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Thread: Do virtual photons have wave properties?

  1. #1
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    Do virtual photons have wave properties?

    All matter has wave properties. Photons are particles of light,
    which have -- or consist of -- electric and magnetic waves which
    always travel at the characteristic speed of light.

    Virtual photons are the particles which carry the electric force
    between electrically charged particles. Do virtual photons also
    have or consist of electric and magnetic waves? Do they also
    travel at the speed of light?

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  2. #2
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    Virtual photons would have virtual wave-like properties. Since virtual photons are not observable, the answer cannot be tested.

    Information about American English usage here and here. Floating point issues? Please read this before posting.

    How do things fly? This explains it all.

    Actually they can't: "Heavier-than-air flying machines are impossible." - Lord Kelvin, president, Royal Society, 1895.



  3. #3
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    Quote Originally Posted by swampyankee View Post
    Virtual photons would have virtual wave-like properties.
    I assume that in saying "wave-like" rather than just plain "wave", you
    are expressing a preference to call all particle "wave properties"
    "wave-like" properties, not just those of virtual particles.

    What do you mean by "virtual wave-like properties"? Are the properties
    of virtual particles themselves virtual? Or are the waves virtual? What
    does either of those statements mean? How are virtual properties
    different from physical properties, or how are virtual wave-like things
    different from physical wave-like things?

    Quote Originally Posted by swampyankee View Post
    Since virtual photons are not observable, the answer cannot be tested.
    I agree that virtual photons are not observable. Why does that imply
    the question of whether virtual photons have wave-like properties
    cannot be tested?

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  4. #4
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    Quote Originally Posted by Jeff Root View Post
    Do virtual photons also
    have or consist of electric and magnetic waves?
    I'd say no. If you're looking at a virtual particle model of this, there really are no classical electric or magnetic fields to mediate the electromagnetic interaction, because that's precisely what the virtual photons are doing. Or, perhaps better, the virtual photons are quantized excitations of the field. But I think the semiclassical image of a photon as a wave packet of electric and magnetic fields travelling together doesn't really apply to even real photons if you're modeling things with virtual particle interactions. Perhaps it would be better to say that the electric and magnetic waves are made up of virtual particles and their interactions, rather than the other way around.

    Quote Originally Posted by Jeff Root View Post
    Do they also
    travel at the speed of light?
    Not necessarily. In fact, they're often not well localized at all, and so can't be considered to "travel" the way real objects do. For example, take a virtual photon that is carrying momentum oriented to the left (for some particular coordinate system). Even though one would think that such a photon should in fact be moving left, since that's the direction of its momentum, it's entirely possible for it to be emitted by one particle and then absorbed by a different particle on the right. Although, again, once we're looking at interactions as being mediated through virtual particles, I'm not sure it's entirely correct to even talk about real particles as having definite trajectories and velocities anymore.
    Conserve energy. Commute with the Hamiltonian.

  5. #5
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    I'm curious how the Casimir effect can be treated regarding wave & field effects for virtual particles. Would it be fair to picture a virtual particle/wave poping in and out from a field be one way of seeing it? The wavelengths, even if short-lived, seem to be causal to the effect, but I'm only guessing.
    We know time flies, we just can't see its wings.

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    One way to look at the Casimir effect is that the small distance between the surfaces impedes the creation of virtual photons with wavelengths greater than the distance. This is more of a visualization than the full QFT treatment.

  7. #7
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    Quote Originally Posted by Jeff Root View Post
    I assume that in saying "wave-like" rather than just plain "wave", you
    are expressing a preference to call all particle "wave properties"
    "wave-like" properties, not just those of virtual particles.

    What do you mean by "virtual wave-like properties"? Are the properties
    of virtual particles themselves virtual? Or are the waves virtual? What
    does either of those statements mean? How are virtual properties
    different from physical properties, or how are virtual wave-like things
    different from physical wave-like things?


    I agree that virtual photons are not observable. Why does that imply
    the question of whether virtual photons have wave-like properties
    cannot be tested?

    -- Jeff, in Minneapolis
    Virtual photons can't be observed; if they cannot be observed, how can their properties be tested, vs determined by modelling?

    Information about American English usage here and here. Floating point issues? Please read this before posting.

    How do things fly? This explains it all.

    Actually they can't: "Heavier-than-air flying machines are impossible." - Lord Kelvin, president, Royal Society, 1895.



  8. #8
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    Quote Originally Posted by Reality Check View Post
    One way to look at the Casimir effect is that the small distance between the surfaces impedes the creation of virtual photons with wavelengths greater than the distance. This is more of a visualization than the full QFT treatment.
    That looks like a great way to think of it. Thanks. [I hope you're right.]
    We know time flies, we just can't see its wings.

  9. #9
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    Look at it this way: electromagnetic field includes freely propagated electromagnetic waves.
    Free electromagnetic waves are quantized into real photons.
    But there are other electromagnetic fields. Such as electrostatic and magnetostatic fields, which are not freely propagating.
    So, how is electrostatic field quantized?

  10. #10
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    [QUOTE=chornedsnorkack;2397409
    So, how is electrostatic field quantized?[/QUOTE]

    Charge is quantized along with the particle, which can be electrons, quarks, muons, etc...

    I obviously don't understand your question because the answer is just too easy.

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