Double Slit Experiment Explained

[mpc755]

Space is a medium. A photon is a burst of space traveling through space. It is a directed, or pointed, wave.

The Double Slit Experiment (DSE) is easily explained and understood as a photon being a wave traveling through the medium of space.

A picture of a photon that looks like a directed, or pointed, wave can be found at: superstruny.aspweb.cz/images/fyzika/foton.gif

The following analogy doesn't work well for a photon because a photon is described in Quantum Physics as a massless particle that does not occupy space.

So for this analogy we need to use an electron or a small atom. Something that exists as a particle, with mass, as it travels through space.

We will use a boat in water as the analogy for an electron traveling through space.

The boat is traveling through the water at a speed where it is traveling along with its wake (i.e. The wake is traveling out along the front of the boat). As the boat encounters the slits, its wake enters both of them. The wake exits both slits, interacts with itself, and creates interference. As the boat exits the slits, the boat encounters this interference which alters the path it is traveling.

If the boat goes through the slits many times and comes ashore after each passage, the marks it leaves as it comes ashore will make an interference pattern.

The electron, or the small atom, interacts with the interference pattern the wave it is creating in the medium of space in a similar fashion as the boat in water does.

If we were to try and "observe" which slit the boat goes through by placing buoys in the slits, the buoys would destroy the boats wake, turning it into chop. The boat would not create an interference pattern as it comes ashore.

The same is true in the DSE. An attempt to "observe" the experiment turns the wave being created in space into chop and no interference pattern will be created on the screen.

A photon, being a directed wave, interacts with itself, and the mark it makes on the screen is created by the point of the wave.

 

[BenTheMan]

If the boat goes through the slits many times and comes ashore after each passage, the marks it leaves as it comes ashore will make an interference pattern.

No. If the experiment is ideal, and the initial conditions of the boat are the same every time, I don't see why this should be true.

 

[prometheus]

Like rats leaving a sinking ship, the cranks are finding alternatives to physorg now it is offline. This guy doesn't understand the concept of a massless particle so obviously all of physics must be wrong. I have explained what I am about to explain again before but I will do it for the sake of completeness before this thread goes to pseudoscience (and it will, don't you worry).

Space is a medium. A photon is a burst of space traveling through space. It is a directed, or pointed, wave.

Wrong. light can be considered to be a wave in the electromagnetic field. When you quantise this you get photons. A wave of space is a gravitational wave which, when you quantise you get gravitons.

The Double Slit Experiment (DSE) is easily explained and understood as a photon being a wave traveling through the medium of space.

Almost but also wrong. It's easily explained as an electromagnetic wave, unless you've managed to find a way to detect gravitational waves.

A picture of a photon that looks like a directed, or pointed, wave can be found at: superstruny.aspweb.cz/images/fyzika/foton.gif

You're confused between classical electromagnetism and quantum electrodynamics. A photon is a point particle. An electromagnetic wave is a wave. This is a picture of a wave packet.

The following analogy doesn't work well for a photon because a photon is described in Quantum Physics as a massless particle that does not occupy space.

A photon does not have a well defined volume but it still has a position and momentum (within the limits set by the uncertainty principle). There is nothing lacking in this description.

So for this analogy we need to use an electron or a small atom. Something that exists as a particle, with mass, as it travels through space.

You don't understand this at all do you? An electron is just as much a point particle as the photon.

We will use a boat in water as the analogy for an electron traveling through space.

The boat is traveling through the water at a speed where it is traveling along with its wake (i.e. The wake is traveling out along the front of the boat). As the boat encounters the slits, its wake enters both of them. The wake exits both slits, interacts with itself, and creates interference. As the boat exits the slits, the boat encounters this interference which alters the path it is traveling.

This is an extremely bad model. The electrons in atoms travel in orbits. If electrons were like boats on water they would radiate all their energy and fall into the nucleus - in your model atoms are not stable.

If the boat goes through the slits many times and comes ashore after each passage, the marks it leaves as it comes ashore will make an interference pattern.

So what does the shore correspond to in physical terms?

The electron, or the small atom, interacts with the interference pattern the wave it is creating in the medium of space in a similar fashion as the boat in water does.

This is an extremely complicated and nasty model. It's a lot easier to assume electrons and photons are fields and particles are excitations of the fields. That way the path integral gives you an interference pattern without all this stuff that's put in by hand.

If we were to try and "observe" which slit the boat goes through by placing buoys in the slits, the buoys would destroy the boats wake, turning it into chop. The boat would not create an interference pattern as it comes ashore.

Again, the traditional explanation is far cleaner and works better.

The same is true in the DSE. An attempt to "observe" the experiment turns the wave being created in space into chop and no interference pattern will be created on the screen.

Presumably your model has some predictions that vary from the traditional explanation that will confirm or deny your effort?

A photon, being a directed wave, interacts with itself, and the mark it makes on the screen is created by the point of the wave.

directed wave? point of the wave? You're making up phrases now.

This model (in the loosest sense of the word) is rubbish and has been doing the rounds on physorg for long enough for all the serious physicists there to have thoroughly debunked it. The mods are a lot better here so I suspect this thread will end up in pseudoscience rather quickly. Not a moment too soon in my opinion.

 

[mpc755]

No. If the experiment is ideal, and the initial conditions of the boat are the same every time, I don't see why this should be true.

By ideal, do you mean the boat goes through the same slit exactly the same each and every time? That would imply Which Way, which would not cause an interference pattern to be created.

The boat is going through either slit randomly each and every time so it interacts with the interference created by its displacement wave differently each and every time.

 

[mpc755]

Like rats leaving a sinking ship, the cranks are finding alternatives to physorg now it is offline. This guy doesn't understand the concept of a massless particle so obviously all of physics must be wrong. I have explained what I am about to explain again before but I will do it for the sake of completeness before this thread goes to pseudoscience (and it will, don't you worry).

There is no such thing as a massless particle.

Wrong. light can be considered to be a wave in the electromagnetic field. When you quantise this you get photons. A wave of space is a gravitational wave which, when you quantise you get gravitons.

How does an electromagnetic field exist in a void?

Almost but also wrong. It's easily explained as an electromagnetic wave, unless you've managed to find a way to detect gravitational waves.

You're confused between classical electromagnetism and quantum electrodynamics. A photon is a point particle. An electromagnetic wave is a wave. This is a picture of a wave packet.

A photon does not have a well defined volume but it still has a position and momentum (within the limits set by the uncertainty principle). There is nothing lacking in this description.

You don't understand this at all do you? An electron is just as much a point particle as the photon.

How is a massless point particle different than a pointed wave?

This is an extremely bad model. The electrons in atoms travel in orbits. If electrons were like boats on water they would radiate all their energy and fall into the nucleus - in your model atoms are not stable.

Hasn't the DSE been performed with electrons?

So what does the shore correspond to in physical terms?

This is an extremely complicated and nasty model. It's a lot easier to assume electrons and photons are fields and particles are excitations of the fields. That way the path integral gives you an interference pattern without all this stuff that's put in by hand.

Again, the traditional explanation is far cleaner and works better.

Presumably your model has some predictions that vary from the traditional explanation that will confirm or deny your effort?

No it does not. It is simply a better explanation of observed behaviors.

directed wave? point of the wave? You're making up phrases now.

How is a pointed massless particle that does not occupy space a better definition of a photon than a pointed wave?

This model (in the loosest sense of the word) is rubbish and has been doing the rounds on physorg for long enough for all the serious physicists there to have thoroughly debunked it. The mods are a lot better here so I suspect this thread will end up in pseudoscience rather quickly. Not a moment too soon in my opinion.

I read the rules and they said to post here first.

 

[TimeTraveler]

The universe is the observer and does not exist independently of the observer.

 

[Enmos]

The universe is the observer and does not exist independently of the observer.

lol

 

[prometheus]

There is no such thing as a massless particle.

That is where you are wrong. Massless particles have been proven to exist time and time again. One example:

How does an electromagnetic field exist in a void?

What is a void? Do you mean vacuum? In a vacuum there is no matter but fields of force are perfectly acceptable.

How is a massless point particle different than a pointed wave?

What is a pointed wave? You're making up stuff again. A point particle has no spatial extent whereas a wave of any sort must have some spatial extent.

Hasn't the DSE been performed with electrons?

Yes, which is further evidence for the fundamental objects of nature being fields. Both wavelike and particle like properties are explained this way.

No it does not. It is simply a better explanation of observed behaviors.

That's the point of physics. Observe, hypothesise and explain. Not make up rubbish that doesn't fit with what we observe and declare it explains something. Why don't you go and learn some proper physics instead of spouting garbage on an internet message board? Is it because you haven't got an adequate brain?

How is a pointed massless particle that does not occupy space a better definition of a photon than a pointed wave?

I assume your poor terminology is an attempt to say "point particle" and "point wave" (whatever that is). As I said previously, a particle can be pointlike, but how can a wave be pointlike? It's an impossibility.

I read the rules and they said to post here first.

Doesn't stop what you've posted being crap. Sorry.

 

[prometheus]

smug mode

 

[mpc755]

That is where you are wrong. Massless particles have been proven to exist time and time again. One example:
farm4.static.flickr.com/3039/2870535487_48b483596d_o.jpg

What you see in the picture is the point of the photon wave hitting the screen.

What is a void? Do you mean vacuum? In a vacuum there is no matter but fields of force are perfectly acceptable.

Space exists in the vacuum. Space is a medium.

What is a pointed wave? You're making up stuff again. A point particle has no spatial extent whereas a wave of any sort must have some spatial extent.

A massless pointed particle that has zero-dimensions and does not occupy space is a pointed wave traveling through the medium of space.

A photon is a burst of space traveling through the medium of space.

 

[prometheus]

The fact is that quantum electrodynamics predicts the existence of photons that are point particles, not some made up claptrap like pointed waves, which if your brain is working at all and you think about it for a while you'll convince yourself cannot exist because for something to have wavelike properties it must have a spatial extent.

With QED you can calculate properties of nature that you can measure in experiments and the two agree with an accuracy of 1 in one billion. Until your made up bullshit can do that then I will continue to call it what it is - bullshit. Physicists have squared that particular circle many years ago and have moved on to more interesting and complex problems. It seems you are nothing but a backward ignorant moron with nothing better to do than look for new and more complicated ways to answer questions in a worse way than has already been done.

 

[mpc755]

The fact is that quantum electrodynamics predicts the existence of photons that are point particles, not some made up claptrap like pointed waves, which if your brain is working at all and you think about it for a while you'll convince yourself cannot exist because for something to have wavelike properties it must have a spatial extent.

With QED you can calculate properties of nature that you can measure in experiments and the two agree with an accuracy of 1 in one billion. Until your made up bullshit can do that then I will continue to call it what it is - bullshit. Physicists have squared that particular circle many years ago and have moved on to more interesting and complex problems. It seems you are nothing but a backward ignorant moron with nothing better to do than look for new and more complicated ways to answer questions in a worse way than has already been done.

One of the main reasons for the mistaken belief that photons are particles is because of the photoelectric effect experiment. Einstein concluded that a photon must be a particle because it is able to emit electrons off of the metallic surface.

Later experiments such as the DSE continued with this belief which is why Quantum Physics has had to come up with such a complicated explanation for the DSE observed behaviors.

If Einstein had concluded that the electrons are emitted in the photoelectric effect experiment due to a photon being a burst of space traveling through the medium of space that hits the metallic surface similar to an ocean wave hitting the beach, this explanation would have carried over to the DSE and the DSE would be easily explained and understood.

 

[prometheus]

DSE is easily explained and understood, only not by you unfortunately. I'm not going to wait for you to grow a brain and understand this. If you're really interested buy a book, try the Feynman lectures on physics.

 

[mpc755]

DSE is easily explained and understood, only not by you unfortunately. I'm not going to wait for you to grow a brain and understand this. If you're really interested buy a book, try the Feynman lectures on physics.

One of the main reasons Feynman says that Quantum Physics cannot be understood is due to the behaviors observed in the DSE.

Just because you and Feynman aren't able to easily explain and understand the DSE does not mean all of us have to believe it cannot be understood.

 

[prometheus]

Are you blind? DSE can be easily understood. The fact that you don't is meaningless.

 

[mpc755]

How does a particle go through both slits?

 

[prometheus]

It is often said that a particle must go through both slits for the double slit experiment to work. This is not strictly true. In Quantum field theory particles are not the fundamental objects of the theory - they are excitations of a particular field, for example, photons are nothing more than excitations of the photon field. When you pass a single particle through the double slit experiment you know it's initial position and you measure it's final position, however, you know nothing about it's trajectory - in fact, it does not have a well defined trajectory at all.

I don't expect you to understand this but it has been shown by many people that the path integral formulation of quantum mechanics is completely equivalent to the more familiar Schrödinger formalism. The physical interpretation of the path integral is that you start a particle at a point $$x_i$$ and detect it at a point $$x_f$$. In between the particle does not follow a single path but follows every possible path, each path being weighted with a particular factor - the closer it is to the classical path the more it contributes to the motion. Non classical motion certainly does contribute though, one only has to look at tunnelling to see this.

So in the double slit experiment particles do not do through both slits, or neither slit. You can make no statement about which slit the particle goes through. In quantum mechanics, there is equal probability for the particle to go through each slit so the slits behave like a pair of sources. Even if you only pass a single particle though the experiment, both paths contribute to the measured final position of the particle. That is the explanation of the double slit experiment. If you don't understand it (and I strongly suspect that you won't) then I recommend you read about the path integral (otherwise known as sum over histories).

wiki page (requires knowledge of calculus and wave mechanics)
Wordy description

Summary - if you don't measure the position of the particle, then you cannot say the particle passes through either slit or both. It is simply not defined.

 

[mpc755]

It is often said that a particle must go through both slits for the double slit experiment to work. This is not strictly true. In Quantum field theory particles are not the fundamental objects of the theory - they are excitations of a particular field, for example, photons are nothing more than excitations of the photon field. When you pass a single particle through the double slit experiment you know it's initial position and you measure it's final position, however, you know nothing about it's trajectory - in fact, it does not have a well defined trajectory at all.

I don't expect you to understand this but it has been shown by many people that the path integral formulation of quantum mechanics is completely equivalent to the more familiar Schrödinger formalism. The physical interpretation of the path integral is that you start a particle at a point $$x_i$$ and detect it at a point $$x_f$$. In between the particle does not follow a single path but follows every possible path, each path being weighted with a particular factor - the closer it is to the classical path the more it contributes to the motion. Non classical motion certainly does contribute though, one only has to look at tunnelling to see this.

So in the double slit experiment particles do not do through both slits, or neither slit. You can make no statement about which slit the particle goes through. In quantum mechanics, there is equal probability for the particle to go through each slit so the slits behave like a pair of sources. Even if you only pass a single particle though the experiment, both paths contribute to the measured final position of the particle. That is the explanation of the double slit experiment. If you don't understand it (and I strongly suspect that you won't) then I recommend you read about the path integral (otherwise known as sum over histories).

Summary - if you don't measure the position of the particle, then you cannot say the particle passes through either slit or both. It is simply not defined.

Thanks for the detailed description and for raising the dialog, but I do not see it as a simple explanation. It sounds like much of it is made up just to have a theory that explains the DSE where the photon gets to be a particle.

A photon being a burst of space traveling through the medium of space is a much simpler explanation. Being a burst, it is a wave that goes through both slits. Being a burst, when it encounters the screen in the DSE or the metallic surface in the photoelectric effect experiment it behaves like a particle.

 

[AlphaNumeric]

One of the main reasons Feynman says that Quantum Physics cannot be understood is due to the behaviors observed in the DSE.

Just because you and Feynman aren't able to easily explain and understand the DSE does not mean all of us have to believe it cannot be understood.

Why don't you get yourself a copy of the Feynman lectures. For the price of around £70 (I think) you get one of the greatest compendiums of physics ever written by one of its greatest teachers. Within it you will find that Feynman talks at length about the double slit experiment.

You can also get the audio of his lectures on precisely that, from the lectures he used to give at CalTech. I know a fair amount about quantum mechanics but listening to Feynman explain how he thinks and works on it is an illuminating thing for me even now.

The fact you don't know and don't want to know quantum mechanics doesn't mean it is wrong. I don't know or want to know Welsh but that doesn't mean I think it's pointless and just a collection of incoherent vocal noises.

 

[mpc755]

Why don't you get yourself a copy of the Feynman lectures. For the price of around £70 (I think) you get one of the greatest compendiums of physics ever written by one of its greatest teachers. Within it you will find that Feynman talks at length about the double slit experiment.

You can also get the audio of his lectures on precisely that, from the lectures he used to give at CalTech. I know a fair amount about quantum mechanics but listening to Feynman explain how he thinks and works on it is an illuminating thing for me even now.

The fact you don't know and don't want to know quantum mechanics doesn't mean it is wrong. I don't know or want to know Welsh but that doesn't mean I think it's pointless and just a collection of incoherent vocal noises.

Does Feynman believe "the particle does not follow a single path but follows every possible path"?

If so, I do not see any reason to read up on someone who is wrong about what is occurring in the DSE.