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More Quantum Strangeness: Particles Separated From Their Properties 144

Posted by Soulskill
from the superposition-of-cat-metaphors dept.
Dupple sends word of new quantum mechanical research in which a neutron is sent along a different path from one of its characteristics. First, a neutron beam is split into two parts in a neutron interferometer. Then the spins of the two beams are shifted into different directions: The upper neutron beam has a spin parallel to the neutrons’ trajectory, the spin of the lower beam points into the opposite direction. After the two beams have been recombined, only those neutrons are chosen which have a spin parallel to their direction of motion. All the others are just ignored. ... These neutrons, which are found to have a spin parallel to its direction of motion, must clearly have travelled along the upper path — only there do the neutrons have this spin state. This can be shown in the experiment. If the lower beam is sent through a filter which absorbs some of the neutrons, then the number of the neutrons with spin parallel to their trajectory stays the same. If the upper beam is sent through a filter, than the number of these neutrons is reduced.

Things get tricky when the system is used to measure where the neutron spin is located: the spin can be slightly changed using a magnetic field. When the two beams are recombined appropriately, they can amplify or cancel each other. This is exactly what can be seen in the measurement, if the magnetic field is applied at the lower beam – but that is the path which the neutrons considered in the experiment are actually never supposed to take. A magnetic field applied to the upper beam, on the other hand, does not have any effect.
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More Quantum Strangeness: Particles Separated From Their Properties

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  • by Animats (122034) on Wednesday July 30, 2014 @03:33PM (#47568933) Homepage

    That's a nice result. It's in accord with theory. It doesn't match human intuition based on large-scale objects, but it's the way the universe really works. The theory in this area is well understood; Feynman's "QED" has a good overview.

    Ever since the double-slit experiment [wikipedia.org], it's been clear that this stuff is real. Over the last few decades, more of the weirder predictions of quantum electrodynamic theory have been confirmed experimentally. This is another predicted event confirmed. Nice work.

    • by geekoid (135745)

      "but it's the way the universe really works. "
      at the quantum level. The macro universe is also how the universe really works.

      • It's the way the Universe works at every level, as far as we know. It doesn't just apply to atoms and electrons, but to rocks, people, and planets. Quantum effects occur at the macroscale. Two important examples are lasers and superfluids.

        I know some people are going to say, "But doesn't relativity take over at the scale of galaxies and such? And isn't relativity incompatible with QM" And the answer is: no, they definitely aren't incompatible. In fact most proposals for unified theories have been based on q

      • The macro universe is also how the universe really works.

        Only when it doesn't disagree with the quantum result.

        People used to think that the Earth was the center of the universe, then some allowed that maybe the Sun might be the center of the universe, but really it was always about, and still is, the "me" being the center of the universe.

        The approximations of reality that we sense with our ape-minds is really useful, but far from anything True(tm) or objective. What we feel to be "intuitive" is just a col

    • It's in accord with theory.

      Care to explain how? AFAICS this is a new phenomenon.

  • Strange? (Score:5, Interesting)

    by jandersen (462034) on Wednesday July 30, 2014 @03:36PM (#47568973)

    I'm getting a little bit tired of the never ending fascination with QM 'weirdness', because it seems to me that it tries to see everything as 'weird' simply because it is 'quantum', with the danger that that it makes people blind to what might be explainable by more intuitive means.

    In this case I think we see an illustration of the fact that the notion of a particle as a mathematical point in space - something with zero dimensions - is an abstraction; an approximation that works well enough because we can't in that much detail any way, and it makes the equations so much easier. We have always known, somewhere, that this is not true - things like the mysterious wavefunction that mysteriously collapses as soon as we measure it is a big hint, I would say. As explanations go, that one has always sounded a bit strained - hopefully we will be able to handle the maths of a better model in the not too remote future.

    A more likely scenario, in my view, is that what we call particles is something more distributed in space, and that somewhere in that 'distributed particle' we can explain how a particle can travel through several paths at once. I mean, it isn't even an altogether new observation - the famous electron diffraction experiment shows something similar.

    • by mx+b (2078162)

      I have never been a fan of the quantum "weirdness" either. Everyone gets caught up in the Copenhagen interpretation and Schroedingers' cat and all, and ignores a simpler explanation. I think you may be on the right track with zero dimensions not being realistic -- and I believe that is the hypothesis of string theory actually, to model objects as 1d strings instead of 0d points -- but even that I think is overlooking something easier.

      The Heisenburg uncertainty principle illustrates the true nature, I think.

      • by Anonymous Coward

        This rather sounds like Hidden Variable Theory, and that's been pretty much discredits. Bell's Theorem, I believe it is.

        • Hidden variables are the simplest way to kill a probabilistic model of reality. Like every time I think of quantum theory, I think of the randomness of Brownian motion, how 900 trillion molecules are smacking the pollen under the microscope from the left, 900 million plust 53 from the right, and that 53 is heavy enough to make it move. But luckily, by the time we found the random Brownian motion of lifeless particles, we already had the Maxwell-Boltzmann kinetic theory of gases, and its statistical rules, a
          • And the speed of gravity may indeed be infinite, if it propagates through a medium that's empty, even empty of electromagnetic vacuum. Does that sentence even make sense? It's like saying vacuum has mass per unit volume, that retards gravity, like, if you put electrically charged obstacles in the way of light, such as a zirconia crystal of a fake diamond ring, it will slow light down, so putting a lot of sand or earth or metal in the way of gravity slows it down too? Or does gravity penetrate mass unimpeded
            • As in is there a way to create absolute vacuum, pump out the electromagnetic field, or ether, or whatever you wanna call it? In the days of Toricelli they used to wonder whether absolute metaphysical void is philosophically possible, and the 760mm Hg mercury tube was their prime example of messing with such vacuum, and how it wants to suck on things, nature abhores emptiness, til someone came around and said no, it does not, what we got is atmospheric pressure pushing down on mercury, and vacuum not pushing
              • Of course you can't have a perfect void, but it's quite a stretch to go from "vacuum has a refractive index" to "if it didn't, light speed would be infinite". You're basically saying General and Special Relativity are wrong, as Lorentz Invariance and the Speed of Light (the number, nothing itself to do with light) being the upper bound of velocity that not just the Universe, but Time itself can sustain. At c, time increments by 0. I'm also not including -t (>c) tachyons in that generalization, but they s
                • OK, you're right. So I correct myself: In absolute void the speed of light is not infinite, but just simply does not exist, because it's undefined, 0/0 division, and there is actually no wave at all, because there is no medium to carry it. The speed of any wave is the square root of a driving force term divided by an inertial term, as in sqrt((1/epsilon) / mu) for electromagnetic waves, or sqrt(E/Rho) for mechanical waves, E being the Young modulus, or stiffness (potential energy), rho the mass density (ine
        • by yndrd1984 (730475)
          Technically, Bell's Theorem only rules out local hidden variables.
          • Which is to say, hidden variables that don't violate causality. It's curious that people desperate to preserve causality in the universe like to raise this particular loophole in Bell's Theorem.
            • by yndrd1984 (730475)
              Which is to say, the statement was entirely correct. It's curious how people who are enamored with one interpretation see neutrally stated clarification as desperation.
      • by sconeu (64226) on Wednesday July 30, 2014 @04:25PM (#47569411) Homepage Journal

        Your explanation of Heisenberg with the inability to observe is incorrect. That's a RESULT of Heisenberg.

        Heisenberg's Principle comes out of the wave/particle duality. To localize a particle, you have to add waves of differing frequency to its wave function (ala Fourier). The more you localize it, the more waves of higher frequency you add. Momentum is derived from the wave frequency. Therefore, when you localize a particle, you are increasing the uncertainty of the momentum (by adding more and more higher frequency waves).

        This is the argument that Heisenberg used (yes, I've read his book).

        • by sconeu (64226) on Wednesday July 30, 2014 @04:27PM (#47569433) Homepage Journal

          Follow up to my own post.

          The fact that you cannot measure the momentum and location of a particle exactly is NOT a limitation imposed by measuring apparatus. The fact is that a quantum particle HAS no exact momentum and location, as a result of its wave function.

          • by mx+b (2078162)

            Heisenberg's Principle comes out of the wave/particle duality. To localize a particle, you have to add waves of differing frequency to its wave function (ala Fourier). The more you localize it, the more waves of higher frequency you add. Momentum is derived from the wave frequency. Therefore, when you localize a particle, you are increasing the uncertainty of the momentum (by adding more and more higher frequency waves).

            I understand the mathematics involved in Fourier analysis, but that is the mathematics -- is the electron ACTUALLY doing that, or was that simply a mathematical/logical proof that correlates highly with what we see?

            Follow up to my own post.

            The fact that you cannot measure the momentum and location of a particle exactly is NOT a limitation imposed by measuring apparatus. The fact is that a quantum particle HAS no exact momentum and location, as a result of its wave function.

            Is there an experiment or theorem that shows specifically that it cannot be because of the apparatus? It has been a while since I've taken quantum mechanics, so maybe I am forgetting a theorem or something.

            But my thought is: Until we measure something, I'm not sure how anyone can really say wheth

            • by DrJimbo (594231) on Wednesday July 30, 2014 @07:19PM (#47570815)

              I understand the mathematics involved in Fourier analysis, but that is the mathematics -- is the electron ACTUALLY doing that, or was that simply a mathematical/logical proof that correlates highly with what we see?

              ISTM your question is meaningless. The best we have to offer on what the electron is ACTUALLY doing is with mathematics that correlates highly with what we see. I don't know what it means for there to be an actuality beyond that.

              Even your question/remarks on the "correct conceptual framework" seems to miss the mark. The best we have there is the simplest mathematics that correlates highly with what we see.

              All of this mathematical physics has its root in formulas that were derived based on data collected in labs, ..

              Actually, a very big part of the theory is predicting new and unexpected results that have not been seen in the lab yet. Another big part is when the same mathematics can describe different phenomenon that were previously thought to be unrelated. Lee Smolin provides an excellent description of how this all works in his book The Trouble with Physics. I highly recommend it.

              • I hate this point of view - the one that says our math is everything, and there's no objective reality underneath driving it all. The math absolutely has to match observations, but describing physics without trying to understand what's ACTUALLY happening is like describing a baseball game purely in terms of Newtonian interactions. You'll understand individual phenomena very well, but you'll never understand the model well enough to make accurate predictions.

                • I get what you're saying, and even agree with the general point, however, QED for the last half century has been pretty much on a roll of confirming that the math is as close to reality as we can get. There are pretty strong proofs for a lot of bizarre mathematical concepts (wave-function collapse of things larger than bosons, non-locality in entanglement). It appears that the Universe is in fact some kind of bizarre mathematical model, perhaps that we perceive through our limited Einsteinian relativistic s
                • by DrJimbo (594231)

                  In addition to what DamnOregonian said, there is another problem with this quest to know what is ACTUALLY happening. For almost all people who voice this desire, "what is ACTUALLY happening" means a model That matches their intuition based on the non-relativistic 3+1 dimensional, classical world of their senses. This ain't gonna happen.

                  Maybe you misunderstand what the models in theoretical physics actually do. You say we will never understand the models well enough to make accurate predictions. Wh

                  • I think my biggest problem was the phrase "ISTM your question is meaningless". It reinforced my general impression that a lot of physicists treat the math as the be-all-and-end-all of physics, without trying to develop an overarching (for lack of a better word) "narrative".

                    You end up with statements like "going faster than c makes you travel backwards in time" or "an electron doesn't have a position until it's measured". Both fit the math, but are probably simplifying things greatly. I suspect the physic

                • What do you mean by "what's ACTUALLY happening"? We've got darn few ways to observe things that happen on this scale, and elementary particles and their combinations behave considerably differently from the scale of the universe we're most familiar with. Electrons behave very differently from charged baseballs, and trying to explain electrons in terminology suitable for baseballs is not productive.

                  In the meantime, there's quantum phenomena that we inherently can't observe directly. We can measure the

            • is the electron ACTUALLY doing that, or was that simply a mathematical/logical proof that correlates highly with what we see?

              Ummm. physics has been all about testing for discrepancies [youtube.com] between the two for at least a century now. There's a nobel prize waiting for anyone who can show an electron not behaving itself in accordance with the standard model.

        • Your explanation of Heisenberg with the inability to observe is incorrect. That's a RESULT of Heisenberg.

          Cause and Effect? I'm pretty sure Heisenburg simply describes the effect, not causes it :-)

        • by BranMan (29917)

          "This is the argument that Heisenberg used (yes, I've read his book)."

          Fine. But did you read it in the original Klingon?

      • Re: (Score:1, Insightful)

        by Anonymous Coward

        What you're describing is incorrect. The particle *actually* behaves as if it is two places at once - including things like interfering with itself.

        However, if you want an interpretation that seems more "intuitively correct" than the Copenhagen interpretation, I like Cramer's transactional interpretation of quantum mechanics [wikipedia.org]. It avoids any "magic" and sticks with a single universe; it does, however, introduce zero mass transaction particles going at the speed of light backwards in time. Assuming relativi

        • by mx+b (2078162)

          What you're describing is incorrect. The particle *actually* behaves as if it is two places at once - including things like interfering with itself.

          I recall in classical electromagnetism class having to calculate the effects of the electric field of an object ON ITSELF as the particle was moving. I do not think strictly speaking it has to be a "weird" quantum effect if we had to do similar things in classical calculations. Are you aware of an argument on why it *must* be in two places at once, rather than simply seeming that way because of its interactions while moving (or interactions with nearby particles, which move and therefore change the potentia

      • by TheCarp (96830)

        > I have never been a fan of the quantum "weirdness" either. Everyone gets caught up in the Copenhagen
        > interpretation and Schroedingers' cat and all, and ignores a simpler explanation.

        Ignores? I am a lay observer but I have yet to see one that actually explains.

        > when single particles are allowed thru, we see only single points on the detector.
        > It is only when a flood of electrons are allowed that we see an interference pattern similar to that of a wave.

        Wrong. when single particles are allowe

        • by mx+b (2078162)

          Wrong. when single particles are allowed through a single path yes. However, if multiple paths are available even a single particle interferes with itself. Take enough samples of a single particle going through with multiple paths, and you get an interference pattern: http://en.wikipedia.org/wiki/D... [wikipedia.org]

          I perhaps wasn't as careful with my language as I should have been. But even the article you link to says that you release more than one particle. It is one at a time, not perhaps the "flood" I stated (though I was thinking of a large number of electrons more so than time frame). But it is *more than one* particle, so I am not sure how this can be called "self-interference" with a single particle when other particles have already gone thru the apparatus.

          If we could carefully release a SINGLE electron, and w

          • The electrons are being run through the experiment one at a time, so they can't be interfering with each other. There is no "electron build up"; even if you tore the apparatus down and rebuilt it from scratch each time, guaranteeing that there was no leftover state from previous experiments, you'd still get the same results.

            You only get one discrete "hit" per electron, but the location varies according to some statistical distribution—and that distribution, measured over a series of single-electron ex

          • by DamnOregonian (963763) on Wednesday July 30, 2014 @11:27PM (#47571957)
            Multiple electrons sent serially.

            The interference pattern emerges in spite of a conga line of electrically unconnected electrons, sent one at a time at a double-slit interface to the detector. Leptons, not bosons. Things with *rest mass*. Volume. Real shit, not just light, is *actually* a wave-function.

            It's the most fucking bizarre thing in the Universe that I'm aware of, and upon learning of the single-electron version of the experiment, I finally realized that what we perceive of the universe isn't anything close to what it really is. We are little circles in a flat universe trying to perceive spheres passing through our planes of perception, or something that our evolved senses have similarly not equipped us to grok.
            • by Melipone (1458593)
              I wish I could vote this comment up - you've hit the nail on the head.
            • I like to think of an electrons a droplet of water (well, droplet of EM-field) with some very exotic properties.


              • It tends to stick together, but can be pulled apart.

              • When an electron is pulled apart (forced through a double-slit, for instance), it's strongly self-attracted, and tries to spring back into an electron-sized droplet very quickly

              I think there's a very good reason electrons bound to an atom act like an "electron cloud". It's not that the electron appears and jumps randomly, it's actually everywhe

      • by Anonymous Coward on Wednesday July 30, 2014 @05:06PM (#47569787)

        Particles can't really be two places at once.

        And here you are completely wrong. Finiteness of the universe disagrees.

        The double slit experiment mentioned by another poster shows this is the correct interpretation too. As you can see from the photos on Wikipedia, when single particles are allowed thru, we see only single points on the detector. It is only when a flood of electrons are allowed that we see an interference pattern similar to that of a wave

        You are wrong again. Stop. Double slit experiment has been duplicated using *individual photons*. Yes, one photon fired at detector at a time. ONE. No more, just ONE. After waiting sufficiently long, interference pattern was produced on the detector. The photon appears to have interfered with itself.

        http://www.animations.physics.... [unsw.edu.au]

        • by mx+b (2078162)

          And here you are completely wrong. Finiteness of the universe disagrees.

          I am not sure what "finiteness of the universe" means in this context. Could you elaborate why that immediately says particles must be in two places at once?

          You are wrong again. Stop. Double slit experiment has been duplicated using *individual photons*. Yes, one photon fired at detector at a time. ONE. No more, just ONE. After waiting sufficiently long, interference pattern was produced on the detector. The photon appears to have interfered with itself.

          The photon does appear to interfere with itself, but only after sufficient time. Is it really interfering with ITSELF? The experiment description on the page you link to says that photon is absorbed by an atom to knock off an electron, which starts an avalanche, and we read the resulting current as a detection. Now, the original photon has been absorbed

          • by Anonymous Coward

            The photon does appear to interfere with itself, but only after sufficient time. Is it really interfering with ITSELF? The experiment description on the page you link to says that photon is absorbed by an atom to knock off an electron, which starts an avalanche, and we read the resulting current as a detection. Now, the original photon has been absorbed, however, anytime an electron accelerates it releases radiation (brehmsstralung). So it actually sounds like the photon is causing (a) a current to form, and (b) extra photons to be emitted by the electrons as they bounce around. The new photons scatter in random directions to be sure, but some of them must make it back into the apparatus, bounce around, and come back to the detector, producing a new pattern. Eventually this will settle down as the electrons and photons lose energy over time, but it happens long enough to produce a pattern.

            So I don't really see how the original photon interfered with itself; it appears that multiple photons were generated and recorded, and as energy is lost, these waves overlap differently and produce a pattern.

            This is my interpretation and I am glad to say I am wrong if provided with some evidence that shows we can rule this possibility out.

            No, the photon goes out of the emitter. The photon goes through double slits. The photon hits detector. The photon-to-electron conversion happens in the detector. There is no photons emitted out of the detected that "bounce around". If it were, there would clearly be a noise floor, never mind other abnormalities (like detectors not actually working!)

            1. ONE photon emitted
            2. photon detected at spot A
            3. time passes - nothing detected
            4. ONE photon emitted
            5. photon detected at spot B
            6. wait
            7. repeat for a while
            8

        • Double slit experiment has been duplicated using *individual photons*. Yes, one photon fired at detector at a time. ONE. No more, just ONE. After waiting sufficiently long, interference pattern was produced on the detector. The photon appears to have interfered with itself.

          I too, er, interfere, with myself when I'm alone after waiting sufficiently long.

      • by geekoid (135745)

        Reading both your post is like watching dogs try to explain airplanes.

      • by Zalbik (308903) on Wednesday July 30, 2014 @05:25PM (#47569955)

        Particles can't really be two places at once. But since we're knocking things around with our light beam, we can't say for sure where it is now -- so we instead talk in terms of probabilities of where the electron is, rather than saying matter-of-factly where it is. This is what quantum mechanics does, it calculates probabilities that the electron is in a certain place, probability it was going a certain speed, etc.

        As others have mentioned, you are missing a couple of fundamental points of the double-slit experiement.

        1) The pattern observed has nothing to do with the photons being hard to measure (classically photons are sent through the slits),
        The pattern produced is exactly the interference pattern expected if light were actually a wave. The peaks and troughs of the two waves cancel each other out which results in the dark bands. Dual peaks or dual troughs reinforce each other, resulting in bright bands.

        2) If this was a result of electric field build up and the "detector knocking particles around a bit", then it should also happen for a single slit (it doesn't). It also should not occur for photons (electrically neutral), but it does.

        3) "when single particles are allowed thru, we see only single points on the detector"

        This is incorrect, and the weirdest thing about the experiment. If two slits are opened, and particles are sent through one at a time, there is still the same interference pattern created. Individual particles behave as if they do not have a fixed location, but only a probability of existing at a specific location.

        Heisenberg's principle is a result of quantum mechanics and wave-particle duality, not the cause.

        • Just to up the ante on the weirdness: http://en.wikipedia.org/wiki/D... [wikipedia.org]
          The interference pattern can be destroyed, seemingly retroactively (if one doesn't accept superposition). Not many people are willing to accept particles with wave-functions measurable with interferometry (up to buckyballs, I believe) will go back in time and and alter their flight characteristics. The Universe really is quantum. And fucking weird.
      • by Khashishi (775369) on Wednesday July 30, 2014 @05:33PM (#47570027) Journal

        IAAPhysicist. Parent isn't correct. I advise you to not worry too much about what is "real" and accept that physics looks for simple models which match our experiences. You need to think abstractly, and assume less. For example, everyone grows up with some intuition of what an object is, and then project that notion into realms where they don't apply. The letters on this webpage, for example.... These are black objects which move up and down when you scroll the page. Or, is it really the white spaces between the letters which are the real objects, and the black is just void? Actually both are wrong, and the "reality" is that your monitor is doing certain things, depending on how deep you want to look.

        When physicists talk about a particle, they are talking about the smallest step in the amplitude of the fluctuation in some field or combination of fields. A fluctuation doesn't have to be purely one kind of field; for example, a phonon is made out of collective motions of atoms, and polaritons are sort of some mix of photon and phonon. These could be considered particles (but not fundamental particles). This isn't the only way to think about a particle (since it's all just a model anyways), but it is more accurate than billiard balls.

        Heisenburg uncertainty principle exists because you are trying to pinpoint a fluctuation in fields which occupy all space.

        Parent's description of the double slit experiment is fully wrong. Electrons do not interfere with some build up of electrons. Electrons interfere with themselves, because the fluctuation (which is the electron) exists in the full region between the source and screen. The interference pattern is the same no matter how slowly (in terms of electron rate) you fire the electrons, so build up is not a concern. A similar interference pattern exists in photons and neutrons as well, which aren't charged.

        • IAALawyer: I don't like your still hard-to-understand description. We passed a law to make PI exactly 3, right? Well, let's pass one that makes a particle that sits exactly THERE with absolutely no movement. Case closed.

          So, where do I go pick up my Nobel prize?


          PS - I am NOT really a lawyer, but I stayed at a Holiday Inn last night.
          • by Khashishi (775369)

            This isn't a perfect analogy, but think of a kink in the carpet. You can push it around, like a object, but you can't make it disappear without taking out some slack in the carpet. Now if we define this kink as a particle, it IS a particle. Using this definition, the particle doesn't have a precise position, nor a rigid shape. But a quantum particle isn't at all like a classical big object, which still has a precise position although it is extended over space. The difference is that a quantum particle appea

        • by jcdr (178250)

          I lost a opportunity to moderate you insightful (you already got a 4 anyway) to take a chance to say thank you very much for your explanation. Your second paragraph is just so clear and simple. I think that I have understand a new aspect of the physic in a minute. Great.

          Sometimes a simple phrase open a mind so quickly that I wonder how fast we can progress is we got the chance to read a lot of them...

        • Electrons interfere with themselves, because the fluctuation (which is the electron) exists in the full region between the source and screen. The interference pattern is the same no matter how slowly (in terms of electron rate) you fire the electrons, so build up is not a concern.

          And this is an important point. I'm not a physicist, but one thing that helped me understand this better is to consider firing a single electron (for example) at the two slits one at the time. It could be at the rate of one per mi

      • Interference is also noticed in The Double Slit Experiment with single photons and other particles spaced seconds apart. They do interact with themselves. It really is weird.
      • mx+b - I used to think, as you did. Then I read this. - http://quantumtantra.com/bell2... [quantumtantra.com] - and then I still didn't believe it. So, as a computer programmer, I tried to make a program that would mock what was happening. My theory was if I could model it in code, then it wasn't spookiness. Well, after trying for a few days, I couldn't do it. I realised the *only* way I could make my program work, would be to make the emulated particles in my program communicate with each other..... which means one of
      • There are wavepacket objects that can be knocked around. I forget, but I think the word is soliton, or something similar, a single wave-hump, or a wavehump plus some fast decaying amplitude fluctuations a couple wavelengths away, that travels, as if it were a particle. In order to understand quantum "particles" I think they need to delve into the math of ping pong-ing macroscopic single hump wave "particles" around - how they interact with each other, how to get a bounce out of each. Another thing that acts
        • By the way, I forgot to add, that it amazes me how every galaxy is flat, or most of them are, and I can't really picture gravity keeping together a centrifugal balanced spherical galaxy, there is no way to have the rotations, and if there is, there'd be a lot of collisions. Like in outer space conquest by humans most of the space stations will have to get in line with the general flow of things, and stay in the flat orbit plane of the Sun, but just like Earth satellites, it's possible to go North-South as o
        • Also, I seen a youtube video of a weird fluid, which under oscillations that resupplied the energy lost to friction, it grew tentacles, standing waves on its surface. Then you can ping ping these waves around.
    • by Rockoon (1252108)

      In this case I think we see an illustration of the fact that the notion of a particle as a mathematical point in space - something with zero dimensions - is an abstraction; an approximation that works well enough because we can't in that much detail any way, and it makes the equations so much easier.

      All that we ever really measure after all is interactions (not exactly the same as 'forces' but 'force' is the macroscopic equivalent.) Both the notion of particles as either something with zero dimensions, something with many dimensions, or perturbations in some theoretical 'field' is an abstraction.

      Take the leptons such as the electrons. In our observations we frequently take several interaction measurements of 'an electron' that together happen to be consistent with a mathematical description of a 'di

      • Well, it's a label to describe an indivisible quanta of an interaction that we observe.
        The electrical field wasn't always believed to have a discrete resolution (the electron).
    • by jrumney (197329)
      The only thing that is strange is the confusing terminology that is counter to its standard meaning. "spinning in parallel to its trajectory." and spinning in the opposite direction is somehow not parallel with the trajectory... yep, you lost me there, you boffins must be so much smarter than us mere engineers.
    • by Livius (318358)

      I continue to find quantum weirdness very cool and very weird, but I find too often that it's acquired a quasi-celebrity status and people stop thinking as soon as they hear 'quantum'. Quantum weirdness is not the only way for things to be cool and/or weird.

      None of the experiments with photons, for example, demonstrate quantum weirdness - they all demonstrate special relativity weirdness, which is completely different. (Remember that the photon, in its own frame of reference, always travels zero distance

    • by JoeSilva (215173)

      Solitons, or at least soliton-like equations. That's my bet.

      Einstein was working in that direction but the math for non-linear equations was not up to it back then and even now it's not clear exactly what set of non-linear equations, in three space dimensions + time + whatever else, gives Solitons that behave exactly like the observations. Also from what I have read he was not taking into account the strong and weak nuclear forces. Plus back then quarks were unknown?

      Perhaps string theory is another sort of

    • by Sanians (2738917)

      I once read an explanation of the dual slit experiment that made a hell of a lot of sense to me. Granted, I don't know much about this shit and so how much sense it makes to me isn't a terribly useful metric, but here it is:

      Basically, IIRC, the experiment was set up so that they could allow single electrons through the slits at once and they observed that if they recorded their positions over time, they still obtained the diffraction pattern that was seen when many electrons were present, and so the electr

  • by sinij (911942) on Wednesday July 30, 2014 @03:39PM (#47568997) Journal
    This is optimization error in the compiler of our simulated universe.
  • by enharmonix (988983) <enharmonix+slashdot@gmail.com> on Wednesday July 30, 2014 @03:51PM (#47569117)
    I'm not exactly sure I followed what happened, and I read the dumbed down version. I don't see how this isn't an extreme case of superposition, but I'm not clear on what they did. They split a stream of neutrons into an upper beam with spin going forward and a lower beam with spin going backward. They did stuff to the lower beam that didn't happen to the upper beam? And it keeps mentioning recombining the beams but I didn't quite catch what profound result that had. Can somebody who follows this please explain it?
    • by parallel_prankster (1455313) on Wednesday July 30, 2014 @04:09PM (#47569303)
      This is what I understood. They first split the beams into upper and lower paths and filtered out the neutrons from the lower path using their spin state . They double checked this by using limiting/filtering neutrons on one of the paths each time and measuring the number of neutrons after re-combining and filtering out the lower path. This way they made sure that the neutrons coming out after re-combining and filtering must have taken the upper path. Then they applied magnetic field on both paths. But it seems like the neutrons which supposedly could only have come from the upper path had been affected by magnetic field from the lower path. This implies as if their "positions/mass" took one path while their spin took another?
      • Now that I understood. I am actually a little interested to see what kinds of experiments they do along these lines. It seems like string theorists might actually have the opportunity to predict behaviors that the standard model cannot. Unless it just ends up being some previously unknown new elementary bosons... but we already got Higgs. Do we really need more elementary bosons?
      • by steelfood (895457)

        Then they applied magnetic field on both paths.

        They applied the magnetic field to each path separately. They saw no change when the magnetic field was applied to the upper path, but they saw a change when it was applied to the lower path.

        The way you state it, it's a bit confusing as to what they actually did with the magnetic field.

      • Why combine the beams to see which path the neutrons took? Why not measure them individually? Because then you don't get the self-interference effects of the electron double-slit experiment. If you block either hole, it's easy to see that each electron wave-packet went through the other one. But if you keep both holes open, each wave-packet electron goes through both holes, and arrives at the screen in a self-diffraction pattern, with highs and lows in probability or abundance amplitudes. I.e., the modeling
    • by mx+b (2078162)

      It's hard to say without the actual paper, but I think I follow what they did.

      I interpreted it to mean parallel (forward or back actually), vs the lower beam being opposite (so perpendicular to the field). If they applied a stronger magnetic field to the top, when the two beams recombined and filtered parallel, they got exactly what the expected -- same amount of neutrons as top beam, nothing weird. When they applied a stronger field on the lower beam, and recombined and filtered parallel, then they got amp

    • You're not the only one. I've studied particle physics for some time now and that summary was gibberish! I will go read the paper and see if it is any easier to follow. The broken and horribly constructed English isn't helping either!
    • by multimediavt (965608) on Wednesday July 30, 2014 @04:27PM (#47569431)
      The abstract from the Nature Communications article is easier to read and understand what they've accomplished:

      From its very beginning, quantum theory has been revealing extraordinary and counter-intuitive phenomena, such as wave-particle duality, Schrodinger cats and quantum non-locality. Another paradoxical phenomenon found within the framework of quantum mechanics is the ‘quantum Cheshire Cat’: if a quantum system is subject to a certain pre- and post-selection, it can behave as if a particle and its property are spatially separated. It has been suggested to employ weak measurements in order to explore the Cheshire Cat’s nature. Here we report an experiment in which we send neutrons through a perfect silicon crystal interferometer and perform weak measurements to probe the location of the particle and its magnetic moment. The experimental results suggest that the system behaves as if the neutrons go through one beam path, while their magnetic moment travels along the other.

      • Here's a question. What would happen if the beams traveled different distances? AKA, one beam took longer to reach the recombinator than the other. I can guess, but I have no clue about Quantum Mechanics.

        • Here's a question. What would happen if the beams traveled different distances? AKA, one beam took longer to reach the recombinator than the other. I can guess, but I have no clue about Quantum Mechanics.

          So, go read more about the subject in your free time. There are s of freely available publications that cover the topic. I am not certain that the experiment would yield anything based on your hypothesis, not even the results being discussed. The most quantum experiments are predicated on a very specific set of conditions and why it hasn't been done before, accurately.

  • my BIOS has enigmatic quirks.

  • in the hope that this might provide them with yet another way of separating the public from their properties (especially money).

  • Dupe? (Score:5, Informative)

    by Brucelet (1857158) on Wednesday July 30, 2014 @04:14PM (#47569337)
    This was on here 6 months ago [slashdot.org] when the preprint [arxiv.org] hit arxiv.
  • It's a good example for life.
    Take the high road and nothing can affect you.

  • Sounds like a bug in the Matrix to me. It will probably be fixed in the next release.

    • by Tablizer (95088)

      Sounds like a bug in the Matrix to me. It will probably be fixed in the next release.

      No, the Matrix learned from Microsoft: you don't have to fix anything if you have no competition.

    • by CaptnZilog (33073)

      It's easy to fix, all you have to do is reverse the polarity of the neutron flow and you'll save the day.

  • First: when we have established a universal law, and something obeys that law, it is not strange. Two: when you assert that something flies against intuition, you'd better ask some gradeschool kids first. Mine called the author an idiot. (They're 8 and 10.) Three: if someone's experiment results in the observation of a well known, well documented, scientifically named phenomenon, (superposition,) it is rude to call it "more." Or "new." Just rude.
    • First: when we have established a universal law, and something obeys that law, it is not strange.

      Strangeness is a subjective quality.

      The laws themselves are strange to the majority of people because they run counter to everyday experience, therefore things that obey those laws also appear strange.

      Two: when you assert that something flies against intuition, you'd better ask some gradeschool kids first. Mine called the author an idiot. (They're 8 and 10.)

      Then they probably didn't understand the experiment, or you explained it just poorly enough to get the response you wanted for your Slashdot post to make it look all clever and stuff.

      Three: if someone's experiment results in the observation of a well known, well documented, scientifically named phenomenon, (superposition,) it is rude to call it "more." Or "new." Just rude.

      This goes beyond "simple" superposition, and is indeed a new phenomenon.

  • So they split a beam based on the spin, then applied a magnetic field that would shift the spin from down to up, either on the particles that already had spin up or on particles that had spin down... and AMAZINGLY only the latter had any effect on the spin. And they also put a blocking filter either on the particles that had spin up, or on the particles that had spin down... and AMAZINGLY only the former reduced the number of particles with spin up. Truly mind-boggling, this quantum stuff.

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