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Quantum photon in more places ?

  1. Mar 14, 2005 #1
    :devil: Can anyone tell me if there are any practical experiments that show the undisputed proof to show that a photon (of any wavelength) interacts with one and only one electron ? As described in the photo-electric effect ?
     
  2. jcsd
  3. Mar 14, 2005 #2
    To my knowledge it is not possible to actually observe one photon. If it were, all the energy released would be absorbed by the device used to measure the occourance. You're better off researching tests/experiments that observed photons in the one million range. Give or take... I could be wrong.
     
  4. Mar 15, 2005 #3
    Interaction of photon(s) in question.

    I do believe there are experiments on single photons and on single electrons. Even though the measurement would destroy the energy released as you call it. The Heisenberg uncertainty principle takes care of the fact that some things can not be measured together, however this does not answer my question regarding the ability to see if millions of photons or millions of electrons (if you like) are indeed acting 1 on 1.
    What I really want to know is if 1 (or more) photons can act on more than 1 (or more)electrons as decribed in the photo electric effect ?
     
  5. Mar 15, 2005 #4
    Can a (any energy) photon be observed, such as in a cloud chamber,a photodetector, a photomultiplier a film or a bubble chamber or by whatever method and still affect further quantum "relatives" ? Can the same photon travel through after this observation or is the very measurement a guaranteed death of this photon ?

    Does a photon that interacts, with say a photomultiplier, smash an electron out of its orbit and (in case it has enough energy) carry on and smash more electrons out of their orbits ? A bit like a fast car crashing into more than one other victims at the time of crash.
    In the famous double slit experiment 1 photon can interfere with itself. The fact that we can observe a wavepattern, does that not mean the photon is actually interacting in more than one place ? Supporting the idea I just state above ?
     
  6. Mar 15, 2005 #5

    SpaceTiger

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    The number of electrons that a photon is likely to interact with when impacting an atom, semiconductor, conductor, etc. depends on the photon's energy and how tightly bound the electrons are. You can shine a single x-ray photon on a material and excite/release many electrons. In fact, that's very often done in x-ray detectors. This doesn't just apply to electrons in broad energy bands, either. A single photon can excite/ionize more than one electron from an atom under some circumstances. The exact sequence of events in these processes is, I believe, rendered intrinsically fuzzy by the nature of quantum mechanics (i.e. you can't always say that a photon acted in a specific way on a single electron). You have to think of it in some other way, like a solution to the wave equation or a combination of states.
     
  7. Mar 15, 2005 #6
    If a photon can indeed release more than 1 electron then it would be possible to use a semiconductor or other sensor to measure the number of photons as well as their wavelength in 1 measurement. Is that not a violation of the uncertainty principle ?
     
  8. Mar 15, 2005 #7
    What is the problem with the double slit experiment and a high energy particle. Surely you would expect we could trigger the "particle" sensor and have plenty of energy left over to do the "wave" part of the experiment. Yet the experiment collapses ! you either get a photon count or trigger or without the sensor in place you get a wave interference. See my previous posting on the (in)ability to do 2 measurements ?
     
  9. Mar 15, 2005 #8

    DrChinese

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    Not sure if I exactly understand your question, but...

    There is absolutely great proof that a single photon can be detected only once. Using an EPR/Bell setup, detection of a photon on one side coincides with only one detection on the other.

    http://marcus.whitman.edu/~beckmk/QM/grangier/Thorn_ajp.pdf
     
  10. Mar 15, 2005 #9

    SpaceTiger

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    There's some uncertainty in the measurements, but again, x-ray detectors do this all the time.
     
  11. Mar 15, 2005 #10

    reilly

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    By the way, it's well known in neuroscience that your eye can detect a single photon. See, for example, the elegant, readable, and superb book, The Retina, by John Dowling.
    Regards,
    Reilly Atkinson
     
  12. Mar 15, 2005 #11

    DrChinese

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    DrChinese's Theorem: It is always possible to think up ONE MORE TEST of the HUP which has not yet been documented in the literature. Key corollary: and that ONE MORE TEST will be the one to disprove the HUP.

    LOL.

    P.S. I have been guilty of this in the past myself. So I am laughing at myself.
     
  13. Mar 15, 2005 #12
    Gut feeling

    :smile: I like the quote and it gives me confidence that "better" experiments exist or can be developed to proove it wrong.
     
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