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posted by martyb on Thursday June 11 2015, @10:15AM   Printer-friendly
from the will-this-help-me-win-the-lottery? dept.

A team in Australia turned thought experiment into lab reality by using lasers. Their subject matter was not a photon but a helium atom. The lasers they used served as a pair of grates, one before the other, with the second grate randomly dropped in.

What they found is weirder than anything seen to date: Every time the two grates were in place, the helium atom passed through, on many paths in many forms, just like a wave. But whenever the second grate was not present, the atom invariably passed through the first grate like a particle. The fascinating part was, the second grate's very existence in the path was random. And what's more, it hadn't happened yet.

In other words, it was as if the helium particle "knew" whether there would be a second grate at the time it passed through the first.

More here: http://secondnexus.com/technology-and-innovation/physicists-demonstrate-how-time-can-seem-to-run-backward-and-the-future-can-affect-the-past/

Also covered at: phys.org. An abstract is available; full report is pay-walled. The original news article is at Australian National University


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  • (Score: 4, Funny) by Justin Case on Thursday June 11 2015, @10:35AM

    by Justin Case (4239) on Thursday June 11 2015, @10:35AM (#194910) Journal

    Just when you think you understand quantum, that counts as an observation so reality fluctuates to make it crazy again.

    What's actually happening here is the helium particle is controlling the random generator. When the helium happens to be a wave, the random generator will draw "two grates" but if the helium is a particle, it will prevent the second grate.

    Now, was that so hard?

    • (Score: 2, Interesting) by Anonymous Coward on Thursday June 11 2015, @12:22PM

      by Anonymous Coward on Thursday June 11 2015, @12:22PM (#194924)

      maybe the universe is a static object?

      Like a huge multidimensional work of art, that's made of all the possible timelines of all the possible universes,
      hanging on what passes for a wall in some higher dimensional analog of Louvre :)

      • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @02:44PM

        by Anonymous Coward on Thursday June 11 2015, @02:44PM (#194962)

        Exactly. God created a static but very complex universe. We are mere bugs in intellectual comparison. To us, it seems dynamic and unpredictable at the edge of our limited understanding. To Him, it is like a simple algebraic formula. He knows all the possible inputs and their corresponding outputs. The only variable in the equation is Mankind. This is how and why I believe in predetermination and free-will at the same time. He knows every possible choice we can make and the outcome of those choices. Its all been iterated in His mind...and the equation was designed to always output, sooner or later, the answer He desires. 42, maybe? Who among us can truly know? Our free-will determines the route. There are many routes but only two destinations: Renewal and Destruction.

        • (Score: 2) by Zinho on Thursday June 11 2015, @02:53PM

          by Zinho (759) on Thursday June 11 2015, @02:53PM (#194966)

          I think I'm having a Poe's Law moment. Are you that guy from Time Cube?

          --
          "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
        • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @03:00PM

          by Anonymous Coward on Thursday June 11 2015, @03:00PM (#194971)

          I think Christianity (depending on denomination) teaches that while the future is predetermined we still have free will. The way I heard it taught is that just because we have no control of our past doesn't negate the fact that we have/had free will to do what we do/did. We're still responsible for what we did. The future is simply the past of a more distant determined future. God already knows the future because he knows how we will act under all possible conditions, he knows what future conditions will come to pass, but this doesn't change the fact that it is we that voluntarily chose/choose how we wish to act under these conditions. I believe the doctrine is called divine providence.

          • (Score: 4, Interesting) by FreeUser on Thursday June 11 2015, @03:31PM

            by FreeUser (5423) on Thursday June 11 2015, @03:31PM (#194993) Homepage

            I think Christianity (depending on denomination) teaches that while the future is predetermined we still have free will.

            Like nearly all religious doctrine, it's full of doublespeak and riddled with cognitive dissonance designed to force a believer into accepting two sides of a contradiction at the same time and thus undermining their ability to think (or argue against the point) clearly (or sometimes at all).

            What they're really saying boils down to is:

            "Your fate is predetermined. You have absolutely no control over it, but we're going to tell you that you do, so you're consumed with guilt, and we're going blame you for everything you have no control over anyway, so you better throw yourself on our (deity's) mercy and maybe, just maybe, you won't burn in hell forever, but you probably will, because god loves you!"

            One of the classic ways to brainwash, disrupt, or otherwise attack a person's ability to reason is to try and force them to believe two contradictory things at the same time. What is interesting is, depending on the level of emotional investment, the lengths to which people will go to turn themselves into intellectual pretzels to do just that.

            --
            The Future of Human Evolution: Autonomy, a Novel
            • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @03:43PM

              by Anonymous Coward on Thursday June 11 2015, @03:43PM (#195009)

              I love the 'intellectual pretzel' analogy!

            • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @04:18PM

              by Anonymous Coward on Thursday June 11 2015, @04:18PM (#195017)

              Like nearly all religious doctrine, it's full of doublespeak and riddled with cognitive dissonance designed to force a believer into accepting two sides of a contradiction at the same time and thus undermining their ability to think (or argue against the point) clearly (or sometimes at all).

              And what makes you so confident that everything fits nicely and neatly into your view? This universe does seem to have its fair share of "two sides of contradiction at the same time".

              So just because you believe the "free will vs knowing the future stuff" is contradictory doesn't mean that you are right.

              The apparent results of this experiment is more data indicating that things are not all that simple. If you believe in the scientific method, you should be willing to challenge your beliefs given new data. Perhaps the experimenters made a mistake or they misinterpreted the results, so I'd wait till it's confirmed by others.

              But so far, this universe isn't so "neatly simple", thus if it really has a Creator, it would be really stupid to assume that the Creator is as simple as many of those silly philosophers/logicians like to assume[1].

              [1] A lot of what they do is as stupid as the Ghosts in Pacman assuming the Creator(s) of the Pacman game are as simple or even simpler than the game itself. And using the Pacman game logic to prove the nonexistence of a Creator of the Pacman game is even stupider.

              Arguments that the Creator if he does actually exist doesn't really care that much about those in the game, do seem a fair bit more tenable.

              • (Score: 3, Informative) by Anonymous Coward on Thursday June 11 2015, @04:34PM

                by Anonymous Coward on Thursday June 11 2015, @04:34PM (#195023)

                That's a Deist argument, not a Christian one. I hate how Christian apologists constantly make Deist arguments and then switcheroo in ol' Yahweh when they think no one's looking. It's dishonest as hell and if there *were* a good and just God that took realtime interest in human affairs those people would burst into flames at the podium when they did it.

                • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @06:23PM

                  by Anonymous Coward on Thursday June 11 2015, @06:23PM (#195080)
                  uh I did already say: "Arguments that the Creator if he does actually exist doesn't really care that much about those in the game, do seem a fair bit more tenable."

                  tldr; "even if a creator exists, the evidence is that he doesn't really care that much or he's an asshole" angle works better vs Christianity than the "contradiction" angle.
                  • (Score: 2) by DECbot on Thursday June 11 2015, @07:38PM

                    by DECbot (832) on Thursday June 11 2015, @07:38PM (#195114) Journal

                    tldr; "even if a creator exists, the evidence is that he doesn't really care that much or he's an asshole"

                    I think you're on to something...

                    1. Create a universe where multiple contradictions can exist.
                    2. Make the inhabitants of that universe worship you or suffer divine punishment.
                    3. Make them feel guilty for questioning the contradictions.
                    4. Make sure that they will suffer during their life, but tell them that you love them.
                    5. ???
                    6. Profit!!!
                    --
                    cats~$ sudo chown -R us /home/base
              • (Score: 0) by Anonymous Coward on Monday June 15 2015, @06:45PM

                by Anonymous Coward on Monday June 15 2015, @06:45PM (#196608)

                So just because you believe the "free will vs knowing the future stuff" is contradictory doesn't mean that you are right.

                If you can know the future, that means it is pre-determined, if it is pre-determined you cannot have free will to make choices. If you wish to argue otherwise you are trying to define "free will" to mean something other than what it does. It really is that simple.

                Personally I don't believe in free will, as we are in essence just incredibly complicated machines. If you believe we can have free will you must logically believe a single die can have free will over which number it will land on when you throw it. You might try to claim we are different, but other than in terms of complexity, how are we? At what point on the evolutionary tree did we acquire free will?

                Now whether the universe is deterministic or not is a different question. As although a deterministic universe prevents free will, the universe being non-deterministic doesn't mean we can or do have free will. And we don't know how the universe works well enough at a fundamental level to know whether or not the universe is deterministic.

            • (Score: 3, Interesting) by curunir_wolf on Thursday June 11 2015, @04:49PM

              by curunir_wolf (4772) on Thursday June 11 2015, @04:49PM (#195032)

              Spirituality has little to do with the physical world. Like quantum mechanics, it seems like paradox when viewed logically. But logic fails to convey the universal truths in the unseen. Your brain cannot even understand your brain - only a scaled down model of it. Likewise the ephemeral interconnections of all matter and energy. So - it is taught in paradoxes to the uninitiated, paradoxes that your mind cannot reconcile, like an Escher painting, until you give up on recording and analyzing your observations, and instead let the experience flow through you.

              It is the pinnacle of difficulty to impart a personal viewpoint of something that cannot be explained to another person through our crude symbolic language. But there are techniques that can lead others to enlightenment. Most of them use paradoxical lessons.

              --
              I am a crackpot
              • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @05:24PM

                by Anonymous Coward on Thursday June 11 2015, @05:24PM (#195047)

                Your signature never was so appropriate than right now.

              • (Score: 0) by Anonymous Coward on Friday June 12 2015, @04:29AM

                by Anonymous Coward on Friday June 12 2015, @04:29AM (#195269)

                >But logic fails to convey the universal truths in the unseen.

                *Some* of them.

                >Your brain cannot even understand your brain - only a scaled down model of it.

                Oh I think we're making great strides [newscientist.com] in that direction.

                >it is taught in paradoxes to the uninitiated, paradoxes that your mind cannot reconcile

                To tread the sharp edge of a sword,
                To run on smooth-frozen ice,
                One needs no footsteps to follow.
                Walk over the cliffs with hands free.

                I see no paradox here. Nor anything to reconcile. Seems rather clear cut.

                >It is the pinnacle of difficulty to impart a personal viewpoint of something
                >that cannot be explained to another person through our crude symbolic language.

                Difficult? yes. I take issue with "crude" though. The Blue Cliffs are most beautiful no?

              • (Score: 0) by Anonymous Coward on Saturday June 13 2015, @04:12AM

                by Anonymous Coward on Saturday June 13 2015, @04:12AM (#195639)

                Who the fuck modded this up? Mod this motherfucker down! And you lot laugh at Kansas City School Board? It's you fucktards that keep pseudoscience quacks in business..

            • (Score: 1, Funny) by Anonymous Coward on Thursday June 11 2015, @10:01PM

              by Anonymous Coward on Thursday June 11 2015, @10:01PM (#195162)

              One of my friends once told me what amounts to "I don't know how magnets work, therefore as a species we don't know how magnets work, therefore God."

    • (Score: 2) by acid andy on Thursday June 11 2015, @03:28PM

      by acid andy (1683) on Thursday June 11 2015, @03:28PM (#194990) Homepage Journal

      That actually sounds more plausible than time travel. I'd be wanting to know exactly what random number generator they are using and what happens if they change it to a different one or even a pseudorandom number generator.

      --
      If a cat has kittens, does a rat have rittens, a bat bittens and a mat mittens?
  • (Score: 3, Funny) by No Respect on Thursday June 11 2015, @10:56AM

    by No Respect (991) on Thursday June 11 2015, @10:56AM (#194912)

    The reason they just found chimps in the wild drinking alcohol is because Planet of the Apes comes true in the distant future!

    • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @12:20PM

      by Anonymous Coward on Thursday June 11 2015, @12:20PM (#194923)

      Damn You!! Damn You All!!

      • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @02:46PM

        by Anonymous Coward on Thursday June 11 2015, @02:46PM (#194964)

        I hate every ape I see, from chimpan-a to chimpan-z!

        • (Score: 1) by TWX on Thursday June 11 2015, @04:44PM

          by TWX (5124) on Thursday June 11 2015, @04:44PM (#195026)

          Sung to the tune of the Tootise Roll commercial jingle?

          Sounds like a stage adaptation by Matt Stone and Trey Parker.

          --
          IBM had PL/1, with syntax worse than JOSS...
          and everywhere the language went, it was a total loss.
          • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @07:45PM

            by Anonymous Coward on Thursday June 11 2015, @07:45PM (#195119)

            Simpsons I believe.

  • (Score: 2, Interesting) by splenolymph on Thursday June 11 2015, @11:40AM

    by splenolymph (5495) on Thursday June 11 2015, @11:40AM (#194916)

    Matter experiences time. Photons don't. Their 'Now' is forever and over in less than an instant. We experience time so we interpret the photon's behavior from that point of view.

    • (Score: 2, Touché) by Anonymous Coward on Thursday June 11 2015, @01:04PM

      by Anonymous Coward on Thursday June 11 2015, @01:04PM (#194934)

      Yeah but this was with helium. Last time I checked, helium was actually quite massive.

    • (Score: 2) by threedigits on Friday June 12 2015, @08:41AM

      by threedigits (607) on Friday June 12 2015, @08:41AM (#195315)

      I'm not completely convinced about that. Photons do have a life span, they are generated and absorbed, and travel at a finite speed.

      • (Score: 0) by Anonymous Coward on Friday June 12 2015, @09:20AM

        by Anonymous Coward on Friday June 12 2015, @09:20AM (#195332)

        A finite speed that just happens to slow time down to, maybe zero?

  • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @11:41AM

    by Anonymous Coward on Thursday June 11 2015, @11:41AM (#194917)

    So Roko's basilisk may be possible after all. Time to start taking my meds again...

    • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @01:07PM

      by Anonymous Coward on Thursday June 11 2015, @01:07PM (#194936)

      Time to stop badmouthing System D, you mean!

      • (Score: 2) by wonkey_monkey on Thursday June 11 2015, @03:17PM

        by wonkey_monkey (279) on Thursday June 11 2015, @03:17PM (#194988) Homepage

        Hey, that's my schtick!

        --
        systemd is Roko's Basilisk
        • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @04:04PM

          by Anonymous Coward on Thursday June 11 2015, @04:04PM (#195013)

          Hey, that's my schtick!

          But it's such GREAT stuff, hope you don't mind some imitation-as-flattery.

  • (Score: 2) by khakipuce on Thursday June 11 2015, @12:08PM

    by khakipuce (233) on Thursday June 11 2015, @12:08PM (#194921)

    Is it not possible that forces around the second grate have a tiny (immeasurable) but real effect on helium atom and that this is nothing to do with weird time effects. A bit like putting a magnet close to an electron beam say?

    • (Score: 3, Informative) by CoolHand on Thursday June 11 2015, @01:10PM

      by CoolHand (438) on Thursday June 11 2015, @01:10PM (#194938) Journal
      I thought this at first, but:

      The fascinating part was, the second grate's very existence in the path was random. And what's more, it hadn't happened yet.

      The were inserting the second gate randomly after the photon passed the first gate...

      --
      Anyone who is capable of getting themselves made President should on no account be allowed to do the job-Douglas Adams
  • (Score: 2) by theluggage on Thursday June 11 2015, @01:05PM

    by theluggage (1797) on Thursday June 11 2015, @01:05PM (#194935)

    In other words, it was as if the helium particle "knew" whether there would be a second grate at the time it passed through the first.

    So, just as an unobserved particle doesn't have a specific location in space, just a wavefunction determining a range of places where it might be when observed, an unobserved particle doesn't have a specific location in time either - just a wavefunction determining range of times where it might be... including times where it would be affected by something that isn't there yet...? is that it?

    My head hurts - but at least that means that macro-scale objects are as unlikely to jump about in time as they are to tunnel through solid objects.

    • (Score: 2, Interesting) by dusty monkey on Thursday June 11 2015, @02:37PM

      by dusty monkey (5492) on Thursday June 11 2015, @02:37PM (#194959)

      I was thinking that because of relativity, different observers can disagree on when something happened. I postulate an unknown observer that disagrees.

      (using observer in the standard quantum science sense - a photon can be an observer, for instance)

      --
      - when you vote for the lesser of two evils, you are still voting for evil - stop supporting evil -
  • (Score: 2) by inertnet on Thursday June 11 2015, @01:12PM

    by inertnet (4071) on Thursday June 11 2015, @01:12PM (#194939) Journal

    “It proves that measurement is everything. At the quantum level, reality does not exist if you are not looking at it,”

    I could have believed him if he had said: "reality does not exist until there's interaction."

    His comment sounds as if anything we see is there just because we look at it. That's not how it works, particles exist because other particles interact with them. Measurement is interaction. That's weird enough for me.

    • (Score: 2) by Immerman on Thursday June 11 2015, @01:20PM

      by Immerman (3985) on Thursday June 11 2015, @01:20PM (#194941)

      That is one possible interpretation of quantum mechanics. But since it's pretty much impossible to meaningfully measure anything without a conscious mind reading the measurements, it's equally impossible to determine whether the superposition of states collapsed at the moment of measurement/interaction, or at the moment a conscious mind read those measurements.

      • (Score: 1) by dusty monkey on Thursday June 11 2015, @02:40PM

        by dusty monkey (5492) on Thursday June 11 2015, @02:40PM (#194960)

        t's equally impossible to determine whether the superposition of states collapsed at the moment of measurement/interaction, or at the moment a conscious mind read those measurements.

        We have a principal for this. The simplest explanations...

        --
        - when you vote for the lesser of two evils, you are still voting for evil - stop supporting evil -
        • (Score: 2) by sjames on Friday June 12 2015, @01:36AM

          by sjames (2882) on Friday June 12 2015, @01:36AM (#195224) Journal

          It's about the same though. Alas, we have no apparent way to decide which is the case.

        • (Score: 2) by Immerman on Friday June 12 2015, @03:21PM

          by Immerman (3985) on Friday June 12 2015, @03:21PM (#195424)

          ... are almost certainly wrong, but potentially incredibly useful if they're close enough approximations for the application at hand?

          Newtonian gravity
          electrons orbit the nucleus
          light is a wave
          atoms are particles (indivisible or otherwise)
          ...

          I could keep this up all day.

      • (Score: 4, Interesting) by Zinho on Thursday June 11 2015, @02:50PM

        by Zinho (759) on Thursday June 11 2015, @02:50PM (#194965)

        . . . since it's pretty much impossible to meaningfully measure anything without a conscious mind reading the measurements, it's equally impossible to determine whether the superposition of states collapsed at the moment of measurement/interaction, or at the moment a conscious mind read those measurements.

        Let's see if I can FTFY:

        . . . since it's pretty much impossible to meaningfully measure anything without a conscious mind reading the measurements, it's equally impossible to determine whether a tree falling in the forest made the sound when it fell, or at the moment you listened to the audio recording of the event.

        I'm probably going to sound like a QM noobie saying this, but the notion that consciousness is required for an interaction to take place seems ridiculous to me. By that logic, a star falling into a black hole millions of light-years away won't actually collapse its various quantum superpositions until we see it as we look through our telescopes. I think that was that actual point of Schrodinger's cat-in-a-box thought experiment; whether you've looked in the box or not, at the macro level the particle has either decayed and tripped the poison capsule (killing the cat) or it hasn't (and the cat is still alive). It is not necessary for the experimenter to know that the cat is dead or alive as long as the decay detector is working properly. The unconscious measurement instrument is sufficient to count as "observation", the human mind has no special place in the quantum universe.

        Of course, I'm just saying that because I'm a Niels Bohr fan :P

        --
        "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
        • (Score: 2, Insightful) by Delwin on Thursday June 11 2015, @03:32PM

          by Delwin (4554) on Thursday June 11 2015, @03:32PM (#194995)

          The only way I've been able to make sense of this is if we really are in a simulation. Then it makes perfect sense from a CompSci point of view - why calculate something until you absolutely need to?

          • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @04:25PM

            by Anonymous Coward on Thursday June 11 2015, @04:25PM (#195019)
            Yeah you only calculate what the consciousnesses would observe - save on CPU ;). Just like raytracing only what the "cameras" would see.

            Problem is if some scientists are right and consciousness is a fundamental and "everything is conscious" (because they have problems with consciousness[1]).

            [1] Consciousness is the 2nd most remarkable thing about this universe. The first being that the universe existing in the first place. It's a bit funny that scientists still have difficulty explaining the very first observation they make (assuming that they all experience consciousness - some might not given their responses/arguments on this topic).
            • (Score: 2) by mhajicek on Thursday June 11 2015, @10:50PM

              by mhajicek (51) on Thursday June 11 2015, @10:50PM (#195178)

              But you're the only truly conscious entity. The rest of us are like NPCs; we're only a simulation of a conscious entity.

              --
              The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
          • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @06:24PM

            by Anonymous Coward on Thursday June 11 2015, @06:24PM (#195081)

            As entertaining a thought that is, saying the universe is simulated instead of admitting that consciousness does not hold a sacred place in the cosmos is stretching very far.

            • (Score: 1) by HOLOGRAPHICpizza on Thursday June 11 2015, @08:37PM

              by HOLOGRAPHICpizza (5176) on Thursday June 11 2015, @08:37PM (#195137)

              I argue that it is more likely that we are in a simulation than not. Because we could theoretically one day build a computer big enough to hold the data and perform all the physics calculations for a universe. It would probably run much slower than real time, but you could just set up the initial conditions and let a big bang occur and watch solar systems form and life evolve and and all that, just by simulating particles and interactions.

              So if one civilization was able to create this, so will the civilizations that evolve within the simulation. I think it's extremely likely that we are in a simulation within a simulation within a simulation countless levels deep. Why should we be so arrogant as to assume we are the "top level universe"?

              • (Score: 0) by Anonymous Coward on Friday June 12 2015, @03:12AM

                by Anonymous Coward on Friday June 12 2015, @03:12AM (#195255)

                That logic is quite loose isn't it? It is just as likely that our entire universe is a spontaneous superposition within a dust mote of another larger universe within another larger universe and so on. Given that there are easily many trillions of trillions of dust motes in each one, it is even more likely for a Horton Hears a Who scenario to play out than a nested simulation.

                This would work with any other scenario that could both theoretically happen and if it did happen would theoretically happen many times.

                Our universe could be just a dream.
                There really could be a god of sorts within another god's work such that the universe is a shitty uni group project. [smbc-comics.com]
                Existence could be an illusion and the idea of a universe having meaning all together does not make sense.

                And things get even weirder if you let Cartesian doubt do what it does.

                I argue that of the infinite probable possibilities that we have without the data or means to start crossing them off any one possibility, like being in a simulation, is infinitely unlikely compared to any one of the others being true.

        • (Score: 2) by Immerman on Friday June 12 2015, @03:13PM

          by Immerman (3985) on Friday June 12 2015, @03:13PM (#195420)

          The difference of course being that everything we know indicates that the tree will make a sound whether or not anyone is observing it. Whereas with QM everything we know says that the superposition of states doesn't collapse until... some as-yet poorly defined point in time potentially much later. And it may never collapse at all (such as in the many worlds and other interpretations), with the apparent collapse only being an observer-imposed illusion resulting from the superposition encompassing the observers themselves. In which case it is very much the observer's mind causing the *apparent* collapse, by virtue of being able to perceive only a single state.

          Also, who said anything about humans being special? A mouse is conscious. An insect probably is (the more sophisticated ones almost certainly are), there's even a measure of evidence suggesting that plants may be.

          • (Score: 2) by Zinho on Friday June 12 2015, @05:21PM

            by Zinho (759) on Friday June 12 2015, @05:21PM (#195459)

            I appreciate your point regarding the macro/micro scale difference; I could have picked a better analogy.

            My point in making it was that the atom's interaction with the detector is sufficient in itself to cause the waveform collapse; whether there is a human/mouse/insect experimenter recording the output is irrelevant. "Conscious observer" in this context is irrelevant; either the diffraction pattern is created by the second grating, or it's not. Such interactions happen countless times in nature without our observation, and have no need of our awareness of them to occur. Was the projection screen that Young used for his original experiment conscious? Did the diffraction pattern exist when Young wasn't looking at it? The answers to these questions should be "it doesn't matter" and "yes". Saying that we need a "human" or "conscious" observer for the waveform to collapse is as ridiculous as saying that the tree falling in the forest didn't made a noise until we listen to the recording afterward.

            The real argument to have regarding this experiment is whether the second grating or the projection screen is the point at which "observation" occurred. I've been looking for more clarification on that's going on here, and found that in previous experiments with photons the second grating was added after the photon had passed it and still created the diffraction effect. [physicsworld.com] (check out the "Photon First" paragraph). That would have been a much more dramatic effect to replicate with an atom, and may actually require info going back in time.

            --
            "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
            • (Score: 2) by Immerman on Friday June 12 2015, @06:40PM

              by Immerman (3985) on Friday June 12 2015, @06:40PM (#195482)

              >the atom's interaction with the detector is sufficient in itself to cause the waveform collapse

              That is a perfectly reasonable assumption, but I can't think of any way to create a falsifiable hypothesis to test it. Can you? If the entire apparatus remained in a superposition until consciously observed, the outcome would be indistinguishable from an immediate collapse, would it not?

              Also "macroscopic" is an arbitrary a line to draw for quantum effects as "conscious". Massive neutron stars, are postulated to be heavily influenced by quantum effects, and the behavior of even more degenerate theoretical quark stars should be heavily dominated by quantum effects on scales that would make a laughingstock of our concept of macroscopic.

              I do agree that the timing of the second grating would be a more interesting question, but as mentioned in your link there is more than one interpretation

              this would force us either to conclude that our decision to measure the particle's path affects its past decision about which path to take, or to abandon the classical concept that a particle's position is defined independent of our measurement

              • (Score: 2) by Zinho on Friday June 12 2015, @10:17PM

                by Zinho (759) on Friday June 12 2015, @10:17PM (#195547)

                the atom's interaction with the detector is sufficient in itself to cause the waveform collapse

                That is a perfectly reasonable assumption, but I can't think of any way to create a falsifiable hypothesis to test it. Can you? If the entire apparatus remained in a superposition until consciously observed, the outcome would be indistinguishable from an immediate collapse, would it not?

                Fair point. Your question flirts with solipsism, which I also reject as highly improbable and unnecessarily complicated as a hypothesis. In this case I don't see either hypothesis as useful, since the experimenter isn't putting his own eyeball in the line of fire of the lasers or helium particles; instead, there's a screen being illuminated or a counter being incremented, and the researcher reads those. I'm fine with discussions about at what point in the apparatus up to and including the detector the waveform has collapsed, but I learned when I was 2 years old that things still exist when I don't look at them. [wikipedia.org] My failure to observe the output display of a Geiger counter should not change its count, provided that I'm not somehow interacting with its inputs.

                Also "macroscopic" is an arbitrary a line to draw for quantum effects as "conscious". Massive neutron stars, are postulated to be heavily influenced by quantum effects, and the behavior of even more degenerate theoretical quark stars should be heavily dominated by quantum effects on scales that would make a laughingstock of our concept of macroscopic.

                I think we're getting into the realm of "things I never said", but I'll go with you on this. I don't know whether quarks, atoms, rocks, trees, planets, or neutron stars are "conscious" or not. They've never spoken to me, so there's that, but what does it even mean to be conscious? Could we, in theory, test whether an object can cause a quantum waveform to collapse through "observation" as a guideline? If so, then there are some laser beams in quantum computing labs that count as conscious. Since philosophers can't even come up with a definition for consciousness that includes all humans (see solipsism again) I find it to be a useless metric in quantum physics.

                this would force us either to conclude that our decision to measure the particle's path affects its past decision about which path to take, or to abandon the classical concept that a particle's position is defined independent of our measurement

                This is where I've gone in my analysis of quantum physics. I give up on imagining atoms and their subatomic components as billiard balls or bullets, and accept that from emitter to detector they are unlike anything I see on a daily basis. I accept that, when they start moving, knowing their momentum prevents me from saying anything meaningful about their position; and that they may not even have a "position" the way I think about for things sitting on my desk. I'm more OK with this than the idea that they are somehow gaining clairvoyance and the mystic ability to determine whether something looking at them is "alive".

                --
                "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
                • (Score: 2) by Immerman on Saturday June 13 2015, @07:26PM

                  by Immerman (3985) on Saturday June 13 2015, @07:26PM (#195866)

                  I fail to see how the idea that waveform collapse occurs on observation is "flirting with" the idea that the self is the only thing that can be known to exist. I know perfectly well that their is a quantum waveform at with a given probability distribution in my box, I'm simply arguing that it might not collapse into a single concrete state until someone looks at the counter, rather than immediately upon interacting with the larger but still fundamentally quantum system of the detector .

                  Ah and, I seem to have dropped a word and changed the meaning of a paragraph. That should be

                  "Also "macroscopic" is as an arbitrary a line to draw for quantum effects as "conscious".

                  I didn't mean to suggest that stars are conscious*, but rather that any sort of "measurement" that relies on interacting with a macroscopic (and hence presumably non-quantum) system is challenged by the concept that entire classes of stars should exist in a state that can only be adequately described by their quantum wavefunctions. If an entire star can only exist as a non-classical quantum system, what makes you thing a Geiger counter is fundamentally different?

                  * The consciousness of stars would be a completely different discussion. I do happen to currently subscribe to the school of thought that consciousness is a fundamental quality of the universe rather than an emergent phenomena, but that's generally irrelevant to most discussions, probably even this one unless we can postulate a manner in which a star with a coherent consciousness could meaningfully observe our instrumentation.

                  • (Score: 2) by Zinho on Monday June 15 2015, @02:42AM

                    by Zinho (759) on Monday June 15 2015, @02:42AM (#196334)

                    The solipsism connection comes from the fact that "consciousness" is so poorly defined and understood that there are philosophers even today who claim to be unsure that anyone besides themselves even exists, let alone is capable of independent thought. If that's the case, how are we to determine what is and is not conscious? If we can't cleanly define consciousness, what kind of basis is that for a useful scientific theory?

                    "Macroscopic" can at least benefit from tautology - define it as the point at which quantum effects cease to dominate, and leave it at that. :P
                    Also useless as a guideline, especially given your very valid point regarding neutron stars.

                    For me, the essence of "observation" is interacting in a way that can determine the quantum state. In our labs that usually involves a destructive read - absorption and re-emission in the case of Young's screen, leaching some kinetic energy to create a cascade of freed electrons as in Geiger's counter, etc. Our detectors in the lab generally transduce the quantum state we want to read into a classical interaction that we can see, feel, hear, record electronically, etc. I would argue that the act of performing such a transduction is sufficient to count as "observation" in a meaningful sense and collapse the waveform, even if we figured out how to make it non-destructive.

                    The alternative you suggest is fraught with problems, not the least of which is deciding what counts as "observation" of the transducer. If I had a blind researcher listening for a Geiger counter's clicks, does the device fail to click if he leaves the lab to use the restroom? We are now exactly back to the question of "if a tree falls in the forest and no one is there to hear it, does it make a sound?" Pointing out that we don't have a meaningful way to test whether that is the case or not (because how can we know happens if the result looks the same either way?) is exactly the problem I have with solipsism - it posits an unnecessarily complicated world for no better reason than questioning "how can I know any different?"

                    I'll leave you a thought experiment which I hope would illustrate how we'd tell, extending the case of my blind researcher. Let's imagine that he's blind and deaf, and that the Geiger counter's output is a set of mechanical wheels (like a car's odometer) instead of a click, which the researcher reads by touch. If the system of quantum event -> detector -> counter were in a state of quantum superposition where for each possible nuclear decay even the wheels both turn and don't turn until the researcher reads the output then we enter a state of paradox. The wheels are not quantum devices; their state is overwhelmingly determined by the Brownian motion of the air around them and other classical interactions they experience, so how can their position be entangled with the uncertain quantum events being measured? They certainly aren't remaining stationary until just before being touched and then spinning rapidly to catch up; at some point that would require some portion of them to exceed the speed of light (depending on how long the researcher lets it run). The many-worlds hypothesis makes quick work of this paradox, creating parallel universes for each event detected; the researcher doesn't know which universe he's in until he reads the counter, but for each universe the counter wheels advance via classical mechanics based on whether or not an event was detected in that universe and are already in their appropriate state when the researcher touches the dial.

                    I'd love to keep this discussion going, I'm finding it invigorating. Unfortunately, I'm about to leave on a week-long trip in the mountains and won't be able to make any replies until next Saturday. Please follow up with another post, but be patient for my next reply ;^)

                    --
                    "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
                    • (Score: 2) by Immerman on Tuesday June 16 2015, @03:56PM

                      by Immerman (3985) on Tuesday June 16 2015, @03:56PM (#196901)

                      Well, if you want to bring philosophers into a scientific discussion you'll be there all night and probably never reach any conclusions - regardless of the topic. Modern philosophy has largely degenerated into mental gymnastics - it's great for developing strength and flexibility, but isn't actually directly useful for much. It just hasn't been the same since science and religion split off and took most of the practical questions with them.

                      Just because philosophers can't agree on whether anything beyond themselves doesn't mean there's no meaningful definition to be found - in fact it's a largely orthogonal question. Even if we had a perfect definition, we'd still run afoul of Descarte's evil-demon hypothesis and be unable to claim with certainty that anyone else even exists, much less is conscious.

                      You seem to see my point though -we could as easily define consciousnes by tautology: "a system which causes quantum wavefunctions to collapse when interacted with". In fact if we could find some way to detect exactly when the wavefunction collapsed, that might form the basis of a consciousness detector.

                      As for your cog-driving Geiger counter, of *course* the wheels are quantum devices - *everything* is a quantum device - what we call "classical physics" is the unexplained anomaly. How does combining a bunch of tiny quantum systems into ever-larger quantum systems eventually create something that appears to be governed by much simpler rules to a degree far beyond what can be explained by statistical averaging?

                      As for your speed question? If my preposition is correct then there would be no issue - the wheels would themselves would be in a superposition of states, having both rotated and not rotated as they interacted with the superposed measurement signal. The question is only whether the superposition collapses when it interacts with some poorly defined "macroscopic system", or if it continues to expand until it interacts with something conscious, or some other criteria is met, or even if it never actually collapses at all. There have been researchers who have managed to create mm-scale superpositions, so clearly it's not just "too many atoms involved", but as yet we really don't know what that criteria may be - it's *all* speculation. But clearly it doesn't simply end with the interaction of the initial superposed particle - far too many experiments have managed to transfer that superposition to other, often much larger, systems.

                      Enjoy the mountains, it's been too long since I spent a good chunk of time in them. I'll be around.

                      • (Score: 2) by Zinho on Monday June 29 2015, @08:28PM

                        by Zinho (759) on Monday June 29 2015, @08:28PM (#202987)

                        Thanks for the well thought-out answer! And your patience as well; I've been back for over a week now, but too busy catching up to spend time giving your response the consideration it deserves.

                        From what I read in your last post, I believe you and I are very close to each other philosophically, and perhaps talking past/around each other. I like your idea of a consciousness detector based on quantum waveform collapse; I even am open to the idea that we'll make startling discoveries, with many things we consider "inanimate" being detected as conscious. That would make for interesting news headlines, and perhaps a few amusing activist groups. [schlockmercenary.com]

                        That being said, I think I'm expressing myself poorly regarding my attitude towards consciousness. There are plenty of people willing to talk about consciousness who have more scientific street cred than philosophers; neuroscientists are a prime example. Even for them, though, it is a "hard problem". [livescience.com] Quantum mechanics is a difficult enough field to research, study, or understand; we do ourselves no favors be importing intractable problems from other fields. As a result, I find consciousness to not be useful as a tool in quantum mechanics.

                        Even if it were true, though, that conscious observation were the determining factor in waveform collapse, the mechanism by which that occurs would fall deeply into the field of untestable metaphysics. To restate one of my earlier ideas, how does the decaying atom know whether or not Schrodinger's cat is conscious? If the cat is asleep would it not be poisoned? If the cat doesn't count as conscious, how does the system know when/how/if/by whom it has been observed? If this is what's real, testing could/should be performed to determine its limits and explore it as a possible means of long-distance communication. If such testing is not possible, though, then it again isn't very useful as an analytical tool or avenue of research.

                        I mentioned Occam's razor in a different discussion thread, and I want to use (perhaps over-use?) it here. Instead of "observation" I prefer "measurement" as the collapsing action. Quantum entanglement is a delicate state, short-lived and easy to destroy. Certain types of interactions with an entangled system result in a determination of its state (e.g. measurement of polarization), which forces the waveform to subsequently act in a coherent manner for the entire entangled system (assuming that many particles are entangled). It is easy for me to believe that components of entangled systems behave consistently when measured because their entanglement requires it - if the measurements were going to be inconsistent, the particles wouldn't have been entangled in the first place. This is where the razor comes in - if I believe that the system is internally consistent from the beginning of the experiment, there is no need for me to be spooked out by measurements of widely separated entangled particles being consistent with one another.

                        Back to the article topic, my over-use of the razor in this case leads me to believe that the atoms of the experiment didn't need prescience or metaphysical awareness of the experimenter. If there are two grates and a detector, then the atoms will interact with grate A the same way every time that interaction takes place. If grate B is lowered, then the atoms interact with it; if it isn't, then they don't. At the detector, the atoms interact with the detector in a manner consistent with their history of previous interactions. This only causes problems if I want to believe things like that the atom has a specific position or path that it's following between grate A and the detector. That specific incorrect belief is what is disproved by this experiment. I am perfectly wiling to believe that grate B's interaction with the atom shifts it later behavior to be more wavelike than particle-like, and that there may not have been a specific path from grate A to detector in the first place.

                        Please understand that I'm not ruling out large-scale entangled systems. I'm actually quite looking forward to commercialized quantum computing systems, which rely on just such mass entanglements. I'm also looking forward to quantum cryptography, which may be needed to protect our privacy in a world with ubiquitous quantum computing; since good Q. crypto requires long-distance transmission of entangled pairs, I rather hope that entanglement over long distances (as has been repeatedly demonstrated) is not only possible, but practical and that we understand it well. I'm simply skeptical of interpretations of lab results which imply overly-complicated and untestable concepts of how the world works when much simpler explanations are readily available.

                        • (Score: 2) by Immerman on Tuesday June 30 2015, @03:00PM

                          by Immerman (3985) on Tuesday June 30 2015, @03:00PM (#203317)

                          If we are talking about "useful tools", then yes, I agree - for the time being at least discussions of interactions between consciousness and QM are unlikely to be terribly productive. That does not mean it's inherently untestable however, only that nobody has yet thought of the tests needed. If, however, someone *does* think of such a test (and a testable link is discovered) it's likely to have far-reaching implications for both QM and consciousness research. But that requires that someone with a suitably subtle intellect not dismiss the possibility out of hand. There may even be non-dimissive conversations with peers required.

                          I have no answers as to the mechanism and limits of such an interaction, at the moment I can't even think of any well-formed speculations. But then formulating and testing such hypotheses is the whole point of scientific research, is it not? Though I will admit I have my doubts that the addition of consciousness would have any impact on the potential for long-distance communications.

                          > Instead of "observation" I prefer "measurement" as the collapsing action.
                          And as a practical short-term matter, that is likely the most productive approach. I think it's important though to remember that that is a completely untested preference, a matter of faith, and should be treated as such in a scientific discussion, lest your confidence spread and discourage the explorations that might yield definitive results.

                          Occams Razor is a wonderful tool for formulating useful explanations, but I think it's important to consider that in a scientific context it has pretty much invariably led to false, or at least incomplete, theories. Arguably often among the best theories that could be reasonably expected to emerge from the constraints of the culture and technology of the time, but nevertheless theories that have since been proven fundamentally flawed.

                          • (Score: 2) by Zinho on Tuesday June 30 2015, @05:34PM

                            by Zinho (759) on Tuesday June 30 2015, @05:34PM (#203386)

                            I completely agree with everything you just said, I think we're talking the same language now.

                            There is plenty of room for speculation on what is and is not going on in QM, and plenty of areas where we're really not sure what's happening because our efforts to measure anything change the systems we're measuring. Research into those areas of our ignorance will require subtle minds open to new ideas and careful consideration of new possibilities.

                            As long as we know that's where our discussion is sitting, I have no problem with that. Given that I am an amateur in this field (I took the course in college, but that's not what I'm paid to do today) I tend not to have a lot of discussions at that depth. In most discussions of QM I try to restrict myself to things that I firmly understand (or at least, think that I do) and theory that is at least consistent with my textbooks if not widely accepted in the field.

                            As a result, I do tend to get a bit snippy in tone on occasion. As an example, when someone finds a way to test for quantum entanglement being passed to measurement instruments and/or requiring a conscious observer for the expanded entangled system to collapse there will literally be a pair of PHDs waiting for them at the end of the project, plus a mention in two different fields' textbooks. I'll be honest, I get a bit nervous about how people with a shaky grasp of the topic will interpret speculation along those lines when discussing things like that in public forums. Thanks, by the way, for pointing out how I was coming across; it gave me an opportunity to think through why I was reacting the way I did and consider better ways to express myself. Hopefully this paragraph is a more tone-neutral way of expressing the same sentiments.

                            Speaking of faith, I've actually found this conversation a bit surreal; I often find myself at the other end of it. I'm a man of faith, and believe that the universe we inhabit is a large-scale engineering project created to make a home for conscious beings like ourselves. I suspect, based on other components of my faith's philosophy, that it is possible that animals, the earth, and even sub-atomic particles may possibly have intelligence of a sort at a level we don't fully understand (as if we even understand our own intelligence or consciousness). Discussions of such things in scientific circles generally elicits immediate derision and out-of-hand dismissal on the basis that my beliefs are based wholly upon superstition and must therefore be false. In our conversation I feel like I've been playing devil's advocate, struggling to balance between respectfully (and, regretfully at times, silently) agreeing with your sentiments and trying to point out where they over-reach the current state of the art as I understand it.

                            Thanks again for taking the time and patience to have a well thought-out discussion. I'm not sure that I have much more to contribute to this one, so respond or not at your leisure. I'll be watching for your future posts, and look forward to more engaging conversations when the opportunities arise.

                            --
                            "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
      • (Score: 0) by Anonymous Coward on Tuesday June 23 2015, @01:03AM

        by Anonymous Coward on Tuesday June 23 2015, @01:03AM (#199672)

        I make it a point to sit down right next to certain people. No wonder the place is deserted, I could already sense the razor-sharp defensive spines, this heap of human preferred his personal space on the scale of rooms and had covertly scrutinized my actions from the moment I stepped in. Why was he even here? A dozen meters away from a never-ending stream of people?

        “Hello”

        No reaction, yet had it been possible the gap between us would have expanded at lightspeed. My neighbor would slam through the wall at the end of the bar counter, the wall he sat next to, and off into a dimension of his own.

        He looks in my general direction, nods hello, tries to classify me once again, ready to attack.

        Such attacks seldom happen to me, instead and after the customary period of silence what happens is this.

        “They're all wrong you know”

        “About what?”

        “Time travel”

        “Yeah?”

        “Grandfathers and paradoxes and killing Hister. It's all nonsense”

        “…”

        “You don't go backwards like that, you go backwards like forwards”

        “What do you mean?”

        “When you go backwards nothing at all happens to the you that travels from the future, nothing at all, nada, you don't travel at all or you can't tell you did. Everything happens to the you back then”

        I don't say it. If I say it I might as well not have bothered and left him alone without this peculiar kind of torture. Levity kills. He's not looking for sympathy or approval or any social trapping, and least of all scorn and ridicule.

        “Remember r, always remember r”

        He pauses and drinks a little in our bubble of calm. His defensive systems are back to passive mode. Is that all? Remember r? What is r? I try to make myself disappear in the hope of more.

        “You remember the future, that's what happens. You remember the future. You know something that is going to happen. Perhaps something you did but not yet. But you don't know why. You don't know how. You don't know when. You don't know where the memory of the future starts or stops or what is fantasy or how much your inner gecko is trying to help you out or if you've become insane or whether how much or if the future really is that bad or why it isn't impossible to die that many times in what seems such a short time and why the infantry charge is going up the side of the abyss in the deep-water trench or why you see them and their blazing guns and the supercavitational steam from front on. But it has the feeling of memory. Every time, for every slice of future”

        He looks me directly in the eyes for what seems like eternity compressed, then he looks at the people streaming past beyond me in the transit lounge. The debriefing is complete.

    • (Score: 3, Interesting) by mhajicek on Thursday June 11 2015, @10:47PM

      by mhajicek (51) on Thursday June 11 2015, @10:47PM (#195177)

      If reality doesn't exist until you're observing it, how could you wake up?

      --
      The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
  • (Score: 3, Insightful) by penguinoid on Thursday June 11 2015, @01:22PM

    by penguinoid (5331) on Thursday June 11 2015, @01:22PM (#194942)

    Putting the second grate farther from the source is meaningless -- it will merely change the interference pattern, but not produce any magic involving time-travel. In fact, the only way time-travel is involved in this experiment is if you believe the particle doesn't behave like a wave but merely chooses its path cleverly to pretend to be a wave. This experiment merely confirms that the particle will act like a wave even with blinky gates, but that isn't as newsworthy.

    --
    RIP Slashdot. Killed by greedy bastards.
    • (Score: 4, Informative) by draconx on Thursday June 11 2015, @02:54PM

      by draconx (4649) on Thursday June 11 2015, @02:54PM (#194967)

      The secondnexus.org article is rather sensationalist, with statements like "one thing is clear: This new wrinkle adds more questions than answers.".

      The phys.org article says the experimental results were predicted by quantum theory. So this serves to validate what we already know (which is important!). The news is that nobody had done this particular experiment before.

    • (Score: 1) by caffeinated bacon on Friday June 12 2015, @02:39PM

      by caffeinated bacon (4151) on Friday June 12 2015, @02:39PM (#195405)

      The particle will act like a wave even with blinky gates. Except when the blinky gate is off, and then it's a particle.
      How does it know if the blinky gate is on or off before it gets there?

  • (Score: 4, Interesting) by gman003 on Thursday June 11 2015, @02:29PM

    by gman003 (4155) on Thursday June 11 2015, @02:29PM (#194957)

    Almost all of the "absurd" results in quantum physics, like this one, come from most quantum physicists having no idea how their own field actually works. Partially because they don't accept the obvious correct interpretation, Many-Worlds, as being correct, but also because even the ones who do follow MWI don't fully understand how it works at an intuitive level.

    So let's look at this experiment from a MWI perspective:

    Experiment setup: 1 device to launch single helium atom on straight path. Two conditional junctions, A and B, where lasers may or may not alter the atom's trajectory, as determined by a QRNG. A is always present, B is sometimes added (also determined by QRNG) at some point after the atom leaves A. Two unconditional reflectors, c and d, that use lasers to alter the atom's path. Two particle detectors, 1 and 2. And finally, and observer. Setup is such that these are the only valid paths:
    B not present, A does not trigger: AcN2
    B not present, A triggers: AdN1
    No junctions trigger: AcB2
    Junction A triggers: AdB1
    Junction B triggers: AcB1
    Both junctions trigger: AdB2

    Atom of helium reaches first junction. QRNG randomly triggers a laser pulse at junction A.
    We now have two worlds, one where the helium is going to reflector c, and another where it's going to reflector d. I'll label them Ac and Ad for now. The observer remains unentangled at this point, so they see a superposition of Ac and Ad, which I'll call A*.

    A QRNG now determines whether to move junction B into place. If it does, we get two worlds AcB and AdB; if it does not, we get two more worlds AcN and AdN.

    The atom of helium continues on to the reflector, then reaches junction B. Here the four worlds split into six:
    AcN results in AcN2
    AdN results in AdN1
    AcB splits into AcB1 (if B triggers) and AcB2 (if it does not).
    AdB splits into AdB2 (if B triggers) and AdB1 (if it does not).

    However, from what I can see of their experimental setup, the quantum state of B "knows" which way the atom was coming from. So the superposition of states seen by the final particle detector is:
    A*N*
    AcB*
    AdB*

    Further, at least in photon-based versions of this experiment, path AdB2 and AcB2 both end at the same detector, but the photons end up 180 degrees out of phase. So detector 2 in an A*B* superposition sees A*B2 as always zero, as the two paths cancel each other out. That is what they consider "acting as a wave". However, when you have distinct configurations AcB* and AdB*, detector 2 does not see a superposition, but separate paths that do not cancel out, and it is "acting as a particle".

    Once the atom hits the detector, the observer becomes entangled with the system. So we get A*N*O, AcB*O, and AdB*O.

    Because the presence of the second junction is part of the system's quantum state, the observer does not see it acting as a wave when junction B is in position. The observer only sees wave action in A*N* worlds, and only sees particle action in AcB* and AdB* worlds.

    Note how no information traveled in any direction through time except forward. The mysterious effect was the observer learning which world they ended up in, not the particle being told which way it was going to go.

    Hopefully that made sense, I had to guess on some of their setup. But at least to me, this makes a hell of a lot more sense than "the future affects the past".

    • (Score: 1, Insightful) by Anonymous Coward on Thursday June 11 2015, @05:02PM

      by Anonymous Coward on Thursday June 11 2015, @05:02PM (#195036)

      Lol what a jackass.

      "the obvious correct interpretation, Many Worlds"
       
      Thanks for the laugh. I will leave you to go back to solving every other trivial matter for those of us with a brain smaller than Jupiter.

    • (Score: 4, Touché) by threedigits on Friday June 12 2015, @08:54AM

      by threedigits (607) on Friday June 12 2015, @08:54AM (#195325)

      The mysterious effect was the observer learning which world they ended up in

      This explains it very nicely for some of the observers, the ones that ended on the "right" worlds that we observed. Can you please explain how observers on the rest of worlds saw it? And more importantly, why we didn't end in one of those worlds?

  • (Score: 4, Insightful) by Zinho on Thursday June 11 2015, @03:03PM

    by Zinho (759) on Thursday June 11 2015, @03:03PM (#194975)

    Can someone explain to me why time travel has to be involved here? My simplified understanding of QM for this experiment goes like this:

    * the Helium atom is acting like a wave at all times, whether the grate is there or not
    * in the absence of the grate the waveform collapses at the detector in a way consistent with the behavior we associate with particles
    * In the presence of the grate the waveform collapses at the detector in a way consistent with the behavior we associate with waves

    I don't see how this experiment adds any new insight over the double-slit experiment with photons beyond "yep, it works with atoms, too!".

    --
    "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
    • (Score: 3, Funny) by aristarchus on Thursday June 11 2015, @05:32PM

      by aristarchus (2645) on Thursday June 11 2015, @05:32PM (#195052) Journal

      I don't see how this experiment adds any new insight over the double-slit experiment with photons beyond "yep, it works with atoms, too!".

      Yes, but did you miss the part about the helium atom choosing what to be? We are now facing a world, with sentient helium atoms! And they apparently know the future!

      • (Score: 2) by Zinho on Thursday June 11 2015, @05:43PM

        by Zinho (759) on Thursday June 11 2015, @05:43PM (#195059)

        Yeah, I saw that line; I wrote it off as toning down the message for the lay audience. I take it from your tone that you find it just as ridiculous as I do.

        For me, the whole "information transmitted back in time" idea for this experiment is a non-starter, and should have fallen to Occam's cutting room floor.

        --
        "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
        • (Score: 2) by sjames on Friday June 12 2015, @03:33AM

          by sjames (2882) on Friday June 12 2015, @03:33AM (#195259) Journal

          The wording may have been dumbed down, but the experiment DOES show quantum non-locality in time as well as space. Occam never sought to reject objective measurement in favor of simplicity.

    • (Score: 3, Informative) by sjames on Friday June 12 2015, @02:53AM

      by sjames (2882) on Friday June 12 2015, @02:53AM (#195249) Journal

      Since the second grate doesn't exist at the time it passed the first one, the only way the presence or absence of the 2nd grate can affect that collapse is if the quantum wave is non-local with respect to time as well as space. While that has been suspected, even expected to be true, this is the experiment that demonstrates it to be true.

      • (Score: 2) by Zinho on Friday June 12 2015, @03:54PM

        by Zinho (759) on Friday June 12 2015, @03:54PM (#195434)

        Since the second grate doesn't exist at the time it passed the first one, the only way the presence or absence of the 2nd grate can affect that collapse is if the quantum wave is non-local with respect to time as well as space.

        (emphasis added)

        False dichotomy detected. Actually, not even dichotomy; only one option is presented, and stated as exclusive to all other truths. Alternative explanation (not requiring time travel): the helium atom's behavior at the first grating is always invariant. Subsequent insertion (or not) of the second grating therefore doesn't change the physics at grating 1. It does, however, alter the behavior registered at the detectors because the second grating interacts with the helium atom's waveform if the grating is present, and doesn't if it is not.

        You have inspired me to read TFA, here's what I've found:

        The atoms did not travel from A to B. It was only when they were measured at the end of the journey that their wavelike or particle-like behavior was brought into existence,” Truscott said. If we are to believe that the atom really did take a particular path or paths, then one has to accept that a future measurement is affecting the atom’s past, he concluded.

        (emphasis added)

        Here's how I read that:
        A is not true.
        If A were true, it would require clairvoyance/time travel on the part of the helium atom

        OK, so I believe them that the atoms don't, strictly speaking, travel from point A to point B. I can then also reject the time travel nonsense. This paragraph reads a lot like what I originally wrote, plus some text guaranteed to confuse people who don't believe that matter can act as a wave.

         
        The abstract of the Nature article doesn't mention time travel at all. What it does say, is this:

        Our experiment confirms Bohr’s view that it does not make sense to ascribe the wave or particle behaviour to a massive particle before the measurement takes place.

        That fits with my understanding of wave-particle duality. Subatomic particles (and entire atoms, too, apparently) are odd things, and we can't think of them as bullets or ocean waves. Their reality is somewhere in between, and how they look to us depends largely on how we look at them.

         
        I'm not trying to be obtuse or confrontational here, I just want to know if there's something I'm missing. I didn't find it in the linked articles. Where else should I be looking? I'm happy to read up some more if that's what it takes for me to really understand this.

        --
        "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
        • (Score: 2) by sjames on Saturday June 13 2015, @12:14AM

          by sjames (2882) on Saturday June 13 2015, @12:14AM (#195570) Journal

          What time travel? (Yes, I know the dumbed down version used that phrase but they were confused) The non-locality in space doesn't mean the particle jumps from wherever it happens to be to the point where the wave collapses, it just means that it's position was indefinite and then becomes known. Why should time be privileged in that regard?

          So simply, the helium 'knows' the state grating 2 will be in because it is within that blurry region of space time that the particle 'calls' here and now.

          If that interpretation bothers you, you'll HATE theirs. They are saying that the atom doesn't actually do anything when released, but then once it's measured, it RETROACTIVELY fell through the two gates but it 'knew' (was affected by) the state of grate 2 because that state was known at the time it's motion retroactively happened.

          • (Score: 2) by Zinho on Saturday June 13 2015, @11:45PM

            by Zinho (759) on Saturday June 13 2015, @11:45PM (#195917)

            Yep, you're right, I hate that second explanation. Yours I like better. I'm OK with having a broader "now" and "here" for the particle, and the second grate interacting within the "here" and "now" of the particle.

            --
            "Space Exploration is not endless circles in low earth orbit." -Buzz Aldrin
  • (Score: 5, Interesting) by tonywestonuk on Thursday June 11 2015, @04:06PM

    by tonywestonuk (5117) on Thursday June 11 2015, @04:06PM (#195015)

    I often think that the universe is just lazy.... We might all be in one huge computer, with algorithms keeping track of every atom.

    Except, even for ultra intelligent aliens who built this beast of a computer simulating our universe, this would require some serious CPU. So to combat this, they introduced 2 things

    1) Speed of light constant, so that the ultra-computer has time to update things in different parts of memory concurrently as not even the most super of super computers can do things instantly.......and think of the synchronisation / deadlock problems this might cause?

    2) Lazy resolution of every particle in the universe, when it is actually needed to be resolved. Much easy to do a few equations at the point of observation, than for every clock cycle move / change state of every particle in the universe. If all the particles are Stateless, in fact they don't actually exist at all. (no hidden variables), and then just calculate from where the particle was emitted, to where it was observed, based on speed/direction. then no transfer of state between node of the supercomputer needed. Far easier this way.

    Yes, there will be crappy artefacts, as there is in every 3D game, but its about balancing these against the amount of CPU available to complete the simulation. And those virtual lifeforms arn't going to notice.........are they?

    • (Score: 2) by CoolHand on Thursday June 11 2015, @05:43PM

      by CoolHand (438) on Thursday June 11 2015, @05:43PM (#195060) Journal
      If I had mod points left, I'd give you a +1 interesting.. very HHGTTG of you.. :)
      --
      Anyone who is capable of getting themselves made President should on no account be allowed to do the job-Douglas Adams
    • (Score: 2) by cosurgi on Thursday June 11 2015, @09:44PM

      by cosurgi (272) on Thursday June 11 2015, @09:44PM (#195160) Journal

      I like this idea. There is some interesting tidbit:

      If some light source very far away emits a single photon (eg. a quasar, though it tends to emit a lot more than single photons), it emits it in all directions as a wave. Then if this photon is detected at Earth, suddenly it turns out that the photon wasn't emitted in all directions (think about the other side of the universe). But it was emitted towards Earth.

      That's what gave Wheeler & Feynman the idea for emitter absorber theory. And in this idea the act of detection (absorber) sends a wave backwards in time that exactly cancels out the initially sent wave.

      --
      #
      #\ @ ? [adom.de] Colonize Mars [kozicki.pl]
      #
      • (Score: 1) by tonywestonuk on Friday June 12 2015, @08:47AM

        by tonywestonuk (5117) on Friday June 12 2015, @08:47AM (#195317)

        " And in this idea the act of detection (absorber) sends a wave backwards in time that exactly cancels out the initially sent wave." -

        I'm not sure about this.... I think that if QM is trying to be mapped into a Newtonian universes, and you end up having to send waves backwards in time, then there is something wrong with the theory.. This is similar to Bells inequalities, where observation of a particle somehow sends information to its twin at the point of detection about what state it is in..... it cant do this. There has to be an alternative to what's going on.

            Pick one of the following:
            1) Particles have hidden state - NO, proven this isn't the case by Bells inequalities.
            2) Particles send information at superluminal speeds back in time to their entangled pair. - I just cant believe this.

        I worked with the person who first told me about this phenomena. As a computer programmer (and not a quantum physicist), I set out to try to prove him wrong, (and hopefully win nobel prize etc hahaha!).... so, In Java, I created a photon class, and a photon emitter. and a polarisation comparator, etc.... to model the whole thing as a program. And sure enough, the *ONLY* way I could get it to reproduce the results as seen in the real world, is by making the photon objects have shared state, so one would be able to communicate with the other.... So, I didn't get the Nobel prize after all, but I did prove to myself how very VERY strange QM is.

        BUT, there is 1 other way I could make it work...... and that is cheat! When the polarisation of either particle is detected, even though Math.random() is used to determine the polorisation, just generate loads of different instances of the simulation, and disclude instances where the physics didn't work. This way no information, or shared state needs to be transferred between them..... And I know, its cheating.....

          or is it?..... could this be what's really going on in reality?....as in, simply there is not a future outcome in many-worlds theory, that allows the particles to have different polarisations? I have say I believe this more than the sending of information instantaneously....

        • (Score: 3, Insightful) by cosurgi on Saturday June 13 2015, @08:24AM

          by cosurgi (272) on Saturday June 13 2015, @08:24AM (#195693) Journal

          Yep, I also implemented Bell's theorem to check this (in mathematica). And classically there's a way to break the Bell's inequality: you only need to have some failed measurements. IIRC about 19% failed measurements (do not have the result then discard this data) was enough. And funny thing: they have problems with detectors in laboratory to really go beyond this limit for detector efficiency, and simultaneously close other loopholes, e.g. space-like separation.

          --
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          #\ @ ? [adom.de] Colonize Mars [kozicki.pl]
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          • (Score: 1) by tonywestonuk on Monday June 15 2015, @11:10AM

            by tonywestonuk (5117) on Monday June 15 2015, @11:10AM (#196425)

            Wow - you went far further than I did!....this is very interesting.

            I'm guessing that 'Failed' measurements, is when you have 1 detector firing , without the other.... So the co-incidence circuit doesn't fire, and the result is discounted?. maybe those failed measurements, would have actually worked if the polariser was set to a different angle?

            I had assumed that for predicted correlations of exactly cos(2θ), this would require *lots* of errors for a classical explanation, as there would be failed measurements for every possible combination of angles of polariser, apart from the angles it would be set at......much greater than 19% (more like 90%, which increases towards 100% dependent on how strict the co-incidence circuit is)....

            IF it is only low, like 19%, then you might have a classical explanation on what's going on!..... or maybe you're just a very clever troll haha!

            • (Score: 2) by cosurgi on Monday June 15 2015, @05:51PM

              by cosurgi (272) on Monday June 15 2015, @05:51PM (#196598) Journal

              You got this a little wrong.

              "failed" is not when there's no coincidence. It is when you have coincidence, but the result is "rubbish". In theories there is no "rubbish" parameter. But when you do experiental work you get a lot of noise and other practical/technical problems that are best removed when you e.g. work in very low temperatures (liquid helium, anyone? - but that wouldn't help in this case btw). And experimentalists are doing the best they can to remove these problems. It's very difficult.

              But for Bell's inequality rubbish data fits very well: it is simply discarded, and thus it skews statistcs - you do not average over all measurement, but only some of them. And, funnily enough, it is enough to break the inequality classically.

              For example say that you are giving to Alice and Bob pieces of paper with written zeros and ones on them. And they write down in their notebooks what they received. They got columns with 1 & 0 there. And they are all written down from the pieces of paper that you gave them. That is a classical simulation of Bell's experiment (Currently I am actually thinking about CHSH Bell inequality, but it's the same thing). Usually in QM experiment they do careful measurements with their polarizes and write down 0 & 1. But in this simulation you just give them the pieces of paper. And in this classical simulation there is not way to break the Bell inequality, unless you are using a very clumsy postman to deliver those papers to Alice and Bob. Let's say that this postman drinks a lot of tea or beer and sometimes spills it on those pieces of paper. When Alice receives a paper with clearly written 1 on it and Bob receives a wet stained paper without either 0 or 1, they both got coincidence, but the result is rubbish. They then have to discard this measurement. IIRC 19% of failed measurements is enough to break Bell's inequality by classical means.

              --
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              #\ @ ? [adom.de] Colonize Mars [kozicki.pl]
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    • (Score: 0) by Anonymous Coward on Friday June 12 2015, @12:25AM

      by Anonymous Coward on Friday June 12 2015, @12:25AM (#195196)

      So, the universe is a giant haskel simulation? ... interesting...

      But damnit now I want to go program a ray-tracer in haskel... I'm not going to but ...

  • (Score: 2) by cosurgi on Thursday June 11 2015, @04:47PM

    by cosurgi (272) on Thursday June 11 2015, @04:47PM (#195030) Journal

    There's a full paper on http://libgen.in/ [libgen.in] and its numerous mirrors.

    --
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    #\ @ ? [adom.de] Colonize Mars [kozicki.pl]
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  • (Score: 0) by Anonymous Coward on Thursday June 11 2015, @05:30PM

    by Anonymous Coward on Thursday June 11 2015, @05:30PM (#195051)

    Simple, it's a bug in the matrix.

    • (Score: 0) by Anonymous Coward on Friday June 12 2015, @02:12AM

      by Anonymous Coward on Friday June 12 2015, @02:12AM (#195237)

      But if this were the Matrix, the Agents (or guardians) would not allow knowledge of the Matrix to be known or communicated.

      Maybe they would allow false knowledge to be transferred. Maybe they do not have absolute control of the circuits yet (similar to deep packet inspection), in which case anomalies will occur and some knowledge will escape to the subjects.

  • (Score: 2) by kaszz on Friday June 12 2015, @01:53AM

    by kaszz (4211) on Friday June 12 2015, @01:53AM (#195227) Journal

    If the whole setup is viewed as a wave nature. Then the parts of the setup will interact before anything becomes so specific you can measure anything. So what is seen is an edge of a wave that affect other parts before reaching enough momentum to be detected.

    There's no particles only waves that makes them up?

    (this experiment result will however upset the theories of the grates)

  • (Score: 2) by Reziac on Sunday June 14 2015, @01:25PM

    by Reziac (2489) on Sunday June 14 2015, @01:25PM (#196117) Homepage

    The correct conclusion is obvious: The experiment hasn't happened yet.

    --
    And there is no Alkibiades to come back and save us from ourselves.