Probabilities in QM is like Diffusion in Thermodynamics

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When you square the probability amplitude and it shows there is 20% probability of it occuring, and you perform the experiment 100 times.. you would find exactly 20 times as dictated by the probability. In radioactive decays, individual alpha particle may tunnel at different times but when you average it, it is always half-life. How does each particle know what output to produce to make the total exactly what the probability shows?

It's like the the particles are connected in time. What could have coupled them?

Also the probability in QM is like diffusion in thermodynamics where each particle has different values but the overall total is exactly the macroscopic properties.

Maybe we can think of probabilities in QM in terms of thermodynamics diffusion in time?
In thermodyanamics, the randomness of each particle is due to its being a member of the group, but the whole average out depending on the container. Could QM be related to this diffusion but in time? What is the name of the interpretation that holds this view is there is one already available?
 

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  • #2
Fredrik
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When you square the probability amplitude and it shows there is 20% probability of it occuring, and you perform the experiment 100 times.. you would find exactly 20 times as dictated by the probability.
This is like saying that if you flip a coin and get heads, the result of the next flip will always be tails.

In radioactive decays, individual alpha particle may tunnel at different times but when you average it, it is always half-life. How does each particle know what output to produce to make the total exactly what the probability shows?
They don't.

Also the probability in QM is like diffusion in thermodynamics where each particle has different values but the overall total is exactly the macroscopic properties.

Maybe we can think of probabilities in QM in terms of thermodynamics diffusion in time?
In thermodyanamics, the randomness of each particle is due to its being a member of the group, but the whole average out depending on the container. Could QM be related to this diffusion but in time?
I think this is too speculative for this forum.
 
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This is like saying that if you flip a coin and get heads, the result of the next flip will always be tails.


They don't.


I think this is too speculative for this forum.

This to aid in understanding why the probability occurrences in quantum mechanics is so precise. It is not as speculative as the bizarre concept like Many Worlds and Bohmian Mechanics which many keep discussing in this forum
 
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This is like saying that if you flip a coin and get heads, the result of the next flip will always be tails.

QUOTE]


It's far more than it.

When squaring the amplitude shows there is say 30% of the particle being there. If you perform the experiment 100 times.. you will find it there 30 times exactly. Each experiment is separate in time. They did the particles know to conform to match to prediction?

It's like the double slit experiment where the photon is emitted one particle at a time. After many hours. The interference patterns distribution is there. How did each photon knows to distribute themselves as average. This is more than classical probability because each photon emission occurs separately in time.
 
  • #5
Vanadium 50
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When squaring the amplitude shows there is say 30% of the particle being there. If you perform the experiment 100 times.. you will find it there 30 times exactly.
That wasn't correct the first time you wrote it, and repeating it doesn't make it more correct.
 
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That wasn't correct the first time you wrote it, and repeating it doesn't make it more correct.
I got the idea from Richard Feymann who wrote the book called "The Strange Theory of Light and Matter" where he mentioned:

"For every 100 photons that go straight down toward the glass at 90 degrees, an average of 4 arrive at A and 96 arrive at B. So "partial reflection" in this case means that 4% of the photons are reflected by the front surface of the glass, while the other 96% are transmitted. Already we are in great difficulty: how can light be partly reflected? Each photon ends at A or B - how does the photon "make up its mind" whether it should go to A or B?"

So how does each photon make up its mind whether to go to A or B and conspire to produce exactly 4% reflection??
 
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Feynman said an average. Not exactly.
 
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Feynman said an average. Not exactly.
No problem. So "average". But how do the photons know to go to A or B to make of total of 4% reflection? Feynman didn't answer so I wonder what is the answer. Hope someone can share some insight.
 
  • #9
Fredrik
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Same reason that your coins know that they should land with the "heads" side up approximately 50% of the time if you flip them many times. (There is no reason, other than that there's no significant difference between the two sides of the coin). This doesn't have anything to do with quantum mechanics.
 
  • #10
tom.stoer
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Let's make the double slit experiment even more strange:
- different species (mankind, aliens in the Andromeda galaxy, ...) prepare their setups w/o knowing from each other
- they use slightly different experimental setups (different particles like electrons, photons, atoms, ..., )
- they produce only one single particle for each setup and let it interfere in their experiment
All these guys meet at M87; they agree on one common scale and scale their results; they collect and plot all their individual dots and - find an intererence pattern.

The interesting thing is that each individual particle is interfering with itself; there is no need for the particles to communicae with each other.
 
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Why don't you also ask how a ball knows to fall down when I throw it?

Now that you've read my post you should realize the flow of yours.
 
  • #12
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In Feynman example. Detector A is above the surface that detects the photon reflected,
while detector B detects the photon that goes thru in a glass reflection experiment. We know that in a glass, 4% is reflected. Now Feymann question is how do the photons which enter the glass end up in either side such that 4% are detected at A above the glass. It's as if the photons are part of an essemble. In fact, I think the answer is because the wave function choreograph the behavior of all the photons. Agree?
 
  • #13
qsa
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In Feynman example. Detector A is above the surface that detects the photon reflected,
while detector B detects the photon that goes thru in a glass reflection experiment. We know that in a glass, 4% is reflected. Now Feymann question is how do the photons which enter the glass end up in either side such that 4% are detected at A above the glass. It's as if the photons are part of an essemble. In fact, I think the answer is because the wave function choreograph the behavior of all the photons. Agree?
about right.
 
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I wonder what is the temporal reach of the wave function. For example. If one photon a day is aimed to the glass. In 10 years and after 3650 photons. Would you still have 4% of them being reflected?
 
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Fredrik
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I wonder what is the temporal reach of the wave function. For example. If one photon a day is aimed to the glass. In 10 years and after 3650 photons. Would you still have 4% of them being reflected?
Yes (approximately). This has nothing to do with quantum mechanics. If you flip a coin once a year, after a million years, you will have approximately 500000 heads.
 
  • #16
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Yes (approximately). This has nothing to do with quantum mechanics. If you flip a coin once a year, after a million years, you will have approximately 500000 heads.
What you didn't seem to understand is that the distribution is not 50%-50% but 4%-96%. So you can't use the example of flipping the coin. Do you know that in glass reflections, 4% of the light is reflected? That is why they use anti-reflection coating in a telescope lens, so more light transmission. Now in 10 years.. without QM, you can't explain how the photons can end up 4% reflected unless the wave function dictate them that way.
 
  • #17
Fredrik
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What you didn't seem to understand is that the distribution is not 50%-50% but 4%-96%.
That's irrelevant, but just in case using the same numbers will help you see the point, let's consider a 25-faced die that's rolled once a year. After a million years, you will have had the result "25" roughly 40000 times.

...without QM, you can't explain how the photons can end up 4% reflected...
No, but that's not what you asked. You asked why (approximately) 4% of the total number of photons end up reflected, given that there's a 4% probability of reflection each time. The answer to that has nothing to do with QM.
 

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