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Science

Electron Fission 22

Posted by Hemos from the split-it-and-spit-it dept.
Scott_Marks writes: "A Science News story this week reports on some research by Humphrey J. Maris of Brown University predicting that in liquid helium electrons could be split in two. This seems not to be just your sorry-Dr.-Einstein probablistic one-thing-in-two-places effect, but an actual separation. (Does that distinction even make sense in the quantum world? Over my head.) Maris will give a talk on this later this month near me at N. C. State, so I'll be there. Makes me wonder what it would be like for a physics colloquium to get Slashdotted."
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Electron fisson More

Electron fisson

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  • I sure would like to read the story, not just the references.
  • It doesn't seem the article itself is online. The references are all that are linked from the Science News homepage [sciencenews.org]. A subscription is probably required to get the actual story.

    -Erf C.
  • Yeah, a subscription to the magazine. I don't mind having to register to read a NY Times article, but why post something about a story we can't read?

    That kind of makes it difficult to have an intelligent discussion on the matter.
  • I tried to find more info about his work online, but there doesn't seem to be much. The best I came up with was a short press release [brown.edu] about his work and its appearance in a journal article.

    Mindpixel [mindpixel.com] - help the Digital Mind Modeling Project.

  • Hmmm... Quite interesting. The main meat of the process:
    According to quantum theory, the state of a particle is described as its wave function. The probability that the particle will be found in any position is proportional to the square of the wave function at that point in space. Maris' theory considers what happens to electrons when they are immersed in liquid helium at a temperature of one degree above absolute zero. Previous experiments have shown that an electron in helium becomes trapped in a bubble approximately 100-billionths of an inch in diameter. The bubble drifts through the liquid with the wave function of the electron confined inside it.

    Maris shows that when the bubble is illuminated with infrared light, the bubble can divide into two smaller bubbles each containing a part of the wave function of the electron. These two bubbles can then move independently through the liquid and become separated from each other.

    I think that the important thing to realize here is that they are talking about the wave function of the electron being inside the bubble and splitting in two, not the actual electron. IANATP (Theoretical Physicist), but if I recall correctly (especially since the quote above agrees...), the wave function of a particle is actually a measure of the probability that that particle will be found in a particular place when you look for it. This press release seems to be nothing more that Schrodin ger 's Cat [anu.edu.au], but with an electron instead of a cat (the SPCA [spca.org] is happy about that). I suspect that if you check in the bubbles for electrons, one would have an electron, and the other would not. It is the act of observing that causes the wave function to collapse into an actual physical property. So, I don't think that we're actually talking about electron fission here, but electron wave function fission.
  • Forget whether or not the story is actually posted online, let's explore the possibility itself here.
    It sure would be a kick in the ass for the Physics community if this could actually work. Einstein said that giving the actual location of an electron at any given point in time would be next to impossible, and what has always erked me about this, is how it makes matter transportation impossible.
    I mean, forget the bombs here, let's work on Teleportation. It has been argued that the theory itself relies on being able to take a "picture" of all the matter of an object and re-creating that energy in the form of matter where one would be teleported to...
    If they can now deal with the problem of electron-location, then this could actually WORK!
  • The article, in my opinion, is horribly vague, to the point where it is very difficult to discern what it actually means. Is it, as someone else suggested, regarding the fission of electron wave functions? Or is an electron being physically split here? The differences between the two are astronomical. Splitting a wave function merely relates to separating into two parts a function which will relate to an observer the probability of the electron being found in a certain place at a certain time. However, to actually split an electron would be truly something; as a member of the lepton family, electrons were understood to be the fundamental building blocks of matter. Its accompanying neutrino, along with the muon particle, the tau particle, and their accompanying neutrinos, made up the leptons. The leptons, in turn, with the six quarks, comprised the "chassis" of the Standard Model, that is the theory describing the nature of matter, in which the quarks were affected by the strong nuclear force, and the leptons were not. Were an electron to be actually physically split, it would open up a whole new realm of particle and subatomic physics. Wow. It would be like smashing the pieces of the smashed pieces of the smashed pieces of the atom. It would be greatly appreciated if someone could clarify the nature of the statement in question.
  • Allright, so you look at the bubbles and find that the electron does exist in one of them. What do you think would happen to the 'empty' bubble?

  • I guess I didn't really say that too well. I agree that the wave nature of the electron is very important in this experiment, however, I would find it hard to have a discontinuity in the wave function of the electron (as the doctor states) without it splitting into two physical entities. In a double slit experiment, you only see the electrons hit the screen one at a time - you don't record a wave hitting the screen. It is only after many have hit the screen, and you record where they all hit, that the pattern emerges. In effect I'm saying that you can't directly observe the wave function (it is just a consequence of the statistical nature of QM) and therefor it couldn't 'make' bubbles which can be observed.

    If you're very interested in these types of QM musings I highly suggest reading "Wholeness and The Implicate Order" by David Bohm. It is definately one of the most interesting books (and easy to follow) I've read in some time.

  • Electrinos! (Score:4)

    by Mad Hughagi ( 193374 ) on Wednesday October 04, 2000 @09:15AM (#732341) Homepage Journal
    This article aired on the AIP physics news update last month. You can check out their take on it here:

    http://www.aip.org/enews/physnews/2000/split/pnu50 1-1.htm

    It's quite an interesting concept, it will be cool to see what further experiments reveal.

  • Thanks for the book recommendation; I'll have to look into it. (As my "To-Read List" gets longer and longer...)

    In the two-slit experiment, you also have a discontinuity in the wave function of the electron: the slits. The experiment with the bubbles that is discussed is essentially the same as the two-slit experiment, with the slits replaced by the bubbles. The main difference, however, is that the bubbles constrain the wave functions such that they cannot interfere with each other.

    Imagine, if you will, that we run the two-slit experiment, sending through one electron at a time. We know that we will build up the wave-based interference pattern on the screen. Now, we manage to stop time at the precise instant when we know an electron (or its wave function) will be going through one slit or the other. We know at this very instant that there is a probability of the electron existing in the left slit, and an equal probability of the electron existing in the right slit, and no probability of it existing anywhere else. We thus have a discontinuity in the electron's wave function, except with the wave function constrained by slits instead of bubbles.

    I will agree that you can't directly observe the wave function; anytime you try to it will collapse into a particle. However, you can indirectly observe it, and this is what the two-slit experiment does. If you put a detector on each slit to see which slit the electron goes through, you end up with a different pattern on the screen that you get without the detectors. By looking for particles, you are forcing the wave function to collapse, and so you eliminate the wave interferece pattern. Also, if the electron is physically splitting in half, and half of each electron is going through each slit, we would not end up with an interference pattern to begin with, particle detectors or no.

    Thus we know that, without the detectors, it is the wave function that is traversing the experiment, and that at some point this function must be discontinuous to create the interference pattern. So in these bubbles there is nothing new in the behavior of the electrons and their wave functions that is not already present in the two-slit experiment.

  • It sure would be a kick in the ass for the Physics community if this could actually work. Einstein said that giving the actual location of an electron at any given point in time would be next to impossible, and what has always erked me about this, is how it makes matter transportation impossible.
    I mean, forget the bombs here, let's work on Teleportation. It has been argued that the theory itself relies on being able to take a "picture" of all the matter of an object and re-creating that energy in the form of matter where one would be teleported to...
    If they can now deal with the problem of electron-location, then this could actually WORK!
  • Firstly, I'm going to just let an opinion fly about reductionist principles in general - even if they do bust the electron into bits, would it even matter in the grand scheme? One of the things in physics is that most theories are only valid for certain scales and they are only approximations to the next level down (or up I suppose). Although this would lead us into a new level of research it would be the exact same thing over again. Important none the less but I don't think too many physicists would be peeing their pants in glee over it.

    As for the question about the difference between the wave function and the particle splitting up, I don't think this article means to determine what is actually seen. It only states that a very interesting behaviour of this experimental apparatus was noticed (multiple bubble formation when only one was expected) that might indicate the existance of electrinos (the proposed name for the remains of the electron) and that further experiments are going to be undertaken to consolidate what is actually observed.

    The researcher is very hopeful that he has in fact observed electrinos however the physics community as a whole is skeptic, so I guess we'll have to wait until a further date.

  • I would theorize that the "empty" bubble would disspate, since it would no longer have any part of the electron wave function in it. However, it might just become an empty bubble. (Hmmm... Here I am, saying, "I think that it will disappear; of course, it might just stay around." Is it still to late to run for political office? ;-))

    Okay, now that we've got theories for the results, who's going to volunteer to do the experiment?

  • forget the bombs?! hell no, get this working, get matter transportation working, then we have the ultimate strategic weapon delivery system.
    --
    Peace,
    Lord Omlette
    ICQ# 77863057
  • Ummm......no....I think.

    One of the fundamentals of quantum mechanics is that given any instant point in time you can know either the position of a particle of particle OR its energy. Measuring the one alters the other. What the wave function of a particle does is attempt to predict both.
    Splitting the wave function does not actually split the particle, this is merely a 3-dimensional model of the interference pattern described in other comments. In other words, instead of knowing that the particle is somewhere in space A, and not elsewhere; you know that the particle is either in space A, or space B, and not elsewhere.

    IADJNATP (I Am a Doctor, Jim, Not a Theoretical Physicist)
    Averye0
  • Ok, here's the flaw with that arguement, (one that is often made with quantum mechanics since it is often presented with an over-emphisis placed on the 'reality' of the wave function) the wave function would not have the ability to 'make' the bubble in the first place. If you found the electron in the bubble, you would also only find one bubble, the one with the electron in it! The other bubble would have never existed! The fact that there are multiple bubbles either implies that the electron actually split up, only to recombine later, or that there is some other effect creating the extra bubbles.

  • i am not so sure how reliable this press release is, considering that they refer to neutrons and protons as elementary particles, which they most certainly are not. plus, splitting a wave function just splits the probability that you will find the electron in a certain place. it would make it (for example) half as likely to be in one bubble as the other. although the electron may be fissionable, this is probably not the experiment that will prove it.
    best slash sites:infantililsm.org [infantilism.org]
  • When I was a child in the early '50s, educated people that I knew were seriously worried that all of this experimenting with the fundamental particles of matter would cause the entire universe to explode or disintegrate in a gigantic chain reaction. And I couldn't have an Altair computer kit because it would just be a waste of time and money, since computers would never be of any use. Hmmm. I wouldn't discount this kind of work too quickly.
  • Please elaborate on this "electrino" of which you speak. Have any properties or anything for it been proposed? I find the idea of splitting a lepton utterly groundbreaking. It would add a completely new aspect to the concepts of Supersymmetry and the Standard Model. Of course, then, accompanying research would have to be done to dissect all other leptons and quarks. Would these electrinos be affected by W and Z particles? The electromagnetic force? Only time will tell.
  • The electron is the wave function. They are one and the same thing. It means nothing to describe the electron as a point charge in space, if you split the wave function you split the electron also. This is the very basis of quantum mechanics, wave - particle duality.
  • But the wave function does have a reality. When you run the two-slit experiment [uoregon.edu], sending only one electron through the aparatus at a time, you still end up with an interference pattern. If the wave function had no reality, you would end up with a two-maxima distribution when you use one electron at a time. Unless you are actually looking for a particle, it is the particle that has no reality. Until you actually look for the electron, there is no physical electron to "actually split up".

    You postulate that there might be some other effect creating the extra bubbles. That I could probably buy into. However, saying, "...the electron actually split up, only to recombine later" presents significantly more problems than it solves. Doesn't that mean that we could open just one of the bubbles, and look at a bare half-electron? I think that that would have been trumpeted very loudly in the quote above if it had been observed.

    Or does the fact that we try to observe the half-electron make it instantaneously recombine with another half-electron? If it does, does it always grab its other original half? If it grabs its other original half, how do you distinguish that from the collapsing wave function that I talked about earlier? When it grabs its other half, does it leave the bubble that the other half had been in intact, or does the bubble dissolve without that half-electron still in it?

    If the half-electron doesn't always grab its original other half, doesn't that mean that we would sometimes be able to open both bubbles and find an electron in each? Where do these two "new" half-electrons come from? Have we just performed an energy to matter conversion, or did some other electron outside a bubble just split? If an electron outside a bubble can split, and there is no reality to the wave function, then how come there have been no observed half-electrons in nature yet? After all, this isn't a high-energy event.

    Applying Occam's Razor, I think that I'll stick with the collapsing wave function. Saying that we are dealing with two half-electrons conflicts vastly more with existing observations; dealing with the wave function falls right in line with them.

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