Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

List of Electron Double Slit Experiments?

  1. Jun 23, 2010 #1
    I've been reading some papers about electron double slit experiments, including the one by Jonsson which seems to be the most detailed and well written so far, but I've only been able to find about five papers total. Jonsson was one, then a 1989 single-electron double slit experiment, and a few others. Anyway, I'm noticing that a lot of these papers do not give sufficient detail to know whether they might have introduced systematic errors into their data. (The data is qualitatively consistent with QM so I assume that's considered good enough evidence that they didn't, but I'd still like to walk through all the possibilities for myself.) Also, the number of papers I've been able to find is pretty small. Can anyone recommend a comprehensive, or at least large, list of electron double slit experiments? I've been trying to use scholar.google.com but I get a lot of unrelated papers.

    A few of the things I'm interested in finding are...
    1) have experiments been done with the same apparatus but with the angle from the electron source to the slits changed to several different values,
    2) where the distance from source to slits was varied to several different values,
    3) where the number of electrons being emitted by the source was counted and all electrons (or a large %) were quantitatively accounted for, such as by placing detectors adjacent to the slits
    4) where the distance from the slits to the electron detectors was varied
    5) where the point of detection (and time) of each electron was recorded and is available in a table so statistical formulas can be applied to the distribution, rather than just looking at the distribution qualitatively

    For example, even in Jonsson's experiment, the schematic of the apparatus is only shown for 2 slits, and it looks like the source is pointed directly between the two slits. In the case of 3 slits, does it point directly through the 3rd slit? In the case of 4, is it in the middle dividing each pair? I assume so, but it'd be nice if he said so.

    Basically, I would just like to see that the experimental conditions have been varied sufficiently to make it very unlikely that some sort of unknown error is being introduced into the experiment due to some behavior not yet discovered because the conditions haven't been varied. I know there's probably no reason to suspect this, but I think it's best to check anyway just to be sure. I've been really surprised so far that in these papers nobody said "Well, what if we move the apparatus like this..." and reperformed the experiment a dozen times with a few things changed just to see what happens (probably nothing, but who knows unless we experiment?).
     
  2. jcsd
  3. Jun 24, 2010 #2

    alxm

    User Avatar
    Science Advisor

    Jönssons was the first proper double-slit experiment with electrons. But you realize the physical phenomenon of interest here is diffraction? And the first example of that was Thomson and Davisson, years earlier.
    Today there's a dozen or so different electron diffraction spectroscopy methods in regular use, and hundreds of crystal structures which have been studied by them. Every single one of these is in effect a variant of the double-slit experiment for electrons.

    In short, the 'wave-like' nature of electrons is beyond dispute and does not, and never has, hinged upon the result of the double-slit experiment alone.
     
  4. Jun 24, 2010 #3
    Apologies in advance for the redundant "I know"s below. I just want to make a point that I didn't ask for the following information, as I already have it, and that the answer I got did not answer my original question. I am noticing a habit on this forum (from several other threads) of deflecting questions, saying they don't need to be asked, or questioning the motives of the person answering the question, instead of answering them. I know everyone is just helping out of the spirit of helpfulness to the scientific community, but I would really appreciate a solid answer, or if there are no more experiments and you know that please just say so. If you don't want to answer, or if you think the question is stupid, don't answer, but please don't answer by deflection, it's not helpful to me and just wastes my time and yours.

    Yeah, I know.

    Yes, that's the phenomenon being investigated by the experiments. But what I'm interested in investigating is the experiments themselves.

    Yeah, I know, 1920s, found by accident.

    Yeah, I know.

    Sure, but I'd still like to see some experiments like the ones I'm looking for above, or at least more experiments. Do you know of some papers I can look at that involve N-slit experiments with electrons and are primarily concerned with that (not as a footnote in an experiment with some other purpose, for example)?

    I wasn't disputing it.
     
  5. Jun 24, 2010 #4

    alxm

    User Avatar
    Science Advisor

    I wasn't 'deflecting', I just don't see what the point would be in many repetitions of the exact same experiment, when the phenomenon the experiment was designed to show is already very, very well-verified. Most experiments never get repeated. Five repeats (under the same or similar conditions) would be a high number, not a low one.

    So yes, I questionedyour motives - but only because I really can't see why anyone would have spent their time and money repeating it more than once or twice (seeing as it's a nice and important experiment).
     
  6. Jun 24, 2010 #5
    Here's a recent experiment from earlier this year which has quite a few details (Although I'm not sure if the results are correctly interpreted, since he claims to show that the electrons don't interfere with themselves but only with an "EM component" that passes through the slits, so that which-way information for the electrons can be obtained without destroying the interference)


    Experiments performed in order to reveal fundamental differences between the diffraction and interference of waves and electrons
     
  7. Jun 25, 2010 #6
    Yeah, what crazy person would ever want to repeat an experiment? Maybe to make some changes and learn something new that wasn't revealed by previous experiments. Nahh, that'd be too scientific.

    Clearly early experiments showed that feathers fall slower than lead, so why would we want to do something crazy like try the same experiment in a vacuum? You doubt that the original experiments accounted for all outside influences? I question your motives! You're obviously trying to bring down the state.
     
  8. Jun 25, 2010 #7
    Why don't you quit trolling and do the experiment yourself, according to whichever variation you're interested in?

    The thing is, everybody in mainstream physics feels convinced in this case by the experiments that have already been done, nobody has any reason to expect any different results. So what's in it for the experimentalists? They'd rather earn prestige by testing something new, answering a question that has puzzled many theorists, trying to beat the limits that competing experimentalists have set, hoping to prove something contrary to what others expect, scratching a personal itch.. They aren't going to squander their resources tediously trying to satisfy every internet-troll's standards of science for no further reason. The journals won't even publish reports that are too uninteresting.

    Now, you gave 5 parameters you'd like to see tested. Why did you pick those ones? I presume you are considering some alternate model in your mind, and that therefore you suspect there is a chance that by varying some of those 5 parameters your model will anticipate a result differing from the mainstream prediction. Perhaps if you forthrightly summarised that alternate model for us, we might be able to be more helpful (perhaps bring to your attention completely different experiments that would have already been relevant regarding the alternative model you are weighing).
     
  9. Jun 25, 2010 #8
    Cesiumfrog, I don't mean to be trolling. Actually "unusualname" posted a link to an experiment where several parameters were varied and it shows some problems with the current view of the electron, so my suspicions look to have been correct. However, I'll wait to see what comes of this paper he linked to to make any firm conclusion. It looks as good as any of the other 5 papers though. Anyway, bottom line is, maybe everybody should be a little bit less secure in their confidence in current models? A healthy amount of suspicion is good for science.
     
  10. Jun 26, 2010 #9
    Hi,

    I'd really like this thread to keep going - there's the potential for some very specific, well-thought-out debate - so I've got something to add.

    I also doubt the QM explanation for the double-slit/diffraction experiments. Well, that's not quite true - I don't agree with the pop science explanation that the electron 'interferes with itself'. Maybe there is a more rigorous explanation that someone can write concisely and without jargon? :-)

    Anyway, let's consider an alternative model for these experiments (for electrons first, light can come later):
    1. The electron interacts with the atoms around the edge of the slit, as it passes through. It gets bent off-course.

    Has anyone proposed this theory before? What are the challenges to it?


    Please respond. I want to learn something. And we need to get down to the nitty-gritty of this experiment to test just how solid the current explanation is.

    Cheers,
     
  11. Jun 26, 2010 #10
    Very_curious, that's similar to the experiment linked to by unusualname above. It appears to show that the current view of the electron is incorrect.
     
  12. Jun 26, 2010 #11
    Why don't you quit being coy, and articulate your suspicions? Then we may have the opportunity to share them with you, or perhaps we may be able to point out something more useful to you.
     
  13. Jun 26, 2010 #12
    That is an extraordinary claim. Please explain in detail what you mean.
     
  14. Jun 26, 2010 #13
    It's all explained in the paper unusualname linked to above in this forum. I think it would be best if anyone interested read it for themselves rather than me giving my interpretation on something that's easily available to all. I'd like to hear what you think of it when you have the time.
     
  15. Jun 26, 2010 #14
    I'm not really being coy, I've already said what my suspicions are. My suspicion is that there might something more that can be learned from double-slit type experiments, some new property or behavior that we don't currently know. On the other hand, there might not be.

    However, it is not a suspicion, but a firm statement, that the previous experiments did not adequately vary the experimental conditions in such a way that might reveal unexpected properties, according to the standard I would apply to myself if I were making similar experiments.

    I said as much in my first post that started this thread.

    If it was me doing the experiments, which I may do eventually later in my career, I would have varied the conditions much more. The paper linked to in this forum did some things similar to what I was suggesting in my first post, and in doing so appears to have revealed the sort of unexpected properties I thought might be. I have some suspicions about this new paper as well, but assuming the paper accurately describes the experiment and results, it requires us to reconsider some things.
     
  16. Jun 27, 2010 #15
    I don't believe there is anything new to learn about the behaviour of electrons from double slit experiments, and any experiment which claims different behaviour to what can be explained by our current model of the electron and QM is probably misinterpreting the results or making wrong assumptions about the apparatus.
     
  17. Jun 27, 2010 #16
    Can you be more specific?

    What in your view, precisely, does the double-slit experiment confirm?

    Please do a bullet-point list of properties of the electron so we can go through them in turn and check that the double-slit experiment results don't clash with any.

    Cheers,
     
  18. Jun 27, 2010 #17

    jtbell

    User Avatar

    Staff: Mentor

    I see no details at all about his experimental apparatus and method.

    Upon Googling around for information about Demjanov, I found a reference to an article by him, published in Physics Letters A in February, which claimed to have detected the motion of the Earth through the aether by studying the speed of light in a dielectric medium (as far as I can tell). However, the link to the article leads to a retraction notice from the journal publishers:

    This paper was on a different subject, but it doesn't give me much confidence that the one we're discussing here is any more valid.
     
    Last edited: Jun 27, 2010
  19. Jun 27, 2010 #18

    Cthugha

    User Avatar
    Science Advisor

    Short answer?
    If I had bothered to read the references section at the beginning, I would not have wasted some valuable minutes of my life. This "paper" is somewhere between nonsense and crackpottery. That guy cites his own "publications" called "The aetherodynamic determinism of the Primodials" and "The aetherodynamic ins and outs of the relativity and quants".
    My best bet is that this stuff will never get published in a peer-reviewed journal - for good reasons. That guy claims that probability waves and the Heisenberg uncertainty principle are nonsense without any experimental evidence - and no, I do not consider his very strange interpretations of questionably performed experiments evidence.
     
  20. Jun 27, 2010 #19
    Double slit experiments confirm the wave nature of particles, this was hypothesised in 1923.

    There are mathematical models which derive the wave equations for various particles, the Schrodinger eqn is very accurate for massive non-relativistic particles, in other cases you can derive wave equations from the Dirac equation or QFT, in the case of photons it turns out to be the Maxwell EM wave known in the 19th century.

    I don't think there is much more to be said.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: List of Electron Double Slit Experiments?
Loading...