The two slit experiment

2 slit
Q: wave or particle
Ur A: when you attend to it
Everything has heat. vibration.
The bands of interference in the experiment are the heat generated from a moving particle.
(You are not seeing the thing, you are seeing the heat it generates.)
You can see the particle splash, if you look closely. Prove me wrong.
 
Xmo1 said:
2 slit
Q: wave or particle
Ur A: when you attend to it
Everything has heat. vibration.
The bands of interference in the experiment are the heat generated from a moving particle.
(You are not seeing the thing, you are seeing the heat it generates.)
You can see the particle splash, if you look closely. Prove me wrong.
Click to expand...
The bands are the result of constructive (crests overlap) and destructive (crests meet troughs) interference of light waves form the two slits.
 
(Q) said:
The bands are the result of constructive (crests overlap) and destructive (crests meet troughs) interference of light waves form the two slits.
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But you say it is the photon. I say it is the wave generated by the movement of the particle, and if you look you will find the particle trace. They are two different things. The particle has no mass, and yet it is a particle moving through space. Professor Lene Hau slowed a photon, where you could plainly see a trail being left by the photon as it moved through the cloud.
 
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Xmo1 said:
But you say it is the photon. I say it is the heat generated by the movement of the particle, and if you look you will find the particle trace. They are two different things. The particle has no mass, and yet it is a particle moving through space.
Click to expand...
Light has energy proportional to its wavelength
 
Xmo1 said:
But you say it is the photon. I say it is the wave generated by the movement of the particle, and if you look you will find the particle trace. They are two different things. The particle has no mass, and yet it is a particle moving through space. Professor Lene Hau slowed a photon, where you could plainly see a trail being left by the photon as it moved through the cloud.
Click to expand...
A photon acts more like a wave when it travels and a particle when it hits something and gets absorbed.

That 'cloud' was a Bose-Einstein Condensate which super cools the photon to absolute zero, thus slowing it down and showing how it can behave like a particle.
 
(Q) said:
A photon acts more like a wave when it travels and a particle when it hits something and gets absorbed.

That 'cloud' was a Bose-Einstein Condensate which super cools the photon to absolute zero, thus slowing it down and showing how it can behave like a particle.
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The wave is a result of particle movement. It is not the particle. It is not the photon. That would be like saying a magnetic field is the magnet. It's not. It's not the magnet acting like a wave. The field and the magnet are distinct things.
 
Xmo1 said:
The wave is a result of particle movement. It is not the particle. It is not the photon. That would be like saying a magnetic field is the magnet. It's not. It's not the magnet acting like a wave. The field and the magnet are distinct things.
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That is not what the quantum theory model says. In QM, entities have both particle-like and wave-like properties, depending on the circumstances, but are neither one thing nor the other. Note that (Q) said what it is "like", rather than what it "is".
 
exchemist said:
That is not what the quantum theory model says. In QM, entities have both particle-like and wave-like properties, depending on the circumstances, but are neither one thing nor the other. Note that (Q) said what it is "like", rather than what it "is".
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exchemist, do you believe it? I have questions, but QM is like that isn't it. The observer affect is baffling to me, but so is quantum entanglement. Guess I'm in good company. To me, particles and the waves caused by their movement are two separate things. Or, as someone said, a photon has energy. That particular energy is different from the waves caused by movement of the particle. (I'm just thinking here.) The energy of the photon would remain near the photon. So what am I seeing; the energy from the particle, the particle itself, or the wave cause by movement? The QM is saying the photon is a shape-shifter, right? If you observe it, it's a particle. If you don't, it's a wave. I never believed in shape-shifters. Maybe I should have been reading different comic books. I'm almost sure the energies have been measured and quantified by now. Time for me to visit the library. Happy Thanksgiving exchemist. Thanks for staying with sciforums.
 
Xmo1 said:
exchemist, do you believe it? I have questions, but QM is like that isn't it. The observer affect is baffling to me, but so is quantum entanglement. Guess I'm in good company. To me, particles and the waves caused by their movement are two separate things. Or, as someone said, a photon has energy. That particular energy is different from the waves caused by movement of the particle. (I'm just thinking here.) The energy of the photon would remain near the photon. So what am I seeing; the energy from the particle, the particle itself, or the wave cause by movement? The QM is saying the photon is a shape-shifter, right? If you observe it, it's a particle. If you don't, it's a wave. I never believed in shape-shifters. Maybe I should have been reading different comic books. I'm almost sure the energies have been measured and quantified by now. Time for me to visit the library. Happy Thanksgiving exchemist. Thanks for staying with sciforums.
Click to expand...
EM waves can certainly be created by the motion of charged particles, e.g. electrons, as in a radio antenna. However it is wrong to think that they are caused by the motion of photons. That is muddling up cause and effect.

Terms from fiction like "shape-shifter" are not helpful in science. Nor is reading comic books, I'm sorry to say. ;)

A photon is a quantum of EM radiation. This concept arose when it was observed that EM radiation can only be absorbed or emitted in discrete chunks, with an amount of energy, E proportional to the frequency, ν of the radiation, according to Planck's relation: E = hν. (h is a constant called Planck's Constant, after the physicist Max Planck.).
 
Question:
Why is there such emphasis on the concept of 2 entangled photons?

When a lightbulb spreads photons all around, are all these photons not entangled?

Photon entanglement refers to a quantum state of two or more photons where they are so deeply linked that the quantum state of each photon cannot be described independently of the state of the others, even when the photons are separated by large distances1.
izakscientific.com

Understanding Photon Entanglement: A Journey through Quantum Optics - izakscientific

Explore the mystery of photon entanglement: the quantum link enabling instant, secure communication across any distance, reshaping our understanding of physics.
izakscientific.com
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Turn the light off and all photons disappear at the same time, no?
 
Write4U said:
Question:
Why is there such emphasis on the concept of 2 entangled photons?

When a lightbulb spreads photons all around, are all these photons not entangled?



Turn the light off and all photons disappear at the same time, no?
Click to expand...
No, I wouldn't think so.

We are receiving light from long dead stars, correct? So, the source has been turned off, but the light still travels.
 
gmilam said:
No, I wouldn't think so.

We are receiving light from long dead stars, correct? So, the source has been turned off, but the light still travels.
Click to expand...
So, how do entangled particles cheat relativity if they cannot travel FTL? Was that problem ever solved?

At SOL, does the temporal dimension of time disappear throughout the spatial universe?
 
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Write4U said:
So, how do entangled particles cheat relativity if they cannot travel FTL? Was that problem ever solved?

At SOL, does the temporal dimension of time disappear throughout the spatial universe?
Click to expand...
The two slit experiment, which is the subject of this thread, is not about entanglement. It is a demonstration of wave/particle duality.

Suggest starting a new thread if you want to talk about entanglement vis a vis relativity.
 
Sorry about that.

I do have another question more to the point.
As time passes the initial uncertainty in position is compounded by the uncertainty in momentum. So, as an electron moves the uncertainty in position increases. This change in uncertainty is represented in Quantum Motion by a change in the wave function. As time passes, the wave function spreads out.

Spreading Wave Packets - Kansas State University​

Click to expand...

If the wave function of a single particle is an uncertain probability but not a true physical phenomenon, how can it generate a spread-out physical interference pattern? Or is the interference pattern also a theoretical object? And if it is how can it physically interfere with anything?

A spread-out wave function can physically collapse back into a single particle? That just doesn't sound right.
 
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Write4U said:
Sorry about that.

I do have another question more to the point.


If the wave function of a single particle is an uncertain probability but not a true physical phenomenon, how can it generate a spread-out physical interference pattern? Or is the interference pattern also a theoretical object? And if it is how can it physically interfere with anything?

A spread-out wave function can physically collapse back into a single particle? That just doesn't sound right.
Click to expand...
Your question, which is a good and interesting one, seems to be about dispersion. There is a better explanation, if a bit mathematical, here: https://phys.libretexts.org/Bookshelves/Quantum_Mechanics/Introductory_Quantum_Mechanics_(Fitzpatrick)/02:_Wave-Particle_Duality/2.11:_Evolution_of_Wave-Packets

This points out that light does not disperse with time ( a light pulse maintains its shape as it travels) whereas the wave function of matter particles sch as electrons does spread out by dispersion. This is a manifestation of the uncertainty principle, by which you become progressively more uncertain of the location of a particle as time evolves after the last measurement.

But this is quite a complex area which, as a mere chemist, I do not pretend to be expert in. We need a real physicist to do justice to the topic.
 
Thank you for your kind words and link.
In fact, a plane-wave is usually interpreted as a continuous stream of particles propagating in the same direction as the wave.
Click to expand...

For the record, one more question.
I can understand a wave function spreading (dispersing) over an existing substance.

But in the case of a single photon, what is the substance the wave function is dispersed over?
 
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Write4U said:
Thank you for your kind words and link.


For the record, one more question.
I can understand a wave function spreading (dispersing) over an existing substance.

But in the case of a single photon, what is the substance the wave function is dispersed over?
Click to expand...
No dispersion occurs for an electron in free flight in a vacuum though not, apparently, for a photon under these conditions.

If a substance, or medium, is present there will be electromagnetic interactions with it (whether electron or photon) that completely change what takes place and these interactions will depend on the nature of the medium or substance.
 
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