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Does wave/particle duality apply to the full EM spectrum?

  1. Jan 7, 2015 #1
    My question relates to wave/particle duality.

    If light is regarded as possessing both wave like and particle like properties, and visible light is just part of the whole EM spectrum of radiation, is it correct to say that radio waves for instance, ( being themselves part of the whole spectrum of EM radiation), also possesses similar wave like and particle like qualities?
     
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  3. Jan 7, 2015 #2

    Drakkith

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    Yes. All EM radiation is quantized into photons, regardless of the wavelength of the wave.
     
  4. Jan 7, 2015 #3
    Don't ALL atoms possess wave particle duality? I don't mean that as in a feature of an atom, but all atoms experience this phenomena, correct?
     
  5. Jan 7, 2015 #4

    Drakkith

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    Yes. All particles, including composite particles such as atoms, have wave-like and particle-like properties.
     
  6. Jan 8, 2015 #5
    In general, the shorter the wave length the more the particle-like properties will be observable.

    The longer the wave length, the more the wave-like properties will be observable.

    But if you look closely enough with the right experiment you can find both properties for all EM radiation or even massive particles like electrons or atoms.
     
  7. Jan 8, 2015 #6

    Nugatory

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    One caution here: "Wave-particle duality" as a scientific concept was discarded seventy-five years ago, when Dirac and others came up with the basics of modern quantum mechanics.

    It is true that all quantum things will display wave-like behavior in some measurements and particle-like behavior in others, but that doesn't mean that they are both waves and particles. They are neither. A sheep has four legs like a table and a sheep is fuzzy like a pillow, but you wouldn't try to understand the behavior of sheep in terms of "table-pillow duality" - so don't think in terms of "wave-particle duality" when it comes to quantum objects.
     
  8. Jan 8, 2015 #7
    So as I now understand it then; radio waves can be described as also consisting of particles - and that the latter can legitimately continue to be described as photons (albeit possessing far lower energy levels than that of say, visible light)?
     
  9. Jan 8, 2015 #8

    Drakkith

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    If by "consisting of particles" you mean "has its energy quantized" then yes. The energy per photon of a radio wave is far lower than visible light. A 100 MHz radio wave photon has roughly 4.14x10-7 eV of energy, whereas visible light photons are roughly around 1.5-3.0 eV's.
     
  10. Jan 9, 2015 #9
    Is it not correct that Quantum Field Theory only treats particles as waves? I recall a video by Sean Carroll where he essentially said that the particle aspect of matter is not part of the QFT/Standard Model description of nature and so is misleading...


    IH
     
  11. Jan 9, 2015 #10

    Nugatory

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    Not correct, although...
    ... is reasonable enough. QFT doesn't treat particles the way that a non-specialist would interpret the word "particle", but it doesn't treat them as waves either. It's hard to get the ideas across without using some fairly challenging math, but Richard Feynman has succeeded; try his book "QED: the strange theory of light and matter" for a good non-technical explanation of how QFT works.
     
  12. Jan 9, 2015 #11

    sophiecentaur

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    OK as long as you realise these 'particles' are nothing like little bullets. That naive model is just not a good one and will not help you. It is the quantisation of the energy and momentum that is most relevant (E=hf and P = h/λ).
     
  13. Jan 9, 2015 #12
    I refute the 'naivety' tag Sophiecentaur. :)
    Perhaps clumsiness would be more appropriate, but was referring to the original question re. wave- particle duality and assumed this would be realised and that I need not refer to the 'particles' as 'quantized energy'.
    I have to admit however that as a layman, prior to this discussion I had never before heard that the 'quantized energy' of radio waves is described in terms of also being a photon. So thank you to the contributors for the clarification. ( Though still trying to digest and conceptualise what has been said). I can understand the mechanics of the process of the creation of a photon in relation to visible light, but finding it difficult to apply the process in relation to the creation of radio waves.
    The discussion has also made me ponder on the following;
    An electron [on a reflective surface] emits a photon with the quanta of a radio wave. If at the same time, photons are being created in the visible spectrum from the reflective surface from an external source - is it therefore correct to assume that the electron is therefore emitting photons at both the radio and visible light spectrum of EM radiation at the same time?
     
  14. Jan 9, 2015 #13

    sophiecentaur

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    I was not using the word 'naive' in a critical sense and it was certainly not meant personally. Sorry if it appeared that way. The Corpuscular theory of light is naive and was thrown out centuries ago. It is naive to think in terms of corpuscles because nothing about light can be described that way. Until one is fairly competent with quantum matters, it is not really necessary to deal in photons. In fact, the extremely low energy associated with quanta of RF radiation turns it into a very Classical - like phenomenon. Even the way that electrons interact with RF waves is not on a 'one electron - one photon' basis. The interaction is not like the familiar Hydrogen atom model would suggest. In condensed matter, the EM waves interact with the whole of the medium - which is why you can get refraction and not scattering.
     
  15. Jan 10, 2015 #14
    Thanx for the reference, I will get the book and try (fingers crossed...) to get a basic understanding of QFT...

    IH
     
  16. Jan 11, 2015 #15
    Thank you for the book referral.Have started reading same so will reply when I have read it through.
     
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