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Whats wrong with this picture?

  1. Jun 3, 2005 #1
    Someone please tell me why if the photon has no charge or mass, it is modeled as having an E and B field component?...

    An Electric or Magnetic field is created by a moving charge, obviously if the photon has no charge this makes no sense. Look up the definitions of electric field and magnetic field, magnetism ect. Tell me where you see it fit to associate such directly with the photon cause I just dont see it if the photon has no charge or mass.

    Electrons on the other hand are clearly the correct particle to attribute ElectroMagnetism to.

    The photon as it is can only be indirectly associated with EM, such that perhaps its intricate spin and other such properties or internal structure are information varibles that when the photon is incident on an Electron that information is translated into a physical change in the Electron; so in the context of many photons incident on many Electrons is a change in the Electric or Magnetic field... I mean its Electrons themselves that are ElectroMagnetism, you just cant have it both ways, as Ive said before, Electrons are the only particle with a charge or mass that can directly affect other particles with a charge or mass.

    Ok so explain to me why the photon has no mass or charge. Interaction of any kind whatsoever logically requires at minimum a charge or mass... In other words explain to me otherwise how something with no mass or charge excerts physical change in another object. Knowing that the above example I gave requires such also.

    Explain to me why the photon having energy GR says it can be affected by gravity... What the hell is "energy"? That word means nothing to me.

    Does anyone else believe in the statement "either something (a particle) has mass and exsists or it does not have mass and does not exist"? I associate "energy" with the later. No, energy can only be a property or measurement of quantity, a property of an object which has mass; so its not that gravity can effect it based on it having energy but based on the fact it has mass and exsists.

    How can something (a photon or gluon) exsist in absense of a physical componet (mass with geometry)?

    Do you really want me to accept the definition of the Electron as a "point like object" which has no concieveable geometry? I hope not...I really do. Instead tell me that our instruments cannot possibly resolve such, thats all you need to say, and that makes perfect sense to me. But dont ever try and tell me it has no geometry.

    Spin is one of those interesting topics in QM too because people try to avoid the idea of some particles having physical geometry which would logically be required for it to have intricate angular momentum (a rotating sphere).

    Enough for now, I dont even want to get into what are waves.

    Does anyone here believe in magic?
     
  2. jcsd
  3. Jun 3, 2005 #2
    I think you have a lot of concepts confused. I think the best place to start would be with the following question.

    Can you explain to me the difference between mass and energy? And tell me of an experiment where you can distinguish that difference.
     
  4. Jun 3, 2005 #3
    To be simple: you know the mass and the charge of an electron (m,e). These constants are not changed by the interaction (classical view). Hence the photon that exchange the (energy, momentum) between the particle and the electromagnetic field may not carry charge nor mass.


    To be simple. The photon has a momentum. Therefore it gravity may change this momentum (mainly the direction in simple schemes).


    Seratend.

    Once, you leave the mathematical explaination of a phenomenom, you can create your own description and call it magic if you want. : )

    Seratend.
     
  5. Jun 3, 2005 #4

    chroot

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    Yes, yes, that's right -- go ahead and attack physics before learning any of it.

    An oscillating charge produces an oscillating disturbance in both the electric and magnetic fields (the E and M fields are really two sides of the same coin, and you cannot disturb one without disturbing the other).

    Such oscillating disturbances in the E and M fields can be called simply "electromagnetic waves," and often are. Particularly when the wavelengths are very long as compared to your measurement instruments, or when they are emitted in a continuous, coherent beam by a laser, they seem wholly wave-like. A radio wave can be meters in wavelength, and, if you could see it, the carrier of a radio station would appear almost like a standing wave that permeates space -- not very much like a particle at all.

    On the other hand, consider a very brief "burst" of an electromagnetic disturbance -- one that looks more like the sinc function (http://mathworld.wolfram.com/SincFunction.html). Such a burst has a very strong central peak, and its amplitude falls off sharply only a very short distance from the peak. It's certainly still an electromagnetic wave, but now almost all of its energy is in a small volume of space. In fact, it behaves exactly as a "particle" would -- it can penetrate some kinds of barriers without changing its shape much, it doesn't diffract much even when passing small obstacles, and so on.

    That's it. That's the difference between a "wave" and a "particle" in the quantum-mechanical sense. Something "wave-like," such as a radio station carrier, has a well-defined wavelength but a poorly defined location. A standing wave exists everywhere inside a cavity. A very strongly peaked wave, however, has a well-defined location, but a poorly-defined wavelength. When such a strongly peaked wave interacts with matter, it behaves exactly as you'd expect a particle to behave. A burst of high-frequency oscillations, like an x-ray produced by nuclear decay, behaves very much more like a particle than the radio station's carrier does, but it's all the same stuff.

    - Warren
     
  6. Jun 4, 2005 #5
    masuder

    "I think you have a lot of concepts confused. I think the best place to start would be with the following question.

    Can you explain to me the difference between mass and energy? And tell me of an experiment where you can distinguish that difference."

    Dont bother trying to educate me, whatever you think you know about it, I know.

    To everyone, when I use the word mass, I use it instead of saying "a physical object" because everything that is physical has mass, the same thing.

    Look, my point is the photon having energy is not something that allows it to be affected by gravity. Potential, Kinetic, thermal ect. Energy is a property or quantity of something physical (mass). Gravity only acts on physical things. How can we say otherwise?

    Seratend ... mmmm, no, thanks for stoping by.

    chroot

    "An oscillating charge produces an oscillating disturbance in both the electric and magnetic fields (the E and M fields are really two sides of the same coin, and you cannot disturb one without disturbing the other).

    Such oscillating disturbances in the E and M fields can be called simply "electromagnetic waves," and often are. Particularly when the wavelengths are very long as compared to your measurement instruments, or when they are emitted in a continuous, coherent beam by a laser, they seem wholly wave-like. A radio wave can be meters in wavelength, and, if you could see it, the carrier of a radio station would appear almost like a standing wave that permeates space -- not very much like a particle at all."

    And the photon fits in all of this exactly how? And are you stating a difference between E and B fields (yes its actually "B") and electromagnetic waves, because you say that EM waves >>> disturb E and B fields. No that cant be what your saying. EM waves and the E and B field are one in the same thing, and yes you could say it like "oscillating disturbances" I GUESS.

    I like the rest of your reply but it doesnt really address my questions. Your explaination of why a wave may look like a particle is excellent. However I take it you dont want to assume a "classical" particle exsists, you only wish to recognize a wave exsists. So physically, what is a wave? Lets reverse your thought and explain why a particle looks like a wave instead. Tell you what, forget it Ive already done that. Re-read my actual questions and specifically try to answer them. Starting with this one...

    "Someone please tell me why if the photon has no charge or mass, it is modeled as having an E and B field component?... "
     
  7. Jun 4, 2005 #6

    chroot

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    Classical mechanics is just an approximation to quantum mechanics, and, in quantum mechanics, there are no such things as "particles" with hard boundaries and so on.
    Because a photon is a peaked oscillation in the electromagnetic field.

    - Warren
     
  8. Jun 4, 2005 #7
    Ah but see, the photon in an instance can be a peak in a wave, but what exactly is electromagnetic about it? Nothing if the photon as a whole has no charge. The electric field is described as and being created by a moving charge. Is the photon a moving charge?
     
  9. Jun 4, 2005 #8
    Is it true that refraction of light is an process of interaction between light and electrons ?
     
  10. Jun 5, 2005 #9
    Is this a trick question? I will answer Yes obviously because I certainly will not answer No, and that would go for my case that the photon would need a charge or mass for such to occur. It's not just that simple however, refraction involves a change in density of material through which light travels, a denser material has more electrons, is this coincidence? Probably not, we can say that light interacts (possibly absorbed and re-emited) with more electrons slowing it down... Quite interestingly a change in overall velocity induces a change in direction according to refractive index of a material. I dont think its %100 clear why when velocity of a light wave slows (increase in wavelength) equates to a change in direction. I would put it more along the lines of spin states (angular momentum and magnetic moments) of particular atoms (light element vrs heavy element) that equates to a change in direction/momentum of light. If we have an object or substance that varies in atomic elements we should see light exhibit a very non straight path through it which we do. It all boils down to amount of electrons and alingment or spin state of those electrons. Different materials Normal mode wave resonance give a prefered direction of light emission, and again this is according to spin states which further relates to magnetic moments. This is more than I need to say.

    The photon can also supposedly interact or rather be absorbed directly by the nucleus of an atom in a process called pair production which may surprise some (if that senerio is indeed correct) as most might think that photons only interact with electrons. Again pair production interaction would be no exception to my case, the photon needs a mass to do such.
     
  11. Jun 5, 2005 #10
    Thanks tdunc,

    I asked it because it is an event when light interacts with matter and understanding that should reduce many of our doubts about it.
     
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