Hi,

We might have to get a little more specific here and sorry in advance if this starts to sound pedantic, but I think that's the only way to discuss this,

The way I understand it is that Einstein did not actually create anything. He came up with an idea. The idea was to rescue physics from the predominate wave theory of light. All that was known about light at the time was the wave theory of light and it could not explain the photoelectric effect. Einstein realized that if things happened in discrete packets, it would explain why electrons can sometimes be ejected and sometimes not. The interesting thing is for some reason he decided to attribute the light itself as having a discrete behavior. I guess he decided to call it a photon, but I don't think he meant it to mean a little tiny ball entity of some sort, just a quanta, which is a certain QUANTITY of light, NOT an actual particle. I think that was what Einsteins actually meant. Somehow it got promoted to be an actual physical entity like a marble or something, and that probably stuck in because it kind of looks like it works that way. What he really meant I think was the more progressive meaning, that it is just an excitation of a quantum field.

Now what we are looking at here is what happens when light travels, which we believe is a wave at that point, and it continues to be a wave. It might be better to abandon that idea too but we should keep it at least temporarily because it is a better description than a particle at that point. What we are looking at is what happens when it hits something. The energy needed to mess with an electron significantly has to be high enough, and that means the frequency has to be high enough for the given material to actually knock out an electron. Before that however, it can still affect the electron, it just does not have enough energy to eject it.
Now let's say it has enough energy. It has to have that energy BEFORE it hits the surface. Once it hits, the electron gets ejected. But what actually changed here. The energy got absorbed by the electron, that's about it. How does that translate to the light before and/or after being a particle. Why does it have to be a particle. It doesn't, and in QFT it isn't.

This reminds me of a radio wave striking an antenna, but only loosely. The antenna absorbs the wave and that causes electrons to move in the antenna. If the radio wave turned into particles, where did they go?
Do they turn into particles for a zillionth of a nanosecond, then disappear into the electron river. Do they get absorbed by the electrons, and if so why would an electron have to 'absorb' another physical entity.

This seems to make the idea of the photoelectric effect caused by light turning into a particle during an interaction the worst possible argument for light being or becoming a particle.

I guess we could talk about this more, and look at other effects that could make light look like a 'particle'.
Also note this does not stop anyone from thinking of a photon as a particle. It's like thinking of a basketball as being a solid object when really there is air inside; it's an object but not as solid as it seems, yet we still deal with it as a basketball.

I don't have a good enough grasp of the whole QM subject, I know much more about relativity. The subject is full of deep abstractions that I don't really grasp: "quantum field" and "gauge theory" and "higgs field" and "excitation" and "collapse" and "hilbert space" and "spin" and "eigenstate" and so on.

When I do pick up a book and try to make sense of it I find that I need to truly understand these terms and that requires me to learn some seriously unfamiliar math and that's an effort!

 

These physicists model the universe as 24 fields, 12 "matter" fields and 12 "force" fields. Fields come in four flavors: scalar, spinor, vector and tensor - distinguished by "spin" of either 0, 0.5, 1 or 2.

This was found by perusing the web, but I have too many questions...

It really does seem to be a jumbled up mess, lots of odd fields and so on, this is why they seek a unified field theory, to express all of this in terms of a single field.

 

These physicists model the universe as 24 fields, 12 "matter" fields and 12 "force" fields. Fields come in four flavors: scalar, spinor, vector and tensor - distinguished by "spin" of either 0, 0.5, 1 or 2.

And, somehow, the "speed" of information in any and all of these fields is c.

It's almost like the overall complexity is emergent from something far simpler.

Hmmmm.

 

I think I know what you are getting at now. What you are describing is how the photon looks like a wave in both cases.
Maybe you meant to look at what happens when we CLOSE one slit so there is only one slit left.

Well if you would like to try the single slit experiment it's one of the easier ones to reproduce mathematically and sort of fun to play with. I suggest using red green and blue lasers 700mw should do it. then you can play with the map and reproduce using math the pattern you should see and given the knowledge of the formula variables solve for the actual wavelength of your lasers the spectrums of these lasers can vary a fair bit within their range. as for single photons or small photon bursts. you don't see a difference. but you should the patterns don't change and the dot patterns seem to follow the same rule. Therefore light weather by single photon or a continuous source behave the same way and the conclusion being that light is actually both wave and packets of energy.

 

Hi,

We might have to get a little more specific here and sorry in advance if this starts to sound pedantic, but I think that's the only way to discuss this,

The way I understand it is that Einstein did not actually create anything. He came up with an idea. The idea was to rescue physics from the predominate wave theory of light. All that was known about light at the time was the wave theory of light and it could not explain the photoelectric effect. Einstein realized that if things happened in discrete packets, it would explain why electrons can sometimes be ejected and sometimes not. The interesting thing is for some reason he decided to attribute the light itself as having a discrete behavior. I guess he decided to call it a photon, but I don't think he meant it to mean a little tiny ball entity of some sort, just a quanta, which is a certain QUANTITY of light, NOT an actual particle. I think that was what Einsteins actually meant. Somehow it got promoted to be an actual physical entity like a marble or something, and that probably stuck in because it kind of looks like it works that way. What he really meant I think was the more progressive meaning, that it is just an excitation of a quantum field.

Now what we are looking at here is what happens when light travels, which we believe is a wave at that point, and it continues to be a wave. It might be better to abandon that idea too but we should keep it at least temporarily because it is a better description than a particle at that point. What we are looking at is what happens when it hits something. The energy needed to mess with an electron significantly has to be high enough, and that means the frequency has to be high enough for the given material to actually knock out an electron. Before that however, it can still affect the electron, it just does not have enough energy to eject it.
Now let's say it has enough energy. It has to have that energy BEFORE it hits the surface. Once it hits, the electron gets ejected. But what actually changed here. The energy got absorbed by the electron, that's about it. How does that translate to the light before and/or after being a particle. Why does it have to be a particle. It doesn't, and in QFT it isn't.

This reminds me of a radio wave striking an antenna, but only loosely. The antenna absorbs the wave and that causes electrons to move in the antenna. If the radio wave turned into particles, where did they go?
Do they turn into particles for a zillionth of a nanosecond, then disappear into the electron river. Do they get absorbed by the electrons, and if so why would an electron have to 'absorb' another physical entity.

This seems to make the idea of the photoelectric effect caused by light turning into a particle during an interaction the worst possible argument for light being or becoming a particle.

I guess we could talk about this more, and look at other effects that could make light look like a 'particle'.
Also note this does not stop anyone from thinking of a photon as a particle. It's like thinking of a basketball as being a solid object when really there is air inside; it's an object but not as solid as it seems, yet we still deal with it as a basketball.

Ok so you can wrap your head around a light beam being a wave and that is a simpler way to look at it and for most cases it works just fine that way. but no matter what you may think there are things called photons some of those have been traveling since light could escape the particle soup of the birth of the universe. light produced in the center of the sun Gama wave light can take 1 million or more years to escape into the plasma layers and can take more than 100,000 years to escape the sun and head out into the wider universe. photons once off to parts unknown never slow down some have travelled for billions of years. Einstein did far more than you give him credit for. He was instrumental in the birth of quantum physics. He was a different sort of guy looked a physics from a completely different angle. His riding of the light beam mental experiments were laughed at but in the end they were very effective in his coming up with time dealation theories. what he considered spooky action at a distance are now what we call electron or quantum spin the exact subject that this whole thing started at.

 

Ok so you can wrap your head around a light beam being a wave and that is a simpler way to look at it and for most cases it works just fine that way. but no matter what you may think there are things called photons some of those have been traveling since light could escape the particle soup of the birth of the universe. light produced in the center of the sun Gama wave light can take 1 million or more years to escape into the plasma layers and can take more than 100,000 years to escape the sun and head out into the wider universe. photons once off to parts unknown never slow down some have travelled for billions of years. Einstein did far more than you give him credit for. He was instrumental in the birth of quantum physics. He was a different sort of guy looked a physics from a completely different angle. His riding of the light beam mental experiments were laughed at but in the end they were very effective in his coming up with time dealation theories. what he considered spooky action at a distance are now what we call electron or quantum spin the exact subject that this whole thing started at.

Hi there,

I'm sorry but you are misinterpreting the intent of my replies. For example, I am not trying to list everything Einstein did, I am just talking about one thing that he did and where the name 'photon' came from.

Again sorry, but you do not prove something by simply repeating it. For example, if I happen to state that there is no such thing as a photon and you say there is, neither one of us has proved our position. You can then say, "but yeah there is such a thing as a photon", and that would not add to your proof. You have to bring into it something like the photoelectric effect, which has been SAID to prove that light can be a particle. What I did though was counter the reasoning that went into that by mentioning what Einstein actually said about it, but more important brought up some points about WHY we would want to think of light itself as being a particle JUST to prove how the photoelectric effect works.

For example, to see the photoelectric effect we first have to imagine light coming up to some surface. We believe that light acts like a wave before it gets close to the surface. It has to penetrate that surface in order to interact with electrons. So let's define a very small unit of length, which we can call just 'u' (for one unit it is 1u). Ok, so we have the light coming close to the surface, penetrating the surface, then interacting with the electron. The question is, when exactly does the light as a wave turn into a particle, and why would it have to turn into a particle to interact with an electron. Does it want to bump into the electron to knock it out of an atom? That might be the main idea, but when does it decide to turn into a particle in order to do that. Is it:
2u from the surface before it hits,
1u from the surface before it hits,
0u at the surface,
1u below the surface,
2u below the surface,
the instant it hits the electron (which we also have to take to be a particle at that point also I guess),
when does it turn into a particle.
Note what we call a particle is not the same as what we call a quanta.

Maybe this is too deep to discuss here though.

 

Well if you would like to try the single slit experiment it's one of the easier ones to reproduce mathematically and sort of fun to play with. I suggest using red green and blue lasers 700mw should do it. then you can play with the map and reproduce using math the pattern you should see and given the knowledge of the formula variables solve for the actual wavelength of your lasers the spectrums of these lasers can vary a fair bit within their range. as for single photons or small photon bursts. you don't see a difference. but you should the patterns don't change and the dot patterns seem to follow the same rule. Therefore light weather by single photon or a continuous source behave the same way and the conclusion being that light is actually both wave and packets of energy.

Hi,

We don't have to perform experiments all the experiments have been done already we just have to look at the data.

 

I don't have a good enough grasp of the whole QM subject, I know much more about relativity. The subject is full of deep abstractions that I don't really grasp: "quantum field" and "gauge theory" and "higgs field" and "excitation" and "collapse" and "hilbert space" and "spin" and "eigenstate" and so on.

When I do pick up a book and try to make sense of it I find that I need to truly understand these terms and that requires me to learn some seriously unfamiliar math and that's an effort!

Yeah, it does get a little strange.
I was trying to keep it simpler by asking when exactly the light turns into a particle and why it has to turn into a particle when we know waves can transfer energy.
With the photoelectric effect, it seems that somebody wanted to use the pool ball analogy so they could say the target numbered ball was knocked off the table by the cue ball, but too bad we lose the cue ball

I think I have to agree that it may be too deep of a subject to discuss here.

 

Yeah, it does get a little strange.
I was trying to keep it simpler by asking when exactly the light turns into a particle and why it has to turn into a particle when we know waves can transfer energy.
With the photoelectric effect, it seems that somebody wanted to use the pool ball analogy so they could say the target numbered ball was knocked off the table by the cue ball, but too bad we lose the cue ball

I think I have to agree that it may be too deep of a subject to discuss here.

What's a "particle"? what's a "field"? these have no tangible reality, the are defined wholly by mathematics.

 

What's a "particle"? what's a "field"? these have no tangible reality, the are defined wholly by mathematics.

And physics is. ??

 

And physics is. ??

Good question, perhaps an effort to devise models that have predictive value, the better/more it can predict the better the model (aka "theory").

Physics is predicated on the belief the universe is rationally intelligible so whatever that leads to I guess.

 

And physics is. ??

A collection of mathematical models that allow us to make accurate predictions of how the universe behaves.

 

I would complete your statement by saying: "A collection of mathematical models based on observation and experimentation that allow us to make accurate predictions of how the universe behaves."

 

I'm going to watch this, this guy is an authority so I will pay close attention to what he says.

 

Hi W,
This thread is too complicated for me, but I think that quantum computing is where two things happen at the same time, so they aren't travelling at all, just happening
C

 

Hi W,
This thread is too complicated for me, but I think that quantum computing is where two things happen at the same time, so they aren't travelling at all, just happening
C

Good to hear from you. I wish it was that easy.

Traveling is not the main point, causality is. FTL communication causes a breakdown of cause and effect of what's happening. Something happening means a non-static state of events between Spacelike separated observers.
https://phys.libretexts.org/Bookshelves/Relativity/Spacetime_Physics_(Taylor_and_Wheeler)/06:_Regions_of_Spacetime/6.02:_Relation_Between_Events-_Timelike_Spacelike_or_Lightlike

In the Earth - laboratory frame in Figure , Meredith waves her wand (event ) at the same time as Sun explodes (event ). In the right-moving rocket frame Sun explodes after Meredith waves her wand. In the left-moving rocket frame Sun explodes before the wand wave. For a pair of events separated by a spacelike interval, labels "before" and " after" have no invariant meaning: they are frame-dependent. To allow the wand to control Sun would be to scramble cause and effect!

No particle - not even a flash of light - can move between two events connected by a spacelike interval. To do so would require it to cover a distance greater than the time available to cover this distance (space separation greater than time separation). In brief, it would have to travel faster than light. This is alternative evidence that two events separated by a spacelike interval cannot be causally connected: one of them cannot "get at" the other one by any possible signal.



It's intrinsically unintuitive why it happens, so you need to understand the basic math/geometry of why.

 

Good to hear from you. I wish it was that easy.

Traveling is not the main point, causality is. FTL communication causes a breakdown of cause and effect of what's happening. Something happening means a non-static state of events between separated observers.

It's intrinsically unintuitive why it happens, so you need to understand the basic math/geometry of why.

Hi N,
I struggle with maths (here in Uk we do more than one math)

I'm obviously not that good at QC either, but am I correct that there's no actual travelling involved, and the question "is-quantum-communication-faster-than-the-speed-of-light?" is asking about travelling?
C

 

Hi N,
I struggle with maths (here in Uk we do more than one math)

I'm obviously not that good at QC either, but am I correct that there's no actual travelling involved, and the question "is-quantum-communication-faster-than-the-speed-of-light?" is asking about travelling?
C

As @nsaspook explained above, whether two events are "simultaneous" depends on the observer. Prior to Einstein it was assumed, believed that "simultaneous" was universal, absolute but that's not the case.

 

And physics is. ??

One of the many sciences.

Simply put "the study of"

The longer definition involves systematic observation, hypothesis, experimentation etc. also known as the scientific method.

 

Hi N,
I struggle with maths (here in Uk we do more than one math)

I'm obviously not that good at QC either, but am I correct that there's no actual travelling involved, and the question "is-quantum-communication-faster-than-the-speed-of-light?" is asking about travelling?
C

Sure, information is traveling in some form (but not in quantum entanglement), things don't happen by magic.