# Thread: Particle wave duality - was there ever a particle?

1. ## Particle wave duality - was there ever a particle?

After listening to the episode about particle wave dualities, I spent a morning contemplating the issue while cleaning my shop. I had a thought that would seem to eliminate the issue of the particle wave duality, if it were true. This seems simple enough to me, but then again I don't have the physics background necessary to properly dissect my idea. Consequently I thought I'd post it here and see what sort of feedback I receive.

My idea is very simple. There is no particle wave duality because there is no particle. Never was.

My premise is that the universe carries energy in non-quantized packets of waves that we call light. The more energy in a packet the higher it's frequency. Nothing new so far. I'm using the term photon to describe this packet, though that word may not be entirely correct as a photon is considered to be a particle. But it's the best term I have for now.

Where my idea goes is that when the packet of energy encounters some matter there is a possibility of an interaction. When this interaction occurs it consists of the waveform collapsing and trying to transfer all of it's energy in to the matter (atom) that it is interacting with.

The bottom line is that when we we think that we see a photon as a particle that is not what we are seeing at all. We are instead seeing a photon collapse it's wave form, transferring it's energy into an existing particle. The particle is not the photon, it is the atom that it is interacting with.

What happens next depends on the energy state of the atom that the photon interacts with. In most cases the atom is unable to absorb the energy and so it sheds it as another photon. If the atom is able to absorb some energy it may shed a photon with a different frequency. This process takes time which is why light appears to slow down as it passes through different media.

There are some things that I don't have answers for. One of the most specific is why would a photon that is absorbed and re-emitted continue in the same direction of motion as it had been absorbed? This may be a deal breaker.

Anyhow, this idea would eliminate the need for a particle wave duality because there is no particle (there is no spoon!). It would raise questions as to what are the factors that control the probability that a wave might collapse when interacting with a particular atom.

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Originally Posted by eric_marsh
...

My premise is that the universe carries energy in non-quantized packets [emphasis mine- NT] of waves that we call light. ...
That part is demonstrably false.

Nick

3. Originally Posted by Nick Theodorakis
That part is demonstrably false.

Nick
That's something that I was wondering about. Like I said, I don't have a physics background so I'm approaching this from a layman perspective. I didn't know if light frequencies are quantized or not. I don't think that affects the rest of my idea though.

4. Originally Posted by Nick Theodorakis
That part is demonstrably false.
I think what he meant was that you can the amount of energy of energy in a continuum--but the frequency changes. Amounts of energy at the same frequency would be quantized.

5. dcl
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The following responds to the entries that asked questions that I can answer:

eric marsh: My idea is very simple. There is no particle wave duality because there is no particle. Never was.
dcl: Particle-wave duality is real. The same entity under appropriate conditions can be manifested as either a wave or a particle, but not both simultaneously. It's the circumstances that detemine whether the enteity is manifested as a wave packet or as a particle. We have no way of knowing what the entity really is. When light passes through an optical instrument, it behaves like a wave. When the same light falls on a photoelectric cell, it behaves like a stream of particles.

6. Originally Posted by dcl
The following responds to the entries that asked questions that I can answer:

dcl: Particle-wave duality is real. The same entity under appropriate conditions can be manifested as either a wave or a particle, but not both simultaneously. It's the circumstances that detemine whether the enteity is manifested as a wave packet or as a particle. We have no way of knowing what the entity really is. When light passes through an optical instrument, it behaves like a wave. When the same light falls on a photoelectric cell, it behaves like a stream of particles.
Can you provide me with an example of when a photon can be observed as a particle when it is not interacting with another particle?

7. dcl
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An electron acts like a particle when it impinges on any photoactive surface. Such surfaces include photographic film, light-sensitive surfaces in electronic cameras, television pickup tubes, photoelectric cells, and charge-coupled devices (ccd's) used in astronomical telescopes these days instead of the photographic plates that they used to use.

8. Originally Posted by dcl
An electron acts like a particle when it impinges on any photoactive surface. Such surfaces include photographic film, light-sensitive surfaces in electronic cameras, television pickup tubes, photoelectric cells, and charge-coupled devices (ccd's) used in astronomical telescopes these days instead of the photographic plates that they used to use.
In all of those cases the electron or a photon is interacting with a particle. Can a photon be observed to be a particle without interacting with another particle?

9. dcl
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erich marsh, the answer to your question, "Can a photon be observed to be a particle without interacting with another particle?" appears to be, "No." As far as I am aware, it's only during interactions with masses ranging from nucleons to solids that photons can behave like particles. Someone more conversant with quantum mechanics may be able to cite situations in which isolated photons can behave like particles.

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Eric, is this different than the Copenhagen Interpretation, and how so?

Nick

11. dcl
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I do not profess to be knowledgeable on quantum mechanics, but it is my understanding that the Copenhagen interpretation asserts that a measurement MUST be taken in order to learn anything about the state of a quantum system and that the very act of taking the measurement inevitably changes the state of the system. This is the basis of the assertion that is impossible to measure simultaneously both the position and the momentum of any component of a quantum system.

12. Originally Posted by Nick Theodorakis
Eric, is this different than the Copenhagen Interpretation, and how so?

Nick
The Copenhagen Interpretation asserts the existence of a particle after the waveform collapse. I'm questioning if there really is a particle. Yes, we see the waveform collapse at a specific location but did the waveform collapse to a particle or did it simply transfer the energy contained in the waveform to an existing particle?

I don't know the answer to this which is why I posted the question. If we can't observe a waveform collapsing without the collapse being caused by an interaction with a particle how do we know that the photon is a particle and not just a packet of energy carried as a waveform?

From http://en.wikipedia.org/wiki/Copenhagen_interpretation

The Copenhagen interpretation is an interpretation of quantum mechanics, usually understood to state that every particle is described by its wavefunction, which dictates the probability for it to be found in any location following a measurement. Each measurement causes a change in the state of the particle, known as wavefunction collapse.

13. dcl
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The Copenhagen interpretation asserts that the existence of a wave function throughout a region is a measure of the probability that the corresponding particle exists at each point in that region. A measurement of the position of the particle causes the wave function to collapse to zero at every point except the determined position of the particle. The same action causes the motion of the particle to become completely unknown, It's a case of being able to have your cake or eat it but not both!

14. Originally Posted by dcl
The Copenhagen interpretation asserts that the existence of a wave function throughout a region is a measure of the probability that the corresponding particle exists at each point in that region. A measurement of the position of the particle causes the wave function to collapse to zero at every point except the determined position of the particle. The same action causes the motion of the particle to become completely unknown, It's a case of being able to have your cake or eat it but not both!
Hmmmm.... So this is just another way of describing the uncertainty principle?

I decided to look into the question a little further, though not much further. My problem is usually one of having the time or energy to study everything I've got a question about. But I came up with this which seems to be more or less what asked in the first place:

From http://www.play-hookey.com/optics/li..._particle.html

"Actually, photons are not particles in the physical sense that we normally associate with that word. Rather, they consist of discrete bundles of energy which are fixed in magnitude. As a result, each photon takes on some of the characteristics of a physical particle."

I wrote:

"My premise is that the universe carries energy in non-quantized packets of waves that we call light. The more energy in a packet the higher it's frequency. Nothing new so far. I'm using the term photon to describe this packet, though that word may not be entirely correct as a photon is considered to be a particle. But it's the best term I have for now."

Kind of sounds like the same thing.

I also wrote:

"Where my idea goes is that when the packet of energy encounters some matter there is a possibility of an interaction. When this interaction occurs it consists of the waveform collapsing and trying to transfer all of it's energy in to the matter (atom) that it is interacting with. "

From the afore cited page:

"But if we examine a photon as a bundle of energy that simply exhibits some of the characteristics of a physical particle, things begin to make more sense. We know by experiment that a photon can transfer its energy to an electron. The photoelectric effect occurs when photons of sufficient energy actually kick electrons off of the surface being struck by light. But even if a given electron hasn't received enough energy from a photon to free it from its material surface, it can receive enough energy to raise it to a higher orbit around its parent nucleus, or even free it from that nucleus. In such cases, the electron can hold that energy for a period of time before falling back to its usual lower-energy orbit and releasing the energy again. This effect explains many phenomena that we can observe directly."

and

"If the photon has insufficient energy to boost the electron to its next higher possible orbit, the electron cannot hold the energy, and releases it again at once, as a photon that matches the incoming photon. The direction of the released photon depends on the nature of the material substance and the energy of the photon itself, so we get phenomena such as reflection and refraction. "

This seems to be along the same lines of thought that I raised in my first post. So I guess it boils down to "what is a particle?" My original thought was that when light is referred to as a particle what is meant is something matter, as in a little piece of quantum stuff moving really fast in a wave like action. I guess that's might be the source of confusion on my part. I figured that if I said that there is no "stuff" then there is no particle.

Of course play-hooky.com isn't exactly a graduate level paper and probably shouldn't be used as strong reference material but at least it's understandable by those of us without a lot of physics credentials.

So here's what I'm thinking at this point. A photon is not a particle in the common usage of the term. It is, rather, a packet of energy with a wavelength that is inverse to the amount of energy that it contains. The area of the Y & Z axis (with the X axis being the direction of travel) will be smaller with a higher energy photon. Lets say that the photon passes over a region containing some atoms. There is some sort of a probability that the photon will interact with one of those atoms. Suppose that it intersected two atoms simultaneously. It can't interact with both of them can it? I don't think so. Therefore it will interact with one, the other, or neither of them. So what would determine which atom it would interact with? Perhaps the distance from the centerline of the photon's direction of travel would affect the probability of interaction. Then what if the atoms are both the same distance from the centerline of travel? Random probability? (This assumes that the light is not polarized.)

Interesting stuff. I think I'll think about it a little more.
Last edited by eric_marsh; 2008-Aug-06 at 12:13 PM.

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