Double Slit Experiment Explained

I'll repeat, we aren't going to wait for you to grow a brain. The fact is that you are wrong about photons. You not understanding the explanation does not mean that it isn't right. Feynman was one of the greatest physicists of the 20th century and you are a nobody. Who do you think people should trust?

 

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Considering he's one of the people who pioneered the notion of a path integral, where you sum over all possible paths a quantum object can take to get from A to B, which is the corner stone of field theory, it would appear he does.

Then there's the diagrams which bear his name. If you want to compute say two electrons bouncing off one another you have to consider ALL possible ways they can do this. First you consider them exchanging a photon only. That's how non-relativistic quantum mechanics says happen. But then you add quantum corrections, infinitely many of them. The first quantum correction is that the photon turns into a pair of charged particles (say an electron and a positron), they then recombine into a photon which hits the electron. Then you consider the next quantum corrections, that the pair of electrons created from the photon exchange a photon between themselves. Then you consider things like that photon turning into a virtual pair and then back into a photon.

You consider EVERY possible way the photon can get from the first electron to the second. Every possible circumstance, every possible energies and momenta the virtual pairs can have. Everything.

And it's that work which got Feynman a Physics Nobel Prize. And also QED is the more precise physics we have ever developed.

As Prom says, who should we listen to, someone who was considered one of the greatest physicists ever, who won a Nobel Prize, was renouned for his insight into the concepts of physics and whose textbooks give a complete description of the DSE, both qualitatively and quantitatively, which has been tested a great many times by a great many people, or should we listen to you, someone who doesn't know how science works, doesn't know any quantum mechanics or relativity but dismisses both of them and who doesn't realise if you're going to claim "I've explained gravity!" (as you did on PhysOrg) it means you must be able to accurately model physical systems using your work. Given I asked you many times to do that and you couldn't, you are lying when you make the afore mentioned claim.

Do you know any vector calculus, linear algebra or group theory? They are the backbone of all kinds of physics. If you don't know them you can never develop a viable model of gravity or understand the precise reasons QM explains the DSE in both a conceptual and quantitative way.

You make the mistake so many people do, mostly cranks, of thinking that because you find a concept doesn't square with your intuition it must be wrong. Your intuition is the result of being familiar with patterns of everyday life. Given quantum mechanics isn't the kind of thing which shows up in everyday life normally and you ardently avoid reading up on quantum mechanics you don't grasp it's concepts. And a 30 second Wikipedia read isn't enough. Those of us who do have quantum mechanics coming up in our lives each and every day see how QM explains the DSE.

 

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Just because he was brilliant doesn't mean he couldn't have been wrong.

You accept that the photon, as a particle, follows an infinite number of paths because a brilliant man told you to believe it.

If you were to think for yourself, you would realize a photon defined as a burst of space traveling through the medium of space is a much better explanation of what is occurring in the DSE.

It shouldn't matter if a nobody, or a genius, is putting forth a theory.

The theory that explains the observed behavior better will hopefully, eventually, win out.

 

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Or you could say a photon is a burst of space traveling through the medium of space and not have to deal with things like path integral.

You do realize all of the complexities that Feynman had to invent and you choose to believe is because QM insists a photon is a particle.

What would happen if you paused for a second and choose to consider a photon as a burst of space traveling through the medium of space?

You would no longer have to consider a photon traveling in an infinite number of possible paths.

 

You have a fundamental misunderstanding that I have pointed out many times both here and on physorg. The quantum theory of electromagnetism casts the photon not as a particle but as a field

 

"In between the particle does not follow a single path but follows every possible path"

A photon as a burst of space traveling through the medium of space is traveling in a single path.

 

That's because the particle is not the fundamental object in the theory, as I've told you more than once.

So how does your photon know about the second slit if it follows only one path through one slit?

 

But it is still required to travel on an infinite number of paths. An outrageous statement considering it is not the fundamental object in the theory.

The photon does not need to know about the second slit. It's a wave with width.

For example, if I have a tank of water with extremely tight rubber sides, I could poke one side of the tank and have the burst of water travel through the water and "poke out" the other side.

If there are slits in the path of the burst of water, as long as the slits are not very far apart, the burst of water will travel through both slits and create interference as it exits the slits. The direction the burst is traveling will be affected by this interference, but it will still "poke out" the other side of the tank.

By definition, a burst of water also includes the wave it is creating in the water. The slits do not have to be so close together as to allow what might be considered the "particle" portion of the burst to go through both slits. The slits have to be close enough that the wave associated with the burst of water is able to cause interference as it exits the slits and impact where the burst "pokes out" the side of the tank.

 

You don't get it. Unless it's being measured a particle is not a well defined object at all.

If you send a single photon through the DSE it's probability distribution will be affected by the presence of 2 slits. What you've put, apart from being a bunch of word salad seems to suggest that if you sent a single photon through the DSE it wouldn't care how many slits there are. This is not what we observe. Sending one photon (or electron for that matter) through the DSE you can see the probability distribution depends on the number of slits (in exact agreement with the path integral).

If your interpretation is so good you'll need to do some calculations to show it agrees with what we observe better than QED. I won't hold my breath because QED is the most accurate theory of physics ever. Quantitatively accurate - people calculate things and then go and measure them, not waffle endlessly about the theory until idiots are convinced.

 

If you measure it its a particle, but if you don't measure it it's not a particle. QM nonsense.

It matters how many slits there are because the wave will go through all of the slits and the interference the wave creates as it exits the slits will, obviously, be affected by how many slits the wave went through.

A photon, as a burst of space traveling through space will have a similar distribution.

QED makes things much more complicated than necessary.

 

Lets see a calculation then.

 

Just because I can't do the math doesn't mean the theory isn't better.

And I didn't say the calculations of QED were wrong.

I'm just pointing out that a photon as a burst of space traveling through the medium of space is a much simpler and easier to understand explanation for the observed behaviors witnessed in the DSE.

 

Typical crank response. In reality if your theory cannot be used to calculate things and come up with definite numerical predictions then you're wasting the time of yourself and others. You're not even wrong.

 

Do you even know any QED? QED is actually fantastically elegant. From \(\mathcal{L} = \bar{\psi}(i\gamma^{\mu}D_{\mu}-m)\psi + \frac{1}{2g^{2}}F_{\mu\nu}F^{\mu\nu}\) I can compute any and all electromagnetic phenomena.

How long have I been asking you to provide something quantitative for your claims? And each and every time you've been unable to do so. That one expression from QED allows a physicist to compute measurable things. The fact you don't even realise why you need to give something quantitative shows you have no clue about physics.

 

Just because you have the math, doesn't mean nonsense like a photon is a particle only when it is looked at and for some magical reason interference disappears when a photon is observed, even though you have no explanation for why it disappears, and there is nonsense such as Which Way, and a photon exists in an infinite number of paths, and so on...

Talk about being not even wrong.

You have made up all of this nonsense because you are unable, or unwilling, to comprehend space as a medium.

Yes, you are better at the math than I am. Congratulations.

But a photon being a burst of space traveling through the medium of space explains all of the above as is. There is no need for more.

Pat yourself on the back while you keep your head in the sand.

Just because you can do the math, doesn't mean your explanations of what is happening aren't full of it.

Where would we be today if Einstein, after performing the photoelectric effect experiment had determined that this was evidence that space is a medium and a photon was a burst of space traveling through the medium of space?

If Feynman had taken this concept and applied it to the DSE instead of coming up with more nonsense like path integral formulation, how much further along would QED be?

Keep believing your nonsense as you jump up and down shouting, "I can do the math, I can do the math! Yeah, me!"

 

The way theories of physics work is you propose an idea (like the photon is a quantum field), then you do a bunch of calculations to see what the consequences of your idea are (anomalous magnetic moment of the electron, electron scattering cross sections etc). If your calculations are good you get them published by a peer reviewed journal. Then you get an experimentalist to do an experiment to check your calculations.

Sadly for you, you've got as far as step one and decided that's all that's required. The scientific method has been developed over hundreds of years and you come along and claim it's not necessary? You're even more of an idiot than I thought if you believe this.

Don't worry, I'm sure physorg will be back soon so you can get back to talking crap with other like minded idiots. All it will accomplish is making a person of decidedly small intellect like yourself feel important and smart. Don't forget it is an illusion and that all the while proper science is being done by people with the dedication to put themselves through many years of study and effort. This could be you if you want it to be, but I somehow suspect you'll want to take the easy way rather than the way that will give you real results.

 

In QED, why is it that a photon is only a particle when it is being measured?

In QED, why is it that observing a photon destroys interference?

And you can't say because it is a property of the photon.

My answers:

As a photon is a burst of space traveling through space it appears as a particle whenever it is observed.

For example, in the analogy of a burst of water traveling through the water, if you look at the "nucleus" of the burst, it will always appear to be a particle. That is why it is able to "poke out" the other side of the tank.

Interference is destroyed when observing a photon because the act of observation is destroying the wave being created in space by the burst of space, turning it into chop.

Very easy to explain and understand.

Calculate that.

 

The predictions of QED are precisely what we observe in experiments.

Waffle that.

 

In QED, how is it that a photon is only a particle when it is being measured?

In QED, how is it that observing a photon destroys interference?

 

Your questions are irrelevant because QED has passed every experimental test that has been devised for it. The fact that you don't understand it does not change the fact that it is how the universe works.

Nevertheless, I will try to answer your questions. Firstly, you have to revise what you think a particle is. I suspect you are visualising a billiard ball bouncing around and this is a bad way to think about it. A photon is an excitation of a quantum field - it does not ever have both a well defined position and momentum. The best we can do is assign is a probability to it's position, which is where the interference pattern comes from. The path from the first and second slits interfere so when we measure the position of the particle both slits make a difference.

Which leads me onto question 2. When you observe the particle as it goes through one of the slits the probability of the the particle going through the other slit goes to zero. Hence you only have a single effective source and the diffraction pattern disappears. This has been thoroughly tested and is exactly what we observe, so whether you think it is weird or not, that is the way things work.