Where do all the interfered photons go?

[rchase]

I understand the basics of the double slit experiment.
I'm trying to imagine what would happen if one slit could operate at a 180 degree phase shift, or nearly that. The obvious answer is not much except between the slits, and even less if the distance between the slits is near the wave length.
My question is: Do the photons still exist despite not much happening (elecromagnetically)?
A step further: Do photons which are canceled by another slit gone, or do they contribute to the vacuum energy or something like that?
I realize this is complicated by wave-particle duality etc...

This is really important to me to understand this complicated and outside the box question.

 

[crissyb1988]

that question has occurred to me aswell. sorry i can't help answer it tho..

 

[netheril96]

I hardly grasp your question. What does that 180° phase shift mean? And what is this entire sentence The obvious answer is not much except between the slits, and even less if the distance between the slits is near the wave length.?

 

[StevieTNZ]

Ignore the B redness in this image:
http://upload.wikimedia.org/wikipedia/en/thumb/7/7a/E-V_bomb-testing.PNG/350px-E-V_bomb-testing.PNG
I've always been under the impression the wave accociated with the photon travels both paths, but the photon does not get destroyed because the wave both constructively and destructively interferes, so the photon is detected at one detector, not both. Hence it hasn't been destroyed.

 

[rchase]

I doubt if anyone can answer this question, I don't think our math accounts for this null energy which is all around us. Although I do not believe the photons are destroyed. The next question which occurs is to ask if everything is emitting this, and how much.
I did some homework, and it appears that these type of interactions might becalled virtual particles. It seems virtual particles violate the uncertian laws of electromagnetic and quantum physics. (I don't hope to change my topic with this commentary.)

 

[DaveC426913]

I understand the basics of the double slit experiment.
I'm trying to imagine what would happen if one slit could operate at a 180 degree phase shift, or nearly that.

You're misunderstanding.

No need to change the slits to get a 180 degree phase shift. Just look a fraction of a degree to the left of straight. There, the two waves are 180 degrees out of phase.

Try your thought experiment using water waves first, See if you can get the effect you're imagining. I suspect you won't be able to.

 

[rchase]

Exactly there are some interfered photons. My question is about the things we can't see, are there more missing photons all around us which can't be recovered? Can we setup an emitter which emits an entirely canceled wave. If so, is there a sea of photons which are essentially summing to zero. And if so, how does this affect vacuum energies and virtual interactions, or gravity for that matter...

 

[DaveC426913]

Exactly there are some interfered photons. My question is about the things we can't see, are there more missing photons all around us which can't be recovered? Can we setup an emitter which emits an entirely canceled wave. If so, is there a sea of photons which are essentially summing to zero. And if so, how does this affect vacuum energies and virtual interactions, or gravity for that matter...

How would you get two photons, emitted from two sources separated by a distance, to travel parallel, such that they stay interfered?

 

[rchase]

Glad to see you're interested, I have some bugs to work out. I would use more than two sources and many more than two photons. If I told you woudn't that spoil the invention? Do you have connections with a security clearance :)? I'm not exactly going around telling everyone how it works before I get the details worked out. I'm a physics fan obviously with some specialized interests, but by no means a PhD. Anybody could figure this out if they tried to think outside the box.
So which is it? Gravity, vacuum energy or virtual particles? I'm not getting feedback at this point; is that because I'm holding back or because nobody ever thought of it?
I can't tell you, I'm not sure what the laws are regarding inventions and security. Time to go look that up... Looks like I need to be secretive.

 

[DaveC426913]

I would use more than two sources and many more than two photons.

If you can't get it to work for two photons, it doesn't matter how many more you add into the mix.

Before you go off on an invention adventure, you should read up on the physics involved. You will quickly realize where your conceptions are leading you astray.

 

[eaglelake]

I understand the basics of the double slit experiment.
I'm trying to imagine what would happen if one slit could operate at a 180 degree phase shift, or nearly that. The obvious answer is not much except between the slits, and even less if the distance between the slits is near the wave length.
My question is: Do the photons still exist despite not much happening (elecromagnetically)?
A step further: Do photons which are canceled by another slit gone, or do they contribute to the vacuum energy or something like that?
I realize this is complicated by wave-particle duality etc...

This is really important to me to understand this complicated and outside the box question.

You are confused about the double slit experiment and about wave-particle duality, in particular. The photons are not “canceled”. They hit the detection screen one at a time and the interference pattern is built up over time by many different photons hitting the screen at different locations at different times. Where there is destructive interference in the statistical distribution, no photons ever hit that location. No photons are “canceled” there. Rather, the probability of a photon hitting that spot is zero. If you change the slit configuration, then you get a different interference pattern. There might be locations where there used to be photons, but in the new experiment there are none. Photons detected in the new experiment are not the same photons used in the original experiment. Rest assured, no photons have been “canceled”, Your question makes it sound like you believe that the photon is a particle and a wave at the same time. Not so! The photon is a particle whose statistical distribution looks like an interference pattern in the double slit experiment.

 

[jtbell]

If you change the slit configuration, then you get a different interference pattern. There might be locations where there used to be photons, but in the new experiment there are none.

And in the new experiment there are locations that receive more photons than in the original experiment. The photons simply get "redistributed." (This assumes you don't change the size of the slits, so each slit still has the same amount of light entering it.)

 

[DaveC426913]

"... I have some bugs to work out. "

Nono guys. He's got it all figured out. Just a few tweaks with a screwdriver...

 

[rchase]

I'm just saying I can create a lot of noise where the probability of sensing a photon is equally likely and homogeniously mixed so the net electromagnetic affect to the antenna is zero. So that the fluctuation in intensity of photon impacts still increases and decreases. Thank you for helping me express myself clearly. Thanks for sticking with me while I stirred the pot to get some candid response. Quantum mechanics is not a profession for me. I'm an engineer. Is a sea of photons which are equally likely similar to the vacuum energy? I think the difference would be that the photons would only impact one side of a device. (My kinks are wokring out... Thanks

 

[lugita15]

A lot of people have correctly pointed out that the double slit experiment does not destroy photons. But you should know that it is possible to create and destroy photons, so the total number of photons in the universe is not conserved. For instance, electrons can emit and absorb photons, and photons can also split up into electron-positron pairs. In fact, nature actually likes to increase the number of photons. If there are N photons somewhere, then that increases the probability that more photons will be produced there, for instance by nearby electrons.

 

[rchase]

To up the ante. Somtimes one can't be sure what the answer is until you've seen it in the lab... Consider a beam of coherent light which is recombined at half a wavelength off, I presume that can highly dim the beam.
If we put a diffraction filiter, (the equivalent of a faraday cage) in front of it, do the photons which are nearly on top of each other and are in wave opposition pass through it?

 

[rchase]

Next question #3
I presume a recombined dim beam imparts less photon momentum to a target than the two beams seperately?

 

[rchase]

So if I create a beam of light, and just interfere it destructively in a beam splitter, and the photons are not destroyed, but never appear to reach their target, because the photon pressure is zero? Were they absorbed while anti-coherent?

 

[Rap]

If you have a beam of photons and you add another beam of photons that is 180 degrees out of phase, you get no photons. Energy and momentum are conserved, so no photons are being cancelled, they are just being redirected.

Suppose you have a half silvered mirror, slanted at 45 degrees so that a beam of amplitude 1 from the bottom gets split into half to the right, half continues upward. Now direct a beam from the left. Half gets deflected up, half continues to the right. Depending on the phasing, one one or the other beam can be made to extinguish. The other beam will have amplitude 2.

 

[zonde]

My question is: Do the photons still exist despite not much happening (elecromagnetically)?
A step further: Do photons which are canceled by another slit gone, or do they contribute to the vacuum energy or something like that?

Photons still exist where there is destructive interference.
Photons undergoing destructive interference are absorbed as heat without making a "click" in detector.

Single photon interference can be nicely explained if we assume that photons are simply redistributed. However this approach will require some action at a distance when trying to explain Bell type photon experiments.

 

[Rap]

Photons still exist where there is destructive interference.
Photons undergoing destructive interference are absorbed as heat without making a "click" in detector.

[/QUOTE]

How does the absorbing medium determine whether the photon is a destructively or constructively interfered photon?

Single photon interference can be nicely explained if we assume that photons are simply redistributed. However this approach will require some action at a distance when trying to explain Bell type photon experiments.

I don't understand how. Can you explain that more fully?

 

[rchase]

I've done some 'homework'. I am advised that the wave nature only indicates a probability of where the photon will land. Also that the energy can be created and destroyed as quickly as photons interfere, but this does not mean that the photons are destroyed. A homogeneous mixture of photons in an anti-coherent combination of waves will produce a nullified interference pattern. Given we can't compute the probability of the two together, we can infer one slit from the other. The statistical probability of getting a photon from the right slit will be equal to a photon from the first slit. Therefore any particular point has an equal probability of of being reversed from the last. However, I'm still not sure if we will see them frequently at all. This type of energy is likely to generate as much heat as photons are detected, but not nearly as much as the alternative coherent wave.
If the photons together have a greater than zero probability of detection, and are directed at a single pinhole, what kind of wave emerges on the other side?
What if there are two pinholes; does it produce a cone of partially diffracted anticoherent light?

 

[ppzmis]

I understand the basics of the double slit experiment.
I'm trying to imagine what would happen if one slit could operate at a 180 degree phase shift, or nearly that. The obvious answer is not much except between the slits, and even less if the distance between the slits is near the wave length.

The phase shift at the slits is not important what matters is the phase shift between the waves passing through each slit at the point at which they are superposed. You add the electric fields of the waves at this point and square it to give you the intensity. Hence at certain points where the phase difference is zero you get constructive interference (E + E = 2E) and large intensity and at phase differences of 180deg destructive interference (E - E = 0) and no intensity. With time at a particular point the electric fields oscillate sinusoidally and hence change but the phase shift remains the same so they always cancel out. So the intensity distribution is a static pattern.

My question is: Do the photons still exist despite not much happening (elecromagnetically)? A step further: Do photons which are canceled by another slit gone, or do they contribute to the vacuum energy or something like that?
I realize this is complicated by wave-particle duality etc...

As you say this is a problem of wave-particle duality. The problem is you are trying to understand a wave problem (interference) with a particle model of photons. From a quantum mechanical point of view there is a finite probability of finding a photon at a specific point. This probability goes to zero at points where destructive interference occurs and is a maximum at points of constructive interference. This leads on to a fascinating experiment I did in my undergrad where you pass photons through the slits so slowly that only one photon travels through one slit at anyone time. What is fascinating is you still get the wave-like interference pattern, even though it seems like there should be nothing for it to interfere with! Even more fasinating is that if you actually measure which slit the photon goes through the interference pattern disappears! What this is demonstrating is the uncertainty principle. When you don't measure the photon path the uncertainty in position dx is large (something smeared out over a large spatial extent is like a wave). The uncertainty principle dxdE~hc/2pi therefore requires that the energy uncertainty is small. This has a very well defined wavelength (E = hc/lambda). But if you measure which slit the photon passes through and the wavefunction collapses and you end up with a small dx (the wave packet is well localised like a photon).

Why is this important to your question? Consider the young's slits experiment but instead of a laser use a desklamp. This will never interfere with itself because it has a small coherence length (distance over which the phase difference remains well defined). If you try and interfere two photons coming out of this lamp it will never work because photons leaving have randomly differing phases so long as the distances they have traveled differ by a tiny tiny amount. The reason a laser will interfere by contrast is it has very high coherence so the phase difference remains for much larger differences. Consequently if you have a setup where the duality means things act like waves they will interfere and the energy of the packet is spread out over a large number of wavelengths (ie it is not apropriate in QM to speak about the energy at one particular point). By contrast if you have a situation in which it is apropriate to speak about photons (energy localised) then the coherence length is tiny and hence photons through different slits will not actually interfere at all!

Cut a very long story short, what I am saying is that you can't actually have the situation you are describing, it is physically impossible, hence why we talk about wave-particle duality.

 

[rchase]

...What if there are two pinholes; does it produce a cone of partially diffracted anticoherent light? I suppose the answer would be the sum of the potential combinations.
Lastly, my question is about an antenna designed to emit a anti coherent wave.
Supposing the emitter is ramped up in a scenario similar to the photo electric effect, would photons be detected individually? (I presume so.) Then if it was ramped up, would we begin to see more and more, and then once saturated, would we begin to detect fewer and fewer photons until there appeared to be very few as they began to reduce the affect of the others? (Now reading last reply.)

 

[rchase]

I don't know that the problem of one photon is the same problem of many photons, especially in regards to anticoherent light. I suspect in cases where light is homogenously mixed, there might be the potential to encounter photons with some uncertianty. When it comes to one photon, where there is lots of room for the photon to show up else where, it can be clearly shown to be missing from another spot. Whrere there are many photons contributing to destructive interference, we'd be hard pressed to loose them all; all the time.

 

[ppzmis]

...What if there are two pinholes; does it produce a cone of partially diffracted anticoherent light? I suppose the answer would be the sum of the potential combinations.

with 2 pinholes you get an overlapping ripple pattern of two circles just like when you drop two pebbles in a lake. I don't understand what you are asking in the last half of this question

 

[ppzmis]

I don't know that the problem of one photon is the same problem of many photons, especially in regards to anticoherent light. I suspect in cases where light is homogenously mixed, there might be the potential to encounter photons with some uncertianty. When it comes to one photon, where there is lots of room for the photon to show up else where, it can be clearly shown to be missing from another spot. Whrere there are many photons contributing to destructive interference, we'd be hard pressed to loose them all; all the time.

As I tried to explain above interference is a property that is relevant to the wave properties of light. If you are visualising an experiment with particle like photons these will not interfere. This is demonstrated by the experiments I describe. If not then these are like waves and you cannot associate an energy with a particular point but with the whole wave train.

 

[rchase]

I'm receiving infractions due to speculation and personal theory. Hard get answers without speculation about misunderstanding. And hard to talk about examples of phenomena misunderstood without them being called personal theories.

 

[rchase]

ppzmis has given me something to think about. I do have some "personal misthinkings" interfering with my acceptance of theory. I'm sure this is easy to relate to.

 

[DaveC426913]

I'm receiving infractions due to speculation and personal theory. Hard get answers without speculation about misunderstanding. And hard to talk about examples of phenomena misunderstood without them being called personal theories.

Not at all! That's what the ? was invented for.

(Ask questions, rather than making statements. That's the doorway to knowledge.)

 

[rchase]

ppzmis has given me something to think about. I do have some "personal misthinkings" interfering with my complete acceptance of theory. I'm sure this is easy to relate to. Theories always seem to be incomplete, yet useful. Useful is what matters ultimately. (The point of the scientific method is to separate useful beliefs from junk.)

I am now well reminded of the fact that the electromagnetic wave can leaves the source as a wave, and interferes until a particle is detected.
Also, I am clear that once the wave is even partially affected by detection, it 'seems' to coalesce into a deterministic particle path.

I once realized that the wave particle duality would not be such a problem if it were not for all the structure of matter. A wave cannot be detected with another wave alone, matter must be involved. When a wave is emitted, it is not a particle until it interacts with the 'certainty' of a test particle.

I realize I have been soley taking aim at the wave particle duality without realizing it. I will have difficulty talking on the forums, my beliefs let me see no difference between the wave and a sea of overlapping particles, I can even account for electrostatics and gravity. What a creative mind will do to simplifiy... Sorry, this forum might not the right place to explore my question. I'm straightened out none the less, thank you. I accept the physics.

 

[rchase]

Has a background of very densely interfered photons been ever mathematically substituted for the waves? I presume this might align with concepts like loop gravity etc... Are there any theories which define vacuum fluctuations as a sea of interfering photons?

 

[rchase]

if there were as many Ganges rivers as the sand-grains of the Ganges, would the sand-grains of them all be many? (Good night.)

 

[Rap]

Has a background of very densely interfered photons been ever mathematically substituted for the waves? I presume this might align with concepts like loop gravity etc... Are there any theories which define vacuum fluctuations as a sea of interfering photons?

You are mixing up waves and photons. The wave gives you the probability of finding a photon. If the wave is zero, THERE ARE NO PHOTONS. Photons do not interfere, waves interfere. There is no such thing as an interfered photon, its a contradiction in terms.

If you add two coherent beams together that are 180 degrees out of phase, nothing comes out, no photons, no energy, no momentum, nothing.

If the two beams are separate before they are added, their individual energy, momentum, photons, whatever are redirected elsewhere. Energy and momentum are conserved.

 

[zonde]

How does the absorbing medium determine whether the photon is a destructively or constructively interfered photon?

Previous photons that have reached absorbing medium before particular photon create the state in medium that can interfere (or resonate) with particular photon.

Single photon interference can be nicely explained if we assume that photons are simply redistributed. However this approach will require some action at a distance when trying to explain Bell type photon experiments.

I don't understand how. Can you explain that more fully?

This is done using pilot-wave interpretation.
In case of double slit experiment this interpretation says that photons don't take straight paths but instead are deflected toward constructive interference areas.