Quantum particles

[Upisoft]

As individual photons, you explain the phenomenon by stating that each photon is always in a combination of two polarization states. Which two states depends upon the direction of the polarizer. Each photon has some probability of making it through each polarizer, depending upon the direction of subsequent polarizers. Thus some percentage of the photons make it through, and some percentage do not.

That is not particle interaction. That's some kind of probability interaction. Explain it with particle interaction, that's what I want to see.

 

[[serious]]

That is not particle interaction. That's some kind of probability interaction. Explain it with particle interaction, that's what I want to see.

single particle interactions can only be described in terms of probability.

 

[Upisoft]

single particle interactions can only be described in terms of probability.

When the particle hits the screen there is no probability there. It hits the screen in definite position. That's called particle like interaction, because "position" is property of particles.

 

[[serious]]

When the particle hits the screen there is no probability there. It hits the screen in definite position. That's called particle like interaction, because "position" is property of particles.

"velocity" is also a property of particles. Position and velocity cannot be simultaneusly known for any object beyond a certain confidence (uncertainty principle). Even that location can't be known until after the particle is no longer there. This is all on top of the fact that the screen isn't what we are talking about at the moment. The polarizing filters are what we are talking about right now.

Let's try another analogy (I have a fondness of analogies for QM topics) we take the sand in the hourglass again, but this time we are using a type of sand that is in thin flat sheets and an hourglass hole that is thin and long so that only sand in the proper orientation (polarity) can make it through. If we put another such hole up perpendicular to the first, it will catch all the remaining sand. If we put up a hole at a 45 degree angle to the other two, we can effectively "bend" the sand polarity so that some of it gets all the way through.

Furthermore, waves also have a position and a velocity subject to the same restrictions.

 

[Chalnoth]

That is not particle interaction. That's some kind of probability interaction. Explain it with particle interaction, that's what I want to see.

You can think of it as the polarizing filter absorbing photons with their polarization axis aligned with the filter's. The interaction is this absorption of individual photons.

 

[Upisoft]

"velocity" is also a property of particles. Position and velocity cannot be simultaneusly known for any object beyond a certain confidence (uncertainty principle). Even that location can't be known until after the particle is no longer there.

I agree that you can't know both with 100% certainty. But you still are able fo find some particle properties like position.

This is all on top of the fact that the screen isn't what we are talking about at the moment. The polarizing filters are what we are talking about right now.

Yes, I know. The screen was an example for particle like interaction.

Let's try another analogy (I have a fondness of analogies for QM topics) we take the sand in the hourglass again, but this time we are using a type of sand that is in thin flat sheets and an hourglass hole that is thin and long so that only sand in the proper orientation (polarity) can make it through.

OK. After first filter in that analogi we have only properly oriented sand particles.

If we put another such hole up perpendicular to the first, it will catch all the remaining sand. If we put up a hole at a 45 degree angle to the other two, we can effectively "bend" the sand polarity so that some of it gets all the way through.

And how would you explain that only N.cos(pi/4) sand particles get through without probability interaction somewere in the process?

Furthermore, waves also have a position and a velocity subject to the same restrictions.

And what exactly is "position" of a wave?

 

[Upisoft]

You can think of it as the polarizing filter absorbing photons with their polarization axis aligned with the filter's. The interaction is this absorption of individual photons.

So if you have only 2 filters and first is aligned along x-axis and second is aligned along y-axis, then one could expect that the combination would absorb only photons aligned with x an y axes. But the fact is that nothing goes through.

 

[Chalnoth]

So if you have only 2 filters and first is aligned along x-axis and second is aligned along y-axis, then one could expect that the combination would absorb only photons aligned with x an y axes. But the fact is that nothing goes through.

The first would absorb all photons with polarizations aligned along the y-axis, leaving only those with polarizations aligned along the x-axis. The second filter would absorb those.

Note that since the photon can only have two polarization states (due to it being a massless spin-1 particle), every photon will be forced into a superposition of polarization along the x-axis and polarization along the y-axis upon interacting with either filter. Thus an unpolarized beam of light (each photon has a random polarization) will end up with half of its photons absorbed as it passes through a polarization filter, and all photons that continue through will have polarization aligned along the axis of the polarizer.

 

[dad]

Yes, they're different. And do have both properties, but do not express them in the same time.

" I think that I can safely say that nobody understands quantum mechanics."
The character of physical law (Cambridge, USA, 1967)

Using only the character of physical law, no wonder no one understands. You guys underline that point well.

 

[lemmings]

Please don’t corrupt this thread by talking about your split, some people do enjoy discussions such as this.

 

[dad]

Please don’t corrupt this thread by talking about your split, some people do enjoy discussions such as this.

" I think that I can safely say that nobody understands quantum mechanics."
The character of physical law (Cambridge, USA, 1967)

Using only the character of physical law, no wonder no one understands. You guys underline that point well.

 

[Upisoft]

Note that since the photon can only have two polarization states (due to it being a massless spin-1 particle), every photon will be forced into a superposition of polarization along the x-axis and polarization along the y-axis upon interacting with either filter. Thus an unpolarized beam of light (each photon has a random polarization) will end up with half of its photons absorbed as it passes through a polarization filter, and all photons that continue through will have polarization aligned along the axis of the polarizer.

You again try to go around the question and add properties that particles do not have. Superposition is property of quantum particles and it is reduced to probability choice upon next interaction. What you do is trying to explain the interaction with quantum properties of the photon. That is correct. Photon is quantum particle and its behavior is what it is.
What you can't understand is what I'm trying to say. Take a marble and hit something with it. You will get particle like interaction. The marble will hit in well defined position. Now try to make interference with the marble. You can't? Well, maybe you can, but it is not measurable. But we're talking about science here. What is not measurable cannot be tested, therefore it is not science. So, even if marbles interfere, that's not science. You say that photons have probability to hit anywhere, but before it hits its wave function collapses and the photon hits a definite dot on the screen. That's Copenhagen interpretation. There are other interpretations, but the fact is they are interpretations, i.e. dogma. You can't test it. You believe it happens this way.
I was talking about facts. And the fact is that you only can measure by interacting. You can't see what the quantum particles do between interactions, therefore you can only apply dogma to that state.

 

[dad]

. You can't see what the quantum particles do between interactions, therefore you can only apply dogma to that state.

Good one.

 

[Chalnoth]

You again try to go around the question and add properties that particles do not have. Superposition is property of quantum particles and it is reduced to probability choice upon next interaction. What you do is trying to explain the interaction with quantum properties of the photon. That is correct. Photon is quantum particle and its behavior is what it is.

Um, okay.

What you can't understand is what I'm trying to say.

Seriously, that chip on your shoulder needs to go.

You say that photons have probability to hit anywhere, but before it hits its wave function collapses and the photon hits a definite dot on the screen. That's Copenhagen interpretation. There are other interpretations, but the fact is they are interpretations, i.e. dogma. You can't test it. You believe it happens this way.

I don't think I ever said anything of the sort.

I was talking about facts. And the fact is that you only can measure by interacting. You can't see what the quantum particles do between interactions, therefore you can only apply dogma to that state.

No. The problem is that you were making claims that particle nature and wave nature couldn't occur at the same time. I demonstrated a situation that can be described by both, and now you go off on this wild tangeant about how we have to be careful not to separate our conclusions from observations. While this is a valid point, I don't see how it is in any way related to the topic at hand.

 

[Upisoft]

No. The problem is that you were making claims that particle nature and wave nature couldn't occur at the same time. I demonstrated a situation that can be described by both, and now you go off on this wild tangeant about how we have to be careful not to separate our conclusions from observations. While this is a valid point, I don't see how it is in any way related to the topic at hand.

Very easy. You have to use probability for your particle case, but that is not particle property.

 

[Chalnoth]

Very easy. You have to use probability for your particle case, but that is not particle property.

It's not a wave property, either. It's a quantum mechanical particle property.

 

[[serious]]

You again try to go around the question and add properties that particles do not have. Superposition is property of quantum particles and it is reduced to probability choice upon next interaction. What you do is trying to explain the interaction with quantum properties of the photon. That is correct. Photon is quantum particle and its behavior is what it is.
What you can't understand is what I'm trying to say. Take a marble and hit something with it. You will get particle like interaction. The marble will hit in well defined position. Now try to make interference with the marble. You can't? Well, maybe you can, but it is not measurable. But we're talking about science here. What is not measurable cannot be tested, therefore it is not science. So, even if marbles interfere, that's not science. You say that photons have probability to hit anywhere, but before it hits its wave function collapses and the photon hits a definite dot on the screen. That's Copenhagen interpretation. There are other interpretations, but the fact is they are interpretations, i.e. dogma. You can't test it. You believe it happens this way.
I was talking about facts. And the fact is that you only can measure by interacting. You can't see what the quantum particles do between interactions, therefore you can only apply dogma to that state.

We can detect and measure interference with alpha particles (helium nuclei) so interference can be detected in "conventional" particles. As such, interference is a property of particles as well.

 

[Upisoft]

It's not a wave property, either. It's a quantum mechanical particle property.

Right. You still can't show both wave like and particle like behaviour in the same interaction.

 

[Upisoft]

We can detect and measure interference with alpha particles (helium nuclei) so interference can be detected in "conventional" particles. As such, interference is a property of particles as well.

You can do it with even hevier nuclei. But cannot do it with large scale objects, for example marble ball..

 

[Chalnoth]

Right. You still can't show both wave like and particle like behaviour in the same interaction.

If you don't think that I showed particle-like behavior in photons with that description, then photons never behave in a particle-like manner.