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Are Particles Theoretically Tangible?
#21
RE: Are Particles Theoretically Tangible?
(March 25, 2022 at 5:02 pm)Ranjr Wrote: Thread read, but I'm still wondering, has wave-particle duality been fully explained?   Popcorn

Has *anything* been fully explained? I think of the wave-particle duality as a raw fact.
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#22
RE: Are Particles Theoretically Tangible?
(March 26, 2022 at 9:13 pm)polymath257 Wrote:
(March 25, 2022 at 5:02 pm)Ranjr Wrote: Thread read, but I'm still wondering, has wave-particle duality been fully explained?   Popcorn

Has *anything* been fully explained? I think of the wave-particle duality as a raw fact.

I’ve read that particles can behave like particles and can also behave like waves. How literally can this be taken though? Does this essentially mean what we call particles transform between particle states and wave states on the quantum level? Are particles becoming waves, literally, which then are waves that become particles again?
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#23
RE: Are Particles Theoretically Tangible?
(March 27, 2022 at 12:32 am)JairCrawford Wrote:
(March 26, 2022 at 9:13 pm)polymath257 Wrote: Has *anything* been fully explained? I think of the wave-particle duality as a raw fact.

I’ve read that particles can behave like particles and can also behave like waves. How literally can this be taken though? Does this essentially mean what we call particles transform between particle states and wave states on the quantum level? Are particles becoming waves, literally, which then are waves that become particles again?

Yes! Some exotic experiments demonstrate this, using light from distant stars.
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#24
RE: Are Particles Theoretically Tangible?
(March 26, 2022 at 9:13 pm)polymath257 Wrote:
(March 25, 2022 at 5:02 pm)Ranjr Wrote: Thread read, but I'm still wondering, has wave-particle duality been fully explained?   Popcorn

Has *anything* been fully explained? I think of the wave-particle duality as a raw fact.

I remember in high school puzzling over this when we had to read about it in our textbooks. I kept asking her how something could be both a wave and a particle. Her short answer was: "it just is."

Raw fact or no, I have sought an "explanation" of the phenomenon via pop sci articles and YouTube channels.

What made the most sense to me (as a layman) is that the wave is an expression of the potentiality of the "particle's" location. When you narrow things down (ie. measure it) that measurement is going to mark that particle at a specific place and time and thus, when measured, the phenomenon is more particle-like.

I'm aware that's a pretty basic and bastardized explanation. That might help Jair with his befuddlement over QM, if that indeed is a correct way of seeing QM.

A LOOOOONG time ago, Iggy posted this video about an experiment where photons were sent through a series of filters. The experiment showed that the uncertainty principle isn't a "measurement" problem. It's a "locality problem." I doubt he'd remember it or I'd ask him to repost it here.

(aw fuck it) on the off chance @ignoramus ... do you remember that video? It was like 4 years ago, so no worries if you don't.


edit:

(I actually found it! So nevermind, Iggy.)



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#25
RE: Are Particles Theoretically Tangible?
(March 27, 2022 at 4:42 am)vulcanlogician Wrote:
(March 26, 2022 at 9:13 pm)polymath257 Wrote: Has *anything* been fully explained? I think of the wave-particle duality as a raw fact.

I remember in high school puzzling over this when we had to read about it in our textbooks. I kept asking her how something could be both a wave and a particle. Her short answer was: "it just is."

Raw fact or no, I have sought an "explanation" of the phenomenon via pop sci articles and YouTube channels.

What made the most sense to me (as a layman) is that the wave is an expression of the potentiality of the "particle's" location. When you narrow things down (ie. measure it) that measurement is going to mark that particle at a specific place and time and thus, when measured, the phenomenon is more particle-like.

I'm aware that's a pretty basic and bastardized explanation. That might help Jair with his befuddlement over QM, if that indeed is a correct way of seeing QM.

A LOOOOONG time ago, Iggy posted this video about an experiment where photons were sent through a series of filters. The experiment showed that the uncertainty principle isn't a "measurement" problem. It's a "locality problem." I doubt he'd remember it or I'd ask him to repost it here.

(aw fuck it) on the off chance @ignoramus ... do you remember that video? It was like 4 years ago, so no worries if you don't.


edit:

(I actually found it! So nevermind, Iggy.)




This is a good way to look at it. Usually, polarization is regarded as a wave phenomenon, but when you realize that it is all about the photons (particles), you start to see the basic quantum strangeness.

But, yes, the wave is a probability wave (well, close--it is a bit more complicated than that) for detection of various 'particle' properties (such as location, momentum, energy, spin, etc).

(March 27, 2022 at 12:32 am)JairCrawford Wrote:
(March 26, 2022 at 9:13 pm)polymath257 Wrote: Has *anything* been fully explained? I think of the wave-particle duality as a raw fact.

I’ve read that particles can behave like particles and can also behave like waves. How literally can this be taken though? Does this essentially mean what we call particles transform between particle states and wave states on the quantum level? Are particles becoming waves, literally, which then are waves that become particles again?

No, it is not a transformation. Our measurement determines what sort of properties we will detect.

The closest intuition is that the wave gives the probability of detecting a particle.

The remarkable thing is that *all* quantum sized 'things' have this dual property, whether they be electrons, photons, neutrinos, quarks, protons, neutrons, or even atoms (although the wavelengths are much shorter). All are 'probability waves of detecting a particle'.

An electron microscope is based on the wave properties of electrons, for example.
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#26
RE: Are Particles Theoretically Tangible?
(March 27, 2022 at 8:12 am)polymath257 Wrote: No, it is not a transformation. Our measurement determines what sort of properties we will detect.

I was thinking of the delayed choice experiments:

Wikipedia -- Wheeler's delayed-choice experiment
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#27
RE: Are Particles Theoretically Tangible?
(March 27, 2022 at 8:12 am)polymath257 Wrote:
(March 27, 2022 at 4:42 am)vulcanlogician Wrote: I remember in high school puzzling over this when we had to read about it in our textbooks. I kept asking her how something could be both a wave and a particle. Her short answer was: "it just is."

Raw fact or no, I have sought an "explanation" of the phenomenon via pop sci articles and YouTube channels.

What made the most sense to me (as a layman) is that the wave is an expression of the potentiality of the "particle's" location. When you narrow things down (ie. measure it) that measurement is going to mark that particle at a specific place and time and thus, when measured, the phenomenon is more particle-like.

I'm aware that's a pretty basic and bastardized explanation. That might help Jair with his befuddlement over QM, if that indeed is a correct way of seeing QM.

A LOOOOONG time ago, Iggy posted this video about an experiment where photons were sent through a series of filters. The experiment showed that the uncertainty principle isn't a "measurement" problem. It's a "locality problem." I doubt he'd remember it or I'd ask him to repost it here.

(aw fuck it) on the off chance @ignoramus ... do you remember that video? It was like 4 years ago, so no worries if you don't.


edit:

(I actually found it! So nevermind, Iggy.)




This is a good way to look at it. Usually, polarization is regarded as a wave phenomenon, but when you realize that it is all about the photons (particles), you start to see the basic quantum strangeness.

But, yes, the wave is a probability wave (well, close--it is a bit more complicated than that) for detection of various 'particle' properties (such as location, momentum, energy, spin, etc).

(March 27, 2022 at 12:32 am)JairCrawford Wrote: I’ve read that particles can behave like particles and can also behave like waves. How literally can this be taken though? Does this essentially mean what we call particles transform between particle states and wave states on the quantum level? Are particles becoming waves, literally, which then are waves that become particles again?

No, it is not a transformation. Our measurement determines what sort of properties we will detect.

The closest intuition is that the wave gives the probability of detecting a particle.

The remarkable thing is that *all* quantum sized 'things' have this dual property, whether they be electrons, photons, neutrinos, quarks, protons, neutrons, or even atoms (although the wavelengths are much shorter). All are 'probability waves of detecting a particle'.

An electron microscope is based on the wave properties of electrons, for example.

So when a particle behaves like a wave, it’s simply moving so quickly that we can’t detect it at a specific given point?

Does this mean that it’s theoretically possible that things we once thought were waves (like light) might actually be composed of super fast moving particles? If this can be true of light can it be true of other forms of energy?
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#28
RE: Are Particles Theoretically Tangible?
(March 27, 2022 at 2:00 pm)JairCrawford Wrote: So when a particle behaves like a wave, it’s simply moving so quickly that we can’t detect it at a specific given point?

Does this mean that it’s theoretically possible that things we once thought were waves (like light) might actually be composed of super fast moving particles? If this can be true of light can it be true of other forms of energy?

A fundamental aspect to reality is the Uncertainty Principle, which is not merely a hunch that physicists have that may or may not be overcome someday, but a theoretical limit on that which can, in principle, be measured to an arbitrary level of precision no matter the sophistication of the measuring apparatus.

Finally, as discussed elsewhere on this board, these are scientific models of how Nature works, and scientists test, refine and retest these models to ever and ever greater levels of precision, trying to develop even better models.

Once again, the burden of proof is on someone to come up with a better model that makes testable predictions that are more precise than those of existing models, and, especially, that lead to new discoveries. Scientists who do such things sometimes win Nobel Prizes.
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#29
RE: Are Particles Theoretically Tangible?
(March 27, 2022 at 2:00 pm)JairCrawford Wrote:
(March 27, 2022 at 8:12 am)polymath257 Wrote: This is a good way to look at it. Usually, polarization is regarded as a wave phenomenon, but when you realize that it is all about the photons (particles), you start to see the basic quantum strangeness.

But, yes, the wave is a probability wave (well, close--it is a bit more complicated than that) for detection of various 'particle' properties (such as location, momentum, energy, spin, etc).


No, it is not a transformation. Our measurement determines what sort of properties we will detect.

The closest intuition is that the wave gives the probability of detecting a particle.

The remarkable thing is that *all* quantum sized 'things' have this dual property, whether they be electrons, photons, neutrinos, quarks, protons, neutrons, or even atoms (although the wavelengths are much shorter). All are 'probability waves of detecting a particle'.

An electron microscope is based on the wave properties of electrons, for example.

So when a particle behaves like a wave, it’s simply moving so quickly that we can’t detect it at a specific given point?

Does this mean that it’s theoretically possible that things we once thought were waves (like light) might actually be composed of super fast moving particles? If this can be true of light can it be true of other forms of energy?

No, it doesn't mean that. This is true of even 'slow moving' particles (those with low momentum).

it means that particles do not have *definite positions*. In your idea of 'fast moving particles', those particles would still have definite positions at each time. But this is *precisely* where quantum mechanics gets strange.

The wave gives the *probability* of detecting a particle in the available positions. Which position will actually be detected is *completely random* subject to that probability distribution.

The particle simply does not *have* a well-defined position (or momentum, or various other properties).

(March 27, 2022 at 9:47 am)Jehanne Wrote:
(March 27, 2022 at 8:12 am)polymath257 Wrote: No, it is not a transformation. Our measurement determines what sort of properties we will detect.

I was thinking of the delayed choice experiments:

Wikipedia -- Wheeler's delayed-choice experiment

The biggest problem, frankly, with interpreting quantum mechanics is that people try to understand it with classical concepts. But that is getting things *exactly backward*. We understand the *old* concepts in terms of the *new*, not the new in terms of the old.

In the delayed choice or even quantum eraser experiments, the wave function *always* determines the probabilities for the results. if you set things up so that *another* interaction occurs, you have to follow the wave function through that interaction. And, in cases where interference happens, you can end up with results that look very strange from a classical perspective even if the result is a simple consequence of the quantum description.

There is no 'delayed choice' on whether a particle 'goes through which slit'. The *wave* always goes through both slits. The interaction *after* the slits affects the end result and determines if there is an interference pattern or not.
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#30
RE: Are Particles Theoretically Tangible?
The way I like to think of it, is that every particle is both countable (a single item) and a wave.

Sometimes the wave can impart its energy to a very specific position, and we think of it as a particle during that interaction, but that is simply a change in the wavefunction due to an interaction that localizes its position.
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