Curving light waves

So in a light wave packet the wave portion of the packet will follow the geometric path between the photons. Which in the case of the OP, was curved.

Originally posted by primalfractal
So in a light wave packet the wave portion of the packet will follow the geometric path between the photons. Which in the case of the OP, was curved.

This is your hypothesis? Is this just an idea you have or do you have some evidence or some reason to believe this?

Because as stated before, gravity has been shown to change the path of a photon, but in the absence of such a force, why do you think the wave packet would follow the (curved) geometric path between the photons?

reply to post by Arbitrageur


No, it was a question. If you move the end of the packet while the wave is traveling along it like I am theorizing wouldn't the actual wave curve although the packet remained straight?

Like I said in the first sentance of the OP this is just an idea, please explain how I am wrong. I dont know if it's right. I think I have become to defensive of this in response to all the attacks and went about it from the start with to much pride.

I would like to apologize to you and Astyanax, you have both been gentlepeople, I am truly sorry.

The "I dont know what alpha to omega means" dude is a liar though.

I think the another possibility from your wave packet desciption is a large number of slightly offset waves all going straight, rather than one in the case of the OP. But the idea I had was the effect of changing the wave packet angle. I can do this with your animation and it will prove correct but is it possible other than in theory or high g?

. There are some slight problems, such as the wave packet doesn't really stop at a finite distance from its peak, it also goes on for ever and ever. Does this mean an electron exists at all places in its trajectory?

Is this saying wave packets also have properties of normal waves and can be much longer?

Originally posted by primalfractal
I think the another possibility from your wave packet desciption is a large number of slightly offset waves all going straight, rather than one in the case of the OP. But the idea I had was the effect of changing the wave packet angle. I can do this with your animation and it will prove correct but is it possible other than in theory or high g?

You said you would crucify me if I brought up particles again but I have to do it to respond to this question. If each wave packet is a particle or at least has particle-like properties in addition to wave-like properties, then you have exactly the situation you described in your OP with the bullets. The bullets form a curve, but each bullet is going in a straight line. Similarly, the wave packets would form a curve but each wave packet would be going in a straight line, if no outside force was acting on them after they left the laser. And the reason they form this curve is because as you suggest each one is going at a slightly different angle. Did I misunderstand your post or do we agree?

. There are some slight problems, such as the wave packet doesn't really stop at a finite distance from its peak, it also goes on for ever and ever. Does this mean an electron exists at all places in its trajectory?

Is this saying wave packets also have properties of normal waves and can be much longer?

That's a quantum mechanical interpretation based on probability. The wave function gives you a most likely location, then as you move away from that the probability of the object being elsewhere gets smaller and smaller to the point where it becomes insignificant, but never actually zero. I think this graph is in the same source, isn't it?

abyss.uoregon.edu...

It's not saying the wave function will be longer but rather, that the photon may be in a different location from the most probable position, but on average over lots of photons, they will be in the most probable position.

I realize that I am being ignored. nevertheless ...

op : please please please explain to us this alpha to omega bit. the others haven't mentioned it, but I am sure they have no idea either.


as it seems pretty crucial to your idea, it really deserves a better description.


p.s. I really am not such a bad guy.

reply to post by Arbitrageur

Similarly, the wave packets would form a curve but each wave packet would be going in a straight line

Yes , that is what I was asking, thanks. I wanted a picture of where the waves go. A curving line of multiple wave packets explains what I described but its not completely the point I was trying to make.

I was trying to picture changing the angle of the wave packet while the wave is travelling along it. Would this occur in the OP from gravity, EM, and the Airy effect. So yes the light wave I was describing would still, I think, curve.

If the laser is extruding a wave packet with 1m coherance and you change the angle at 50cm what happens? Thats what I was trying to get to. Does each shift in angle create another wave packet covering the arc with connected wave packets forming a paintbrush curve? This would seem to produce more photons than when left straight.

So when you say the wave packets form a curve is there gaps, or could it be seen as one wave of horizontally connected wave packets?

Planets were shown to curve light.

Do these things actually curve the wave packet or change the angle of the wave packet?

Actually, electromagnetic waves can bend light through an indirect, quantum effect—but to such a tiny degree that we cannot measure it. This quantum effect (called Delbrück scattering) "is a process where, for a short time, the photon disintegrates into an electron and positron pair," says Norbert Dragon, physicist at the Institute for Theoretical Physics in Hanover, Germany. The charged pair interacts with an EM wave and then recombines into the photon with a changed direction. Thus, the EM wave bends the light.

Link

Prof Kishan Dholakia and his research team have developed the concept of moving particles within light beams that follow curves. Previous work in St Andrews and elsewhere has shown that laser beams can trap and guide small particles. But laser beams usually travel in straight lines. The recent discovery uses rather special laser beams that go around corners. This allows them to be used to push small particles from one container to another, for example, as illustrated below.

"Our research has shown that parts of certain light beams do not diffract or spread - they can travel around corners and propel particles round corners. This is a new discovery in the phenomenon of light moving particles."

Professor Dholakia commented, "Physics holds many surprises; our understanding of how light moves and behaves is challenged by such beams and it is exciting to see them move into the interdisciplinary arena - light has thrown us a curve ball!

Another one.

In fact, it is very easy to debunk even our simplest beliefs about
light today. For example, it is currently believed light-waves
somehow "cancel" in "destructive interference" when they meet
out of phase so that the peaks of one wave coincide with the
valleys of another. Yet, a simple experiment crossing 2 light-
beams from common laser pointers shows that it is impossible
for light to vanish into thin air simply because 2 beams are mis-
aligned (out of phase). In fact, it is a violation of the Law Of
Conservation Of Energy to even expect this to occur. Light is
not a mysterious quantum-mechanical wave-particle (duality) entity, but
something very different and much simpler to understand". (Mark McCutcheon

"Much controversy has arisen as to whether light is a particle, as newton claimed o a wave (the same can be said of electricity). There is much evidence in favor of both theories. It is both. Light is expressed by motion. All motion is wave motion. All waves are expressed by fields of equal and opposite pressures of two way motion. The entire volume within wave-fields is filled with the two opposite expressions of motion-the positive expression compresses light into solids and the negative expression expands it into space surrounding solids. All space within wave-fields is curved (due to the curved pressure gradients lenses surrounding the incandescent spherical bodies centering them and the fundamental curved motions of the electrical vortex waves which simulate the ideas of light and space).

Link

If the space curves the wave appears to curve.

reply to post by tgidkp

Alpha and Omega, alpha (α or Α) and omega (ω or Ω), are the first and the last letters of the Greek alphabet

I just meant the beggining and the end of the wave.

reply to post by tgidkp

p.s. I really am not such a bad guy.

Ok, I'll take your word you didnt understand and wern't just trying to bait me.

Originally posted by primalfractal
I was trying to picture changing the angle of the wave packet while the wave is travelling along it. Would this occur in the OP from gravity, EM, and the Airy effect. So yes the light wave I was describing would still, I think, curve.

Yes to gravity, not experimentally confirmed to EM, and no to airy effect, see this article regarding the latter:

Focus: Light Beam with a Curve

As with the Bessel beam’s diffraction-free “propagation,” light doesn’t actually propagate along the curved path.

The photons are all traveling in straight lines but the image does appear curved. Looks can be deceiving.

Regarding gravity, another way physicists look at gravity is that it curves space-time and the photon follows a straight line through curved space time, so from that perspective, it appears to be going straight, but the net effect is that to an outside observer measuring the photon's path and not taking the curvature of space-time into account, the photon does appear to curve. I think you may know as much of the EM curvature as I do if you understand that source you quoted...we have yet to confirm this.

If the laser is extruding a wave packet with 1m coherance and you change the angle at 50cm what happens?Thats what I was trying to get to. Does each shift in angle create another wave packet covering the arc with connected wave packets forming a paintbrush curve? This would seem to produce more photons than when left straight.

This is a good question. Let's start with your gun analogy that needs no quantum mechanics. Moving the gun while firing bullets, and moving the laser pointer while firing photons DOES cause curvature of the path inside the barrels because the barrel or device itself is causing the the curvature (this is a little questionable in most laser devices but you could build a laser device with a long enough barrel where this would happen). So when we say an object won't curve unless acted upon by an outside force, we have identified the outside force, which is the force that's moving the "barrel".

Once the bullet or photon leaves the gun or the laser, if there are no more outside forces acting on them, they will follow a straight line. To address the curvature of the waveform at the exit point,while the laser is moving, you can carry the gun analogy a little further, the bullet now has more uncertainty in the direction of final travel, but it will pick a direction, because the bullet doesn't get any larger. Now, my guess is that the wave packet doesn't get any larger either, but I can't think of any specific experiments to prove this to you, so maybe someday you can devise an experiment and try it. But what I'm basing my expectation are the following principles:

1. We've demonstrated that the energy of photons is quantized, meaning it's not a continuous distribution but only certain finite energy levels can be imparted to the photon. We sort of understand the reasons why this happens, but my point is that moving the laser while the wave is halfway out can't change the energy level of the photon which is quantized to a specific value regardless of the movement.
2. Photons don't have rest mass, but they do have momentum which means they follow the same principle that they won't curve unless acted upon by an outside force. So yes you can curve the photon inside the laser by moving the laser, but once it's left the laser, if there are no more outside forces making it curve, then it won't curve anymore.

It would make an interesting scientific experiment to see where this influence of moving the barrel ends with the photon. In the example you gave where the wave packet is half inside and half outside the laser, I expect that moving the laser can still change the angle. And because of the quantum uncertainty of the photon's position, this might happen even if the wave packet is 60% outside the laser. I would expect an experiment to show that the effect of moving the laser diminishes in accordance with the quantum wave function probability plot in my previous post, as calculated for the photon in this experiment. Maybe this has been tested but if so I'm not familiar with the experiment, and if not, maybe you could be the first to do the experiment? It would be interesting. However once the let's say 0.1m wave packet is perhaps 1.0 m from the laser, the effect of moving the laser may not be zero but is probably insignificant. So from this point on, we could say that the laser can't curve the photon anymore, at least not to a measurable degree, and from then on the photon will travel in a straight line unless an outside force acts upon it.

So when you say the wave packets form a curve is there gaps, or could it be seen as one wave of horizontally connected wave packets?

This is a loaded question and while I know the answer it's not that easy to explain. First, watch this video of individual photons striking the screen in this double slit experiment:

Interference pattern built up photon by photon

What this shows is that if you carefully control the light source, then you can make the gaps between photons pretty big...watch carefully at the beginning of that video. As they increase the exposure time, the gaps get harder and harder to see, and if you fire enough photons, you won't see any gaps at all. Does this mean there aren't any gaps? This might be a question in semantics. The answer could be yes or no. Yes if your measurement is a detector or eyes that are no longer able to dtect the individual photon impacts. But no if you realize that this is a limitation of the detector, and that it's still a collection of individual photons just like when they could be seen striking the screen one at a time. But most importantly I don't know of any reason they would become connected just because there are lots of them...I would use the word "overlap" rather than connected. I hope my explanation makes sense but it's a little hard to explain. Just think about that video, and realize that just because you can't see the individual impacts at higher intensities, doesn't mean they aren't there. We have every reason to expect that they are.

Your post sounded pretty intelligent until you provided Walter Russell as a source. Look, the guy is so bloody stupid that he doesn't even realize the simplest things like how the sun causes the orbital mechanics of planets accelerating around them, as I point out here: www.abovetopsecret.com...
Even my 7 year old nephew understands simple orbital mechanics better than Walter Russell. The only reason I can see to read his work is if you already know physics, it's a good laugh on how someone can be so ignorant of physics yet pretend to be teaching others about it. If you don't know physics yet, and if you're quoting him as a source I can only assume you don't, then I'd avoid him as a source until you do learn physics, because you might get the wrong answer on a test question, when you're asked for example "what causes planets to accelerate in their orbit?", the correct answer is gravitational attraction from the sun, and you wouldn't want to answer "nobody knows" from your Walter Russell reading.

Originally posted by primalfractal
Does each shift in angle create another wave packet covering the arc with connected wave packets forming a paintbrush curve? This would seem to produce more photons than when left straight.

I think I missed addressing this specifically.

The rate of photon production in a laser depends on many factors. Input voltage and current could affect the rate of photon production, but if these and similar factors are fairly constant, the rate of photon creation should be also. Moving the laser wouldn't create more photons, it would just spread out the same number of photons over a wider area.

I can only think of one thing that would appear to change the photon production rate given these conditions, which is relativity. Move the laser source at 50% the speed of light relative to the ground, and a clock attached to it would appear to run 15% slower to a ground based observer, therefore, it would appear to produce 15% fewer photons per second as observed from the ground. However if you traveled along with the laser, the clock would run normally and there would be no change in photon production. The Earth and objects outside your reference frame would appear distorted, however.

reply to post by Arbitrageur


I am assuming that by "change of angle" you refer to the trajectory and not the phase. ?

in your hypothetical experiment, I think that moving the laser mid-packet would probably have the same outcome as any other type of quantum mechanical measurement: the function collapses to either of its basis states.

I am raking my brain trying to think how it could be otherwise.....


a fractional spin, maybe? it occurs to me now that the type of behavior the op is looking for is the fractional quantum hall effect in anyons. but a photon is not an anyon.

Originally posted by tgidkp
in your hypothetical experiment, I think that moving the laser mid-packet would probably have the same outcome as any other type of quantum mechanical measurement: the function collapses to either of its basis states.

Please clarify what you mean by either? "Either"seems to imply two possible outcomes, whereas the experiment I'm describing would have many possible outcomes of different trajectories, and yes I meant trajectories.

i think i found the answer to the proposed experiment suggested by arbitrageur. by using a smaller probe (shorter time interval) for measurement, you will introduce virtual particle interactions.

i think this could be legitimately described as "curving" the vector potential. but the REAL particles will only be manifest at their known energy quanta.

Running Coupling Constant

reply to post by Arbitrageur


by "either of its basis states", i am referring to the collapse of the wavefunction to ket1 or ket0. in the case of a laser, ket0 is filtered out which leads to the coherent phase. so, at the NEW trajectory, it will collapse either of its basis. no matter how quickly you move the laser, you will never change the angle (change the frequency) of the photon.

but, as i mentioned above, "either" can turn into a menagerie of intermediate states depending on the length of the probe.

reply to post by tgidkp

I think that might be related...thanks for the link. However it really doesn't describe the same experiment nor the outcome, but it does provide some insight into the approaches that could be used to predict the result of such an experiment.

Just did a word search on all three pages. No one mentioned that light does bend, it was predicted to bend by Einstein, and then it was observed directly over and over again. Its called Gravitational Lensing.

As to the exact mechanisms that light waves/photons bend by? Now you guys are starting to get into whats unknown. Its not known how gravity "propigates" exactally. So we dont know how gravity bends light. Relativity says its just the geometric bending of space/time, while quantum mechanics implies its "quantized" somehow. Thats were all the other stuff like string theory, loop quantum gravity, etc come from. Trying to fix this unagreement. Pretty cool you guys are getting to deep(er) concepts without meaning to.

Edit: I guess you guys were talking about lensing just never actually used the coined term so it didnt show up in my search. Still, whats with all the abstract ideas. fractional quantum hall effect? lol. Showing off a little???

Originally posted by primalfractal
Hi there,

Just wondering if science (or alternate science) recognises that light, in wave form, curves when emanating from a moving position.

An example of this would be to shine a laser pointer from the moon to Earth. The light travels around 356000km in 1.282 seconds. The moon orbits at 1023m/s so it travels 1.31km in the time the laser beam takes to reach Earth. The beam also spreads to around 100m diameter.

So if we were talking about particles this would produce an effect similar to shooting a machine gun from a car ie. the trail of bullets would appear to curve but each bullet actually goes straight. The curve is only apparent if you draw a line between each bullet.

But I’m not talking about particles, I’m talking about waves. A light wave goes from alpha to omega. From its source- the moon in this example, to its destination, Earth. As long as the source of the light is left on and nothing cuts it, a light wave is oscillating from start to finish.

Returning to the moon laser, the curve is evident from the moon being about 1km from where it was turned on when the beam reaches Earth. A light wave travels from alpha to omega so the light wave curves.

FUN. I just re-read the OP. Your thinking of light wrong! Each particle is emitied from a differnt reference frame according to SR, so thats why light doesnt really come one photon at a time! its a wave as well! this gets into the core of wave particle duality, and the real mystery of fundamental physics!

Edit: sounds like you got a case of the armchair experts. It happens when laymen read a ton of physics books made for laymen. They get all these great ideas, but they are missing the foundation so they easly miss the simple answers.

yup. certified armchair expert. oh, yeah, and show off too. on page three of a dying thread. look at me go.

so, why did you decide to whip your dick out? you have a physics degree I assume?

let us summarize the REAL expert's input: "no one understands light propagation" and "these guys are idiots". yes. very helpful.

Originally posted by ubeenhad
Just did a word search on all three pages. No one mentioned that light does bend

It was first mentioned by Astyanax here:

www.abovetopsecret.com...

Originally posted by Astyanax
You can't do Newtonian relative-velocity calculations with light. It always travels with the same velocity, and always in straight lines unless its path is distorted by gravity or a transition between media.

I mentioned it also, at least twice:

www.abovetopsecret.com...

Originally posted by Arbitrageur
Because as stated before, gravity has been shown to change the path of a photon

www.abovetopsecret.com...

Originally posted by Arbitrageur

Originally posted by primalfractal
I was trying to picture changing the angle of the wave packet while the wave is travelling along it. Would this occur in the OP from gravity, EM, and the Airy effect. So yes the light wave I was describing would still, I think, curve.

Yes to gravity, not experimentally confirmed to EM, and no to airy effect, see this article regarding the latter:

reply to post by Arbitrageur


Awesome! Thanks Arbitrageur for taking the time to answer me. As you can tell I am no pro Physicist so thank you for listening and expanding my understanding. These are just ideas I had that no one has been able to answer until you, Astanyx and tgidkp. As to Walter Russeli I thought the Mark McCutcheon comment interesting and just threw it in for dicussion. Not pushing his theory(didn't find it worth reading), liked some of his pictures though.

I guess even if it is semantics or "overlap" it can be seen as one curving wave, but composed of wave packets as you said.

Really happy you and tgidkp have understood and elaborated on my (admittedly modified) idea.

Maybe this has been tested but if so I'm not familiar with the experiment, and if not, maybe you could be the first to do the experiment? It would be interesting.

Hopefully someone could do the experiment, I'm not in the position to. Anyone please feel free, I believe it could be worthwhile. I would be very happy if someone did

Originally posted by tgidkp
i think i found the answer to the proposed experiment suggested by arbitrageur. by using a smaller probe (shorter time interval) for measurement, you will introduce virtual particle interactions.

i think this could be legitimately described as "curving" the vector potential. but the REAL particles will only be manifest at their known energy quanta.

Running Coupling Constant

reply to post by Arbitrageur

 

by "either of its basis states", i am referring to the collapse of the wavefunction to ket1 or ket0. in the case of a laser, ket0 is filtered out which leads to the coherent phase. so, at the NEW trajectory, it will collapse either of its basis. no matter how quickly you move the laser, you will never change the angle (change the frequency) of the photon.

but, as i mentioned above, "either" can turn into a menagerie of intermediate states depending on the length of the probe.

edit on 27-9-2012 by tgidkp because: (no reason given)

You have matched an exact theory to my idea, thank you. It was beyond me, I only had pictures. If it proves true prehaps we three have defined something new.

reply to post by tgidkp


My bad, not trying to step on toes. Its just seemed like all of you over complicated the mans question.

The armchair comment was rude. But true. Some of the words the OP knew, he shouldn't before learning more fundelmental concepts, like a full understanding of the duality of light. Then he wouldnt be confused.