particle and wave???

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If you read any of the Hawking’s books, there is one thing he mentions quite frequently. Hawkings describes a view of science (the name eludes me) where you accept ideas and concepts if they provide an (so far) infallible mathematical model of something. For instance, do imaginary numbers really exist? Probably not in the same sense that we believe other numbers to exist, but all the same, imaginary numbers make certain calculations easier if not all together possible. This extends, are there 11 dimensions? Who knows, but in some way the mathematical model of the universe in which we have 11 dimensions answers many questions to a very high degree of accuracy, so much so, that predictions about events and phenomenon have been made and found to be correct using a model which assumes the universe has 11 dimensions. Thus, the current belief is the universe has 11 dimensions. Basically, if it looks like ___, smells like ____, than it is ____.

Ok, so what does this have to do with light?
Well in some instances light can be described as a particle, therefore it is a particle. Also, light can be described as a wave so it is a wave.

Anyway, that’s how i wrap my head around it.

Theoretical Phycist have long been known for making instinctive conclusions that later prove to be right. However, for every theory that makes it, hundreds don’t. You (or Hawking) are right about accpeting things the best they come, how else would we progress?

I like to think of it as, “if a tree fell in the woods . . .”

Things only exist because we observe them, and further more how we observe them. To someone who is color blind, grass and dirt are the same color, that’s just how it is. The only reason we know they are wrong is cause other people see colors differently and can explain to the color blind people the difference with models (waves of light and such) that are very accurate and can make predictions.

Physicists with multiple phd’s see the universe as having 11 dimensional super gravity and thus it does. I don’t fully understand it cause i’m 11 dimensional super gravity blind :smiley:

Minor correction: “Einstein’s Nobel Prize was actually for the photoelectric effect, where he showed that light carries energy in discreet amounts, a certain amount per particle.” That should read ‘discrete’.

(Sorry, one of my pet peeves is using one of these words in place of the other. But usually it’s people saying discrete when they mean discrete. This may be the first time I’ve seen the mistake made in the other direction.)

speaking of picky but shouldn’t it be

Heh. When airing a pet peeve, you should be careful not to do the very thing you’re complaining about. In the sentence beginning “But usually…”, you used the same spelling twice.

I think you guys have it right on the wave/particle duality thing ( forget the picky spelling). After pounding my head on the wall a while in college, I decided Light is Light, and it does whatever it wants. Further, we as scientists don’t really know what it is! (People would be surprised how much scientists don’t “really know”). The gist is light is probably not a wave or a particle. However, at different times we can describe it as a wave or a particle. It really does come down to the math we can use to describe, and importantly, predict what light will do. So, don’t say “light IS a wave and a particle” say “light can be described as a wave or as a particle” and I think the world is a little less vexing. Or not.

I see the Field question as being philosofical and the Wave/Particle paradox as a more tangible problem.

Even thought there is nothing wrong in treating light as a wave and a particle as long as it provides correct results, I still regard it as a paradox. The way physicists explain it is by saying an explanation isn’t required and what fun is that?

How can one thing be a lemon and a chair at the same time? This is confusion and rightly so! Even though this is a gross analogy, things are rarely obvious or easy in quantum physics, I still think we need to provide a logical explanation for the duality of light. If you accept an electron’s energy can be both continous and discrete, then there is no paradox at all. But if you can provide an answer that will satisfy the layman I see Nobel prize written on it. Personaly, I think we have not reached that stage yet. There may be a single mathematical model that explains quantum objects as waves and particles and it certainly will require new ideas and concepts. Even our language is imperfect. I was tempted to say “explains particles as waves and particles”. And as I understand it the word quantum comes from Einstein’s work on the photoelectric effect and expresses the idea that energy comes in packets.

IANAP although I have studied the physics of light and all IMHO of course. This was just a somewhat rushed post to express my opinion that there is a valid and important question here.

My point was that saying light maybe described as a particle, means that it is a particle. Or at least if you subscribe to that particular thinking (that i cant remember the name of) that is hawkings subscribes to.

But in the end, it doesn’t really matter. It’s basically the same as arguing the difference between a simile and a metaphor. To some the difference is paramount to others its just an answer on an english final :stuck_out_tongue:

xcalibre said:

I have to disagree with your representation. The universe is going on merrily with or without us around to observe it. My answer to the tree falls question is that it depends on what you mean by the word sound, but that’s a digression.

You are correct if you mean that how you look at it affects what you see, in the sense of wave or particle. This is because in order to look at the EM effect, you must use an EM effect. Thus you are changing what you’re looking at. But “things” exist whether or not they are being observed.

The particle/wave paradox occurs because we’re trying to use mechanical descriptions from the Newtonian, macroscopic (our-sized) world to describe what’s happening at a quantum level.

The fact is, photons are neither waves nor particles. What they are can’t be described in Newtonian mechanics. Photons have qualities like a wave and in the manner of a particle, but they are neither.

Photons and other subatomic ‘particles’ have properties not found in the big world, and so, it would be dead wrong to say that it is either a wave or a particle.

Just as the planetary model of electrons ‘orbiting’ the nucleus had to be put to death (though, bad science teachers still use this outdated model), so too, we need to put to rest the schizophrenic wave/particle model.


“It’s a new, delicious dessert topping!”

“No, it’s a floor wax!”

“You’re both wrong, Glimmer is both a dessert topping and a floor wax!”

I have been accustomed to think (sorry, can’t point what book I got it from) that in the end, what we call “particle” is nothing but the manifestation of some sort of wave in whatever the substrate of reality is (let’s call it space-time, though I fear there must be something more to it; I’m not a physicist).

In essence, matter is a localized disturbance in this medium. Hence this medium could not be explained as matter. It is of a more fundamental nature. Waves in this medium are NOT akin to waves in matter (sound, etc).
The fact is, humans --and human-designed apparatus-- grasp matter by the type of behaviour it exerts on their senses. As such, “particle” describes not a real thing, but the perception we have of that “wave”.

This explains why light (or other quantum objects) “behave” as waves or particles according to the experiments. This also solves the question of duality: particle and wave are the same thing.

I know, I know, experiments to prove that light is a particle seem to infer that it cannot be a wave. And vice versa. I think that it comes from the wrong paradigm, in which particle behaviour and wave behaviour are seen as contradictory. So maybe it is best to use another term, and reserve “wave” and “particle” for specific observable behaviour.

I loved the analogy with “father” and “son”. A man cannot be at the same time “my” father and “my” son. But he can easily be both “a” father and “a” son. Same with the experimenter: in “my” experiment, light cannot be both. But no problem when we step back.

But the “wave” theory cannot explain the photoelectric effect or the “ultraviolet catastrophe” paradox, and this “substrate” sounds just like the old “ether” with a new name. And if you say, “Yes, but it’s different from all other waves,” then you might as well say it isn’t a wave.

Certain equations are true. Under certain extreme conditions, these equations give results resembling the results for a classic wave or a classic particle. But the truth isn’t in either of those images: it’s in the equations.

The problem is if I was smart enough to present you with a radical new experiment, you might not be able to predict which form of light would manifest itself. This is overly vague but am I wrong here? Maybe this is a huge stretch and there is nothing out there that new about light…

For example, to give you a mental picture, imagine you master both mathematical models very well, both discrete and continuous without ever having performed an experiment, just math not physics so to speak. Then I say I will bombard a photon detector with photons. Will you be able to predict if you hear a single short click or a long click with a range of different intensities?

And if you can’t say why or when one or other is correct, this doesn’t bother you?

Even if we come up with something new that does not provide results that could not be obtained before, it is an important progress nevertheless. I think saying light can be dual but not at the same time is ignoring the why of it; there is certainly a third state but whatever the math says isn’t it. Sometimes we discard roots of polynomials because they don’t make sense for the given problem. No, forget that, bad example, upon further thought it is just a bad definition of the domain of the function. Anyway, it is surely very difficult to provide an explanation to something so unfamiliar to us but important nevertheless. Just because our math works does not mean there isn’t a better way to study the problem. It is important not to object to the results obtained just because the method does not make sense to us but it is also important to question why that is. The paradox is caused by a gap in our understanding of the nature of light, methinks. Maybe a theoretical breakthrough can be achieved that will make the two models co-exist peacefully.

I was addressing John W. Kennedy but I’d like someone more knowledgeable than me to weight in on this…

:slight_smile: Told you I wasn’t a physicist…
I did not mean the wave theory. OK my expression was poor. Particle is not wave; particle and wave are peculiar forms of “it”, which I shouldn’t have called a wave.

So yes, it isn’t a wave, and yes, it needs a new name, but no, it isn’t ether.
“Ether” is supposedly some kind of matter in space. It is to be interpreted at the level of matter, space and time.

I meant some more fundamental level of explanation.
What I recall is a line of research that, somehow, defines (or explains) matter, space and time as, say, manifestations or properties of something that has not yet received a name. Let’s call it the “real” (more religious-minded would call it the Being).
It is not a field if you mean field in the usual sense. It was more realted (IIRC) to some ‘geometry’ of reality.

As this is a level that is by definition out of our sensitive grasp, it makes sense that our only mode of understanding it would be equations. With no analogic representation.

:frowning: I’m really sorry I cannot remember where I got this from. I assure you it is not a New Age BS, it must have been in a scientific magazine.

There is no “both mathematical models”; there is only one. (Well, there are rival versions, but “wave” and “particle” aren’t part of any of them.) “Wave” and “particle” are both just metaphors that are sometimes useful for visualizing the equations, and sometimes not.

Or, to put it another way, there [i[used to be* a “wave” model and a “particle” model, but for nearly a hundred years it’s been known that both were wrong. It’s the blind men and the elephant over again.

if you don’t observe the event how do you know it exists?

I don’t really think that this dogmatic approach is helpful.

Is the equation:

F = G m[sub]1[/sub] m[sub]2[/sub] / r[sup]2[/sup]


No, it isn’t. It was long thought to be true, but it turned out to be an approximation. But that doesn’t imply that general relativity is the “ultimate truth”. There’s no reason to assume that GR is anything other than a better approximation.

Same with QED. There’s no reason to believe that it’s anything other than an approximation. And, as you say, it’s just a “model”. It isn’t the “truth”.

Quoth Pedro:

Actually, you can tell. Roughly speaking, it depends on the sizes of things in the experiment. If everything in your experiment is much larger than the wavelength of the light, then it’ll behave like a particle. If there are things in your experiment which are close to the size of the wavelength, then wave behaviour becomes important. It’s a little more complicated than that, of course, but it’s still always possible to determine which it’ll be.

Absolutely. Physical Chemistry and Quantum Chemistry would have been much easier if my professors had thrown some nice analogies like that in there.