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futb0l
As you all know there's been a great debate about this topic.
What does the world currently believe? and also Why?
What does the world currently believe? and also Why?
ZapperZ said:Let's get ONE thing straight here - Quantum mechanics does NOT have two separate descriptions of light for when it behaves as a "wave" and when it behaves as "particles". PERIOD! It has one, and only one, consistent description for light, and that's that.
Les Sleeth said:You seem a bit distressed to find out there are still people left who don't know everything about physics. I've thought that maybe PF should have a forum category called "Ask All the Stupid Questions You Want!" for those of us who want to understand, but don't yet and so are bound to have misconceptions.
My stupid question would be, is it possible a photon is oscillating between two conditions, one of which exhibits wave-like behavior, and the other which exhibits particle-like behavior?
ZapperZ said:This type of question appears repeatedly on here and elsewhere. I'm hoping that at the very least, people will pay attention to one or two sentences of what I wrote, so at least the effort I spent would not have been in vain. I have no delusion that this would stop the very same question from popping up again.
ZapperZ said:Secondly, why would a photon "oscillates" between two separate behavior when in QM, there is no separate behavior?
Les Sleeth said:Well, that's what I was asking you, the expert. You yourself said "light behaves as waves in experiments such as the double slit, and behaves as particles when we do things like the photoelectric effect." I'll try to explain what I was thinking.
JohnDubYa said:Particle. No experiment has ever been performed on a photon that demonstrated wave properties to my knowledge.
ZapperZ said:I do not know how else to make this any clearer.
ZapperZ said:You read wrong. What I said was...
"Having said that, the most common explanation for the "wave-particle duality" is that light behaves as waves in experiments such as the double slit, and behaves as particles when we do things like the photoelectric effect."
I said it was a "common explanation" that points to the existence of this so-called duality. But if you read the whole posting from where that came from, I insisted (repeatedly) that there is no such thing as a "duality". How can it when there is only ONE consistent description of light within QM? That was the whole point of my response. I do not know how else to make this any clearer. I have one description of light that can describe ALL the phenomena that it exhibits. So how can I answer your question anymore on the "duality" of light, when there isn't any!.
Les Sleeth said:Well, you do seem to acknowledge behavioral differences (and I am not implying behavioral differences indicate duality), and then seem to contradict yourself in the following two statements:
". . . light behaves as waves in experiments such as the double slit, and behaves as particles when we do things like the photoelectric effect."
". . . why would a photon "oscillates" between two separate behavior when in QM, there is no separate behavior?"
From your point, I lept to wondering what is happening at the quantum level that might make it appear there is duality there. My point was to ask: what is causing the different observed behaviors (i.e., double slit/photoelectric), all falling under the single reality of QM?
I asked if it might be that a photon is continously phasing in and out of particleness; or, looked at from the opposite direction, might it be continuously phasing in and out of waveness. Since we know a photon (and all particles) are intense oscillators, why couldn't a photon be something singular which simply alternates between being more "clumped" and more spread out? Might that not account for the APPEARANCE ( ) of duality? And the reason we see the differences in the double slit experiment and the photoelectric effect is because each of those processes accentuates a particular phase.
ZapperZ said:"phasing in and out" of a photon (at least a real one as opposed to a virtual one) is not described in QM . . .
Les Sleeth said:Actually I said phasing between being more spread out (wave-like) and being more "clumped" (particle-like).
Then please explain interference effects under the assumption that photons are particles.
After you have done so explain the fact that photons have (AFAIK) a spin of 1*.
JohnDubYa said:Single photons do not exhibit interference effects.
reilly said:Zz is correct in that there is a unifying perspective about all of this -- it stems from Quantum Field Theory, which easily allows both a field and a particle perspective. That is, QFT makes it possible to flip back and forth from photon states to field states all with in the same basic fornalism. But the math is highly sophisticated and formidable -- see, for example,Optical Coherence and Quantum Optics, by Mandel and Wolff, everything you wanted to know and didn't want to know about photons.
Think of duality as pragmatic -- sometimes you use your wave "glasses", sometimes your particle "glasses" to understand your measurements--you choose what works best for you. For the layman, focus on the physics, learn the history. Physics is the cumulative effort of many generations of physicists, what the old guys saw and thought is very important to understanding physics today.
reilly said:Zz is correct in that there is a unifying perspective about all of this -- it stems from Quantum Field Theory, which easily allows both a field and a particle perspective. That is, QFT makes it possible to flip back and forth from photon states to field states all with in the same basic fornalism. But the math is highly sophisticated and formidable -- see, for example,Optical Coherence and Quantum Optics, by Mandel and Wolff, everything you wanted to know and didn't want to know about photons.
Les Sleeth said:I realize the burden is on me to make myself clear, and I haven't yet (and believe me, I am completely ready to accept that my idea is 100% wrong as soon as I can tell someone is responding to what I am saying).
I do NOT mean a photon "can" flip back and forth between "perspectives." I emphasize your use of the word "can" because what I am suggesting is that a photon must flip back and forth because that is part of what defines what it is. I am saying, or asking: what if a photon is rapidly (really rapidly) shifting between opening out and tightening back up? In fact, shifting so fast that both phases exist simultaneously, and would appear to exist simultaneously if we could observe the phases at the same time. That leads to the second concept of observation, which is that the methods we employ expose either one side of the shift or the other, depending on the method we use. I've included two little diagrams to explain my meaning.
In Diagram 1 is a platform which swings from side to side. The top figure represents when the platform is at the far left extreme, and the bottom figure represents when the platform is at the right extreme.
Diagram 2 represents what should happen if we could get the platform to oscillate between the two extremes fast enough. At some critical speed, the platform would appear to exist simultaneously in both the left and right positions, differentiating into left and right "phases."
That analogy might demonstrate simultaneity and phase differentiation, but it isn't the best analogy for explaining what happens on the human observational end (because the two phases are so similar). But say I had a device that only registered things angled to the left of it, and another device which only measured things angled to the right of it. Whichever one I rely on one to observe, automatically prevents me from seeing the other phase, which is still there counterbalancing its sister phase whether we can observe it or not. So, it isn't a matter of a photon "can" flip, or a photon's flip in "perspective."
ZapperZ said:I'm sorry, but I was under the impresson that you were asking for what we already know about photons and how they are described within the theory that works. I did not realize you were trying to offer an EXPLANATION for why they work, which isn't contained in the theory. I thought such things are usually confined to the Theory Development section and I typically do not wish to entertain such querries.
rayjohn01 said:I agree with Zapper that QM provides a single description , but I do not think that it provides a 'seeable' one , and I think an experiment often emphasizes one characteristic over another.
terrabyte said:last thing i read about photons was they they are "particles" in the basic sense, and they exhibit wave properties because if their unique property of being first state energy.
their diffraction is not actually bending of the light, but rather the light hitting something and transfering its energy to it, and in turn that something jumps back down from its excited state and re-emits the light in a direction seen as "bent"
frequency and wavelength of particle light can be defined as particles per second.
forgot where the heck i read this at though, but it seems sound
terrabyte said:in the model i described, diffraction is wholly based upon photon-energy interaction with the material you make the slit out of.
with a large slit, more light goes through that doesn't contact the material, and generally drowns out the effects of the light that does hit the material edges. as the slit gets smaller, that light that doesn't contact the edges of the material gets smaller, and the difracted light (photons hitting the edges of the material) becomes more apparant.
as described, the photons hit the edges and get absorbed kicking the atoms up to a higher energy state. the atoms then drop back to their natural state and emit the light in a random direction. this randomness is the dispersion we witness from the ultra thin slit.
i'm thinking that this also ties somehow into your "uncertainty principle"
terrabyte said:i said the diffraction does occur regardless of the slit size, but with a larger size the volume of light that doesn't come in contact with the slit sides is greater and that light drowns out the pattern so it's hard to detect it.|
terrabyte said:this page gets into it a little as far as photon-atom interactions
Removed link
Integral
gonna have to hunt down more stuff later, must... sleep
jatin9_99 said:light has both the nature of wave and particle, as according to de broglie he showed his work as folllowing
Einstein said e=mc^2 so this is particle nature
and max Planck said h=wc where w is wavelenght and c speed of light
=> c=h/w
and e=mc^2
=> e=m(h/w)^2
this proves that light have wave nature too