual nature also provides us with 2 different states a particle can be in. Much like the on/off switch. The light is on in the box but nobody can see it. Now if I write open me on the box and I randomly carry the box around I would be simulating the probabilistic nature of particles.

 

If carry the box out in the middle of a field its not likely anybody will open the box and the light will remain lit. But if I carry it though the local mall someone is much more likely to open it and the light will switch from on to off. That person can see that there is a light bulb and can say the light exists but is completely oblivious to what it color the light was before the box was opened.

 

QED mathematically predicts the likelihood the interaction will occur just like predicting the likelihood somebody will open my box. It cant tell us what the particles are doing when the is no interaction occurring, nor does it attempt to. Knowing what the particles do when they are not interacting seems to be impossible because our ability to observe anything is restricted to observing there interactions. If no interaction occurs then we cant see it. If nobody opens the box you don't even know the light is there. This is the problem that we have with the Quantum realm.

 

Rather than viewing quantum mechanics as having to follow the classical laws of physics (because it doesn't) try to remember quantum mechanics is governing the classical laws of physics. Its absolute simplest form of math there is. If you only have 2 particles they ignore each other or interact with each other. We as beings of interaction can only see them when they interact. Its all random chance at this level. There are so many interactions going on at the same time though that you cant see the absence of interactions unless we do an experiment like the double slit. 1 simple rule governs the universe. Chance. On/off, yes/no, is/isn't etc.

Edited August 8, 2014 by JoeLight

[Enthalpy]

Are you really sure that the Brout-Englert-Higgs boson explains the mass of all particles?

[JoeLight]

I think it makes to much sense to not continue and see how far that route gets us.

[swansont]

No - just because the calculations work, doesn't mean that the theory is valid as an explanation.

 

For example, the movements of the planets around the sun can be calculated accurately using formulae based on the planets being black holes - such an approach works but isn't a correct explanation of reality.

 

That's a non sequitur. The equations that predict the movement of planets do not depend on whether or not the objects are black holes. Mass is mass.

 

The confusion arises when the terms 'calculation' and 'theory' are innocently treated as having the same consequence.

 

For example, the Law of Gravity (a set of equations) allows us to calculate how bodies with mass influence each other - but having those equations doesn't allow us to explain gravity, it doesn't explain the mechanism of how gravity works. It doesn't even allow us to understand what mass is.

No, it doesn't. Science never promised that it would. Science s about explaining how things behave in nature, not necessarily why they behave that way.

 

 

But the experimental results do not bear that out - as a one centimetre block of glass behaves no differently to a 10 metre block of glass.

 

What's the reference to this experiment? (Journal, date, page number, etc)

 

Perhaps it would help if someone could calculate the QED probability of the multiple path that is reflected from the back surface of the glass, when the block is 10 metres deep, and when the block is one centimetre deep?

 

For QED to agree with experiment, that multiple path probability has to be the same for the two different blocks of glass.

 

I don't think QED will give you the answer you are naively expecting.

Entanglement does theoretically involve instantaneous communication, Recently some fine scientists measured the rate of transfer between to quantum particles to be more than 10,000 times the speed of light. Its likely instantaneous however we don't have the technology to measure it any better than that because our equipment is effected by time.

 

No, they concluded that "spooky action" has a lower speed bound of 10,000c, but entanglement does not behave as Einstein described, i.e. that's what Einstein called it, not what QM calls it. I think you'll find that they were concluding that QM is nonlocal, not that there is superluminal hidden variable communication.

 

From these observations we conclude that the nonlocal correlations observed here and in previous experiments[1] are indeed truly nonlocal. Indeed, to maintain an explana- tion based on spooky action at a distance one would have to assume that the spooky action propagates at speeds even greater than the bounds obtained in our experiment.

http://arxiv.org/pdf/0808.3316v1.pdf

[Enthalpy]

I feel fruitless to discuss 10m glass blocks, because I never found glass of important thickness - probably impossible to cool within a reasonable time - and glass gets quickly opaque: through 0.3 width or length you don't see anything.

[Delbert]

...and glass gets quickly opaque: through 0.3 width or length you don't see anything.

Except for fibre optic.

[robinpike]

 

What's the reference to this experiment? (Journal, date, page number, etc)

 

 

I don't think QED will give you the answer you are naively expecting.

 

 

I don't know the journal reference, but Richard Feynman knew about the experiment as he refers to its results in his book 'QED The Strange Story Of Light And Matter', on page 21 in the Introduction.

 

"As we continue to substitute still thicker layers of glass - we're up to about 5 millionths of an inch now - the amount of light reflected by the two surfaces reaches a maximum of 16%, and then goes down, through 8%, back to zero - if the layer of glass is just the right thickness, there is no reflection at all. (Do that with spots!)

 

With gradually thicker and thicker layers of glass, partial reflection again increases to 16% and returns to zero - a cycle that repeats itself again and again (see Fig. 5). Newton discovered these oscillations and did one experiment that could be correctly interpreted only if the oscillations continued for at least 34,000 cycles! Today, with lasers (which produce a very pure, monochromatic light), we can see this cycle still going strong after more than 100,000,000 repetitions - which corresponds to glass more than 50 meters thick. (We don't see this phenomenon every day because the light source is normally not monochromatic.)"

 

My issues with QED still stand when considering either experiment...

 

With the partial reflection of light from glass:

 

1) The reflection from the front surface occurs at a different time to when the 'reflected' light from the back surface returns to the front surface - and so a single photon cannot be using the QED mechanism.

 

2) QED mechanism does not explain how partial reflection can be 'turned off' or 'amplified', for example, zero partial reflection.

 

And with the two slit experiment:

 

If either of the two slits is closed, then the number of electrons / photons reaching the screen is halved. This shows that half of the electrons / photons were passing down that path. If a barrier is used that absorbs the electrons / photons if they reach any part of the barrier, then QED is inconsistent in when it treats the electron / photon as a particle, and when it treats the electron / photon as a wave.

 

1) When travelling down a slit, QED treats the electron / photon only as a particle - for if the electron / photon were a wave at the point of entering the slit, or during its passage down the slit, then what would stop the wave from touching the sides of the slit and the barrier absorbing the electron / photon?

 

2) How is it that only once the electron / photon emerges from the slit that QED then treats the electron / photon as a wave?

Edited August 13, 2014 by robinpike

[swansont]

I don't know the journal reference, but Richard Feynman knew about the experiment as he refers to its results in his book 'QED The Strange Story Of Light And Matter', on page 21 in the Introduction.

 

"As we continue to substitute still thicker layers of glass - we're up to about 5 millionths of an inch now - the amount of light reflected by the two surfaces reaches a maximum of 16%, and then goes down, through 8%, back to zero - if the layer of glass is just the right thickness, there is no reflection at all. (Do that with spots!)

 

With gradually thicker and thicker layers of glass, partial reflection again increases to 16% and returns to zero - a cycle that repeats itself again and again (see Fig. 5). Newton discovered these oscillations and did one experiment that could be correctly interpreted only if the oscillations continued for at least 34,000 cycles! Today, with lasers (which produce a very pure, monochromatic light), we can see this cycle still going strong after more than 100,000,000 repetitions - which corresponds to glass more than 50 meters thick. (We don't see this phenomenon every day because the light source is normally not monochromatic.)

 

I don't have that book in front of me, so I don't know if he referenced anything, but if you were to track it down it might contain the calculation you're looking for. I can tell you one thing — Feynman's explanation contains a vital clue: the "pureness" (i.e. the linewidth and coherence) of the light plays a crucial role, because that tells you how much phase variation you will get with distance and with angle. I have no doubt that the experiment conforms to the equations of the physics.

 

Contrast that with your claim that "the probability of the multiple path from the back surface of the glass becomes an insignificant contribution towards the interference". Why would that be? I don't see anything you've presented to support this bald assertion. As I said, I don't think that an actual investigation into the physics will agree with your naive assumption. As long as the light and the material are of sufficient quality, the interference will be the same as for thinner materials

http://en.wikipedia.org/wiki/Thin-film_interference

 

 

My issues with QED still stand when considering either experiment...

 

With the partial reflection of light from glass:

 

1) The reflection from the front surface occurs at a different time to when the 'reflected' light from the back surface returns to the front surface - and so a single photon cannot be using the QED mechanism.

 

2) QED mechanism does not explain how partial reflection can be 'turned off' or 'amplified', for example, zero partial reflection.

 

The variation, as has been mentioned several times now, is an interference effect. See the above link.

 

 

And with the two slit experiment:

 

If either of the two slits is closed, then the number of electrons / photons reaching the screen is halved. This shows that half of the electrons / photons were passing down that path. If a barrier is used that absorbs the electrons / photons if they reach any part of the barrier, then QED is inconsistent in when it treats the electron / photon as a particle, and when it treats the electron / photon as a wave.

 

1) When travelling down a slit, QED treats the electron / photon only as a particle - for if the electron / photon were a wave at the point of entering the slit, or during its passage down the slit, then what would stop the wave from touching the sides of the slit and the barrier absorbing the electron / photon?

 

2) How is it that only once the electron / photon emerges from the slit that QED then treats the electron / photon as a wave?

 

No, physics treats the electron as a wave that has certain quantized properties. If you persist in misrepresenting what the physics predicts, you will continue to find these phantom inconsistencies. Perhaps you could start viewing these inconsistencies as flaws in your understanding of the physics rather than in the physics itself.That would certainly speed things up.

[Strange]

 

With the partial reflection of light from glass:

 

1) The reflection from the front surface occurs at a different time to when the 'reflected' light from the back surface returns to the front surface - and so a single photon cannot be using the QED mechanism.

 

2) QED mechanism does not explain how partial reflection can be 'turned off' or 'amplified', for example, zero partial reflection.

 

You just quoted from a text that explains (albeit informally, by way of analogy, without mathematics) how QED accounts for these effects.

 

So how can you possibly say that QED does not work? Are you claiming that Feynman lied?

 

 

If a barrier is used that absorbs the electrons / photons if they reach any part of the barrier, then QED is inconsistent in when it treats the electron / photon as a particle, and when it treats the electron / photon as a wave.

 

It always treats it the same way. I have to second swansont's suggestion that you reconsider where the error may be.

[Delbert]

If either of the two slits is closed, then the number of electrons / photons reaching the screen is halved. This shows that half of the electrons / photons were passing down that path.

What else?

 

Perhaps if the number were the same or not in proportion the reduced slit area then that could be highlighted as bizarre.

 

In the light of the result of the two slit experiment, what would you think would be an acceptable reduction (assuming you accept it would be a reduction and not an increase)?

 

1) When travelling down a slit, QED treats the electron / photon only as a particle - for if the electron / photon were a wave at the point of entering the slit, or during its passage down the slit, then what would stop the wave from touching the sides of the slit and the barrier absorbing the electron / photon?

Your argument seems to be stuck on this business of a photon or electron being a definable object. If so, you've got to describe it as such and offer an explanation, not only of its construction (for example, a tiny billiard ball with all the properties of a billiard ball), but also how a tiny billiard ball can form a diffraction pattern.

 

I suggest you can't, for the simple reason it isn't a little billiard ball, or indeed, any object we can describe as an object.

 

It clearly isn't an object. It's probably nothing more than an event at the source followed by another event at the destination, with its apparent movement from one place to another being the transfer of energy that represents it via a maelstrom of actions and exchanges (for the want of a better explanation). I suppose one could argue as to what the maelstrom of actions and exchanges are and between. Probably something to do with momentary virtual particles, whose presence, I understand, has been indicated by experiments.

[robinpike]

The inconsistency that I am focusing on is this:

 

Using an experimental set-up of say photons and a barrier that always absorbs photons (rather than the option of reflecting them), such as a barrier coated in carbon black, these experiments can be performed.

 

1) As a test to see if the photons are ever able to pass through the central part of the barrier between the two slits, a complete barrier (without any slits) is set up to that thickness and the photons fired at the barrier to see if any photons pass through the barrier or are reflected. For arguments sake, we will take it that the results are that no photons passed through the barrier and very few photons were reflected, the vast majority being absorbed by the barrier.

 

The conclusion of this first experiment is that, whether the photons are moving as particles or as waves, they are never able to pass through a barrier of that thickness.

 

The second conclusion is that, if a photon collides with the barrier, then it is typically absorbed by the barrier, and only as an exception is it reflected.

 

2) The next experiment is set up to see how many photons are able to collide with the barrier at a very shallow angle and not be absorbed. For arguments sake, we take it that with the rough surface of the carbon black, say only 1% of the photons are reflected.

 

The conclusion of this second experiment is that, the after just a couple of multiple collisions with the barrier, all the photons will have been absorbed by the barrier.

 

3) Now we do the double slit experiment with the central barrier between the two slits is set to the thickness as used for the above, and the depth of the barrier itself being many times that thickness.

 

If the photons are passing down the slits as waves, then how do the photons make it through the slits without touching the walls of the slits and avoid being absorbed?

 

For the QED explanation of the pattern of the photons on the far detection screen, is that the photons, on exiting the slits interfere with each other's paths. This implies that the photons (whether as a wave or as multiple paths) while travelling down the slits would have encountered the walls of the slits at some point - and therefore be absorbed.

 

So the question is, if the interference is because the photons are waves, then the explanation is inconsistent with the photons being able to get through without being absorbed by the sides of the slits?

Edited August 15, 2014 by robinpike