Please create an account to participate in the Slashdot moderation system

 



Forgot your password?
typodupeerror
Science

Quantum Physics Parts Ways With Reality 568

Posted by kdawson
from the had-it-for-a-minute-there dept.
aeoneal sends us to PhysicsWeb for news guaranteed to induce headache in those wedded to the reality of, well, reality. Researchers from the University of Vienna have shown the violation of a stronger form of Bell's inequality known as Leggett's inequality. The result means that we must not only give up Einstein's hope of "no spooky action at a distance," we must also give up (some of) the idea that the world exists when we are not looking. From the article: "[Studies] have ruled out all hidden-variables theories based on joint assumptions of realism, meaning that reality exists when we are not observing it; and locality, meaning that separated events cannot influence one another instantaneously. But a violation of Bell's inequality does not tell specifically which assumption — realism, locality, or both — is discordant with quantum mechanics." From the Nature abstract: "Our result suggests that giving up the concept of locality is not sufficient to be consistent with quantum experiments, unless certain intuitive features of realism are abandoned." Only subscribers to Nature, alas, can know what features those are, as PhysicsWeb doesn't tell us.
This discussion has been archived. No new comments can be posted.

Quantum Physics Parts Ways With Reality

Comments Filter:
  • bye-bye! (Score:5, Funny)

    by FooAtWFU (699187) on Monday April 23, 2007 @09:30PM (#18849017) Homepage

    Nothing for you to see here. Please move along.
    See that? That's the gaping hole where Quantum Physics used to be. It's gone now, though, and all we have for comfort is bad science fiction.
    • Re:bye-bye! (Score:4, Insightful)

      by ShieldW0lf (601553) on Monday April 23, 2007 @09:51PM (#18849193) Journal
      Am I the only one that thinks to themselves, "One of these days, some really smart person is going to come out with a new and better theory of reality that reveals all this quantum mechanics stuff to be a bunch of quackery."?
      • Re:bye-bye! (Score:5, Informative)

        by Anonymous Coward on Monday April 23, 2007 @10:09PM (#18849375)

        Am I the only one that thinks to themselves, "One of these days, some really smart person is going to come out with a new and better theory of reality that reveals all this quantum mechanics stuff to be a bunch of quackery."?

        Nope, and a lot of physicists think that quantum mechanics is fundamentally broken beyond the level of fixing - though it is a massively useful theory from a calculational point of view, it has deeper problems than just the ones involved in this experiment, including the measurement problem [wikipedia.org].
         
        Nobody is really sure what quantum physics says about reality or locality. Each of the interpretations is flawed or incomplete in some way. You might be interested to read about David Bohm's interesting theory [amazon.com] - though a lot of people think it's garbage, it does illuminate the lengths you must go to to fashion a theory that is consistent with quantum mechanics yet doesn't completely shred your common sense notions of reality. I have no idea if the experiment in this article has anything to say about so-called "Bohmian mechanics," as the blurb was completely uninformative and I don't subscribe to Nature...
        • Re:bye-bye! (Score:5, Insightful)

          by kestasjk (933987) on Monday April 23, 2007 @10:52PM (#18849759) Homepage

          You might be interested to read about David Bohm's interesting theory [amazon.com] - though a lot of people think it's garbage, it does illuminate the lengths you must go to to fashion a theory that is consistent with quantum mechanics yet doesn't completely shred your common sense notions of reality.
          What does common sense have to do with anything? The way we experience the world wasn't set up to be able to understand it, but to survive in it.

          When we see an insect being tricked into thinking an orchid is a female insect we think "That orchid doesn't look anything like an insect, what a strange mistake to make", and a bat might use echo location and see us being aroused by something that simply has the texture and shape of a piece of paper which doesn't resemble the texture or shape of a female human and wonder how we could make such a mistake.
          Our common sense and intuition don't necessarily tell us what's true, especially when it doesn't relate the world we evolved in, so we have to rely on experiments, and quantum theory constantly makes accurate predictions. If it's beyond our common sense and intuition then that's too bad for us.
          • Re: (Score:3, Interesting)

            by Anonymous Coward
            Bohm's interpretation isn't the only alternative to the standard Copenhagen interpretaion. The "many worlds" interpretation is popular with science fiction (such as Stargate SG-1). There is also a "transactional interpretation" [washington.edu] by John Cramer. It invokes interactions between the future and the present, just as there are also ordinary interactions between the past and the present. And here [nemitz.net] is something that calls itself (only at the end of the file) an "aethereal interpretation". It starts by talking ab
        • Well, it makes sense (Score:5, Interesting)

          by Moraelin (679338) on Tuesday April 24, 2007 @06:21AM (#18852701) Journal
          Well, it all makes sense, if you think of it. Whoever is running this MMO we call RL, can't possibly have the resources to simulate every single particle all the time. So until someone actually goes and observes the damn thing, there's no need to actually spawn/instantiate it.

          Think of going farming for copper and tin ore in, say, the Gold Coast Quary in WoW. A particular ore spawn point might have been spawned as tin (most often), or as silver (rarely) or not at all. Would it already be spawned and in memory, if noone was there to see it? Or would it exist only as a probability until someone actually gets in range?

          Or say you're hacking away at a copper ore vein with your trusty cold iron pickaxe, like a good dwarf. Sometimes you get just a piece of copper ore, sometimes you also get 1-2 pieces of stone, sometimes you get a Shadowgem, or a Tigerseye or Malachite. Were they already there before you started to hack at the ore vein? Or did they exist only as a probability until someone actually gets that loot window?

          Of course, once you got a certain set of ore, stone and/or gems, closing the window and hacking at it again, won't change it. It stays the same set of, say, 1 ore, 2 stone, 1 gem until you actually loot them.

          I can tell you, the best gnomish engineers and mages have worked hard for an answer to those questions, but everyone came up empty. We just can't figure out a way to see what's there without seeing what's there. Even warlocks sending their Eye Of Killrog into the mine didn't manage to fool the system. That and the eye got killed by the bandits in the mine. The best priests whined... err... prayed piously to the great gods of Blizzard, and got no answer. Etc.
          • by MobyDisk (75490) on Tuesday April 24, 2007 @08:49AM (#18854273) Homepage
            Perhaps you are joking, but I've often wondered if quantum effects are caused by the universe having limited floating-point accuracy.

            Big things seem to move in simple and obvious Newtonian physics. But as we look smaller and smaller, things seem to jump from place to place, go through each other, and behave randomly. This is precisely what happens in a simulation as you approach 0 in floating-point. You can get seemingly random effects by adding very very small numbers together. It is also similar to what happens if an object in a video games moves very quickly relative to the the frame rate. The bullet may pass through things, especially other things moving quickly.

            Maybe, in a few generations, we will be able to break out of this universe, and see what is really out there.
            • Re: (Score:3, Interesting)

              by adavies42 (746183)
              AFAIK, one of the more important open questions is whether space and time are quantized the way mass/energy is.
              • Re: (Score:3, Funny)

                by Anonymous Coward
                God does not use float.
            • by Moraelin (679338)
              Well, yes and no. Mostly no. And I was indeed joking, and pretty heavy-handedly at that.

              Floating point errors tend to be more chaotic and unpredictable. QM is actually quite predictable and you can calculate useful stuff with it. E.g., it's not just that an electron in a potential well sometimes "tunnels through" (or rather, due to uncertainty principle constraints, it might have enough energy to jump or it might already be on the other side.) You can actually calculate how many will tunnel, and under which
            • Re: (Score:3, Informative)

              by stonecypher (118140)
              Perhaps you are joking, but I've often wondered if quantum effects are caused by the universe having limited floating-point accuracy.

              Max Planck and Claude Shannon beat you to it.
          • Re: (Score:3, Insightful)

            by Watson Ladd (955755)
            It depends if God uses Haskell or Lisp. (Yes, I know Lisp can be lazy)
        • Re:bye-bye! (Score:4, Insightful)

          by marcosdumay (620877) <marcosdumay@gma[ ]com ['il.' in gap]> on Tuesday April 24, 2007 @07:26AM (#18853197) Homepage Journal

          Well, people think quantum mechanics are flawed behond repair since before it come to be. Just remember that Plank after proposing that light is quantized spent most of he's career fighting that same idea.

          Quantum mechanics is not intuitive, but it pass every test we make with it. It's explaining things for the best part of a cetury now*, always proposing weard things, and aways getting it right. It's hard to replace a theory that works that well.

          * More than a century if you count since Plank, not Schrödinger.

          • Re: (Score:3, Interesting)

            by stonecypher (118140)
            Quantum mechanics is not intuitive, but it pass every test we make with it.

            This is only true if you discard things we haven't figured out yet. Then again, the same can be said for literally any theory, correct or not. There was a point at which we had the phlogiston pretty well figured out too. We had Newtonian Dynamics nailed down well enough to predict the motions of everything from pinball to the celestial spheres. There was a point at which we could predict how much energy a fire would pull out of
      • Re: (Score:3, Interesting)

        by glwtta (532858)
        Quantum mechanics is an actual scientific theory based on empirical evidence, it's the interpretation of it that quickly gets into the whole area of "philosophy, but with complex equations". And yes, a lot of it will turn out to be a bunch of hooey, but that's the nature of theoretical research. It would help if the people studying it didn't make grand pronouncements about the nature of existence every five minutes, but I guess that's why they wanted to be in that particular field to begin with.
        • Re:bye-bye! (Score:4, Interesting)

          by h2g2bob (948006) on Tuesday April 24, 2007 @12:07AM (#18850455) Homepage

          it's the interpretation of it that quickly gets into the whole area of "philosophy
          I agree with this. Physics is only about creating a model for how the universe works: you put numbers in, you get numbers out. What happens when we aren't looking (putting numbers in but not looking at the numbers coming out) has no real relevance and is unverifiable.
        • Re:bye-bye! (Score:5, Insightful)

          by kripkenstein (913150) on Tuesday April 24, 2007 @12:59AM (#18850793) Homepage

          Quantum mechanics is an actual scientific theory based on empirical evidence, it's the interpretation of it that quickly gets into the whole area of "philosophy, but with complex equations".
          You are 100% right that QM is a scientific theory. But, to say that only the 'interpretation' of QM brings us into the realm of philosophy is perhaps somewhat inaccurate. The distinction between a 'theory' and its 'interpretation' is not that clear.

          In particular, theories are judged based on what you might call 'philosophical' notions. And in fact, the great physicists - Newton, etc. - all had very deep philosophical ideas about their theories (although those are perhaps less well-known).

          As an example, we now consider Newton's law of gravity to be correct (up to relativistic considerations). Yet, at the time, many thought this to be philosophical nonsense. For what is gravity - it is 'action at a distance', with no mechanism! When a billiard ball hits another, the operation of force is clear, but why should some force exist between two billiard balls far apart? This is pretty much the same issue as the 'nonlocality' issue with QM. It took quite a lot of convincing to get the scientific world to agree with Newton's 'action at a distance', and the discussion was both practical (numbers, experiments) and 'philosophical' (how it fits into the rest of the current picture of 'reality' at the time).

          Anyhow, just trying to point out that science and philosophy are not disconnected. As science gets more specialized, it may seem so, since scientists don't get any philosophical training these days (they used to, though!).
          • Re:bye-bye! (Score:5, Interesting)

            by glwtta (532858) on Tuesday April 24, 2007 @03:25AM (#18851749) Homepage
            The distinction between a 'theory' and its 'interpretation' is not that clear.

            I was using "theory" in the sense that F = G (m1m2) / r^2 is the theory of gravity, and this [wikimedia.org] is a major part of the theory of QM. And, apparently, Newton didn't offer a philosophical "interpretation" for gravity*, while for QM we have "infinite number of worlds with consistently inconsistent histories entangling while moving backwards in time, located everywhere at once and communicating instantly", or whatever your favorite is :)

            I am not saying that that part isn't important - Newton's theory was superseded by one rooted in such a theoretical/philosophical concept ("curved spacetime"), after all. Just saying that these theoretical models only become useful when they start making testable predictions.

            * Came across this great quote from him in Wikipedia:

            I have not yet been able to discover the cause of these properties of gravity from phenomena and I feign no hypotheses... It is enough that gravity does really exist and acts according to the laws I have explained, and that it abundantly serves to account for all the motions of celestial bodies. That one body may act upon another at a distance through a vacuum without the mediation of anything else, by and through which their action and force may be conveyed from one another, is to me so great an absurdity that, I believe, no man who has in philosophic matters a competent faculty of thinking could ever fall into it.
            And general relativity takes a similar position, it describes how matter/energy curves spacetime, but makes no attempts to explain why that would happen.

            To put it another way - I agree with what you said.
        • Re: (Score:3, Insightful)

          by bitingduck (810730)
          I wish I had mod points for you...

          I've never understood why people get so hung up on having philosophical interpretations of it-- they aren't necessary or particularly useful.
    • by EmbeddedJanitor (597831) on Monday April 23, 2007 @10:17PM (#18849433)
      A site can still get slashdotted even if I don't look at it.
    • Re: (Score:3, Funny)

      by zekt (252634)
      All it's gonna take is for one of to look at Quantum Mechanics again and >poof it's 'reality' again :-p
    • Tachyeons (Score:3, Funny)

      by brunes69 (86786)
      Why don't they just throw some more Tacheyons at the problem?

      It always worked on Voyager.
  • yeah (Score:5, Funny)

    by gadzook33 (740455) on Monday April 23, 2007 @09:31PM (#18849023)
    sounds like some meetings i've been in
  • by Anonymous Coward on Monday April 23, 2007 @09:32PM (#18849031)
    closing my eyes at the age of four i knew the reality around me did not exist, so nobody could see me!
  • by Lurker2288 (995635) on Monday April 23, 2007 @09:34PM (#18849045)
    If you ask me, most of the people studying this sort of thing lost touch with reality long ago...
    • Re: (Score:3, Insightful)

      by Spazmania (174582)
      Entia non sunt multiplicanda praeter necessitatem. In my ever so humble opinion, Quantum Physics has long since exceeded the cut.
      • by Profane MuthaFucka (574406) * <busheatskok@gmail.com> on Monday April 23, 2007 @10:02PM (#18849295) Homepage Journal
        Latin, motherfucker!, do you speak it?

        • Re: (Score:3, Insightful)

          by idonthack (883680)
          Qvis?
        • Why yes, I do (Score:4, Insightful)

          by joeyspqr (629639) on Monday April 23, 2007 @11:50PM (#18850329)
          In fact, I have a degree in it.
          Hey kids. Get a degree in something you love, like Latin, or poetry, or whatever.
          Then go get a job doing your hobby, like computers (I'm not good enough to be a pro surfer). And keep practicing your love (yes, every kind of love).
          This will prevent quantum weirdness like waking up at 35 and realizing you hate your life.

          As far as the nature of reality ... that's as much as I know.
      • Re:A layman's view (Score:4, Insightful)

        by jfengel (409917) on Monday April 23, 2007 @10:52PM (#18849773) Homepage Journal
        Occam's Razor only lets you choose between two hypotheses which both adequately account for the data. Unless you've got some other theory with fewer entities in your back pocket that can explain things like the two-slit experiment and the Stern-Gerlach experiment, Quantum Mechanics is the only game in town.
        • by thrillseeker (518224) on Monday April 23, 2007 @11:07PM (#18849911)
          Occam's Razor only lets you choose between two hypotheses which both adequately account for the data.

          and the quantum version lets both be right.
        • Re: (Score:3, Insightful)

          by Spazmania (174582)
          Quantum Mechanics is the only game in town.

          Epicycles was the only game in town from the 3rd century all the way through the 16th... until Copernicus came along with the correct explanation for the data and made 1300 years of scholars look like raving lunatics.

          How then could Epicycle's proponents have known they were headed down a blind alley? Simple really: instead of proving it outright, each major new dataset required more refinements and additions to the theory -- Epicycles within Epicycles.

          Quantum Mecha
      • Re:A layman's view (Score:5, Insightful)

        by Coryoth (254751) on Monday April 23, 2007 @11:30PM (#18850151) Homepage Journal

        Entia non sunt multiplicanda praeter necessitatem.
        Occam's razor is all about pragmatism. It is not at all useful for determining truth, since the hoofbeats in the night might actually be some zebras that escaped from the zoo. What it does tell you is the safe side to place your bets, and, when it comes to models of reality, the pragmatists choice of the model that gets you your answers with the least fuss. Quantum mechanics has produced remarkably accurate results for a vast array of things -- indeed it has been tested to far greater accuracy than general relativity. It may well be that QM is just some complicated epicycle-like theory, but since we have no alternatives that can produce the same well tested answers it remains the safest bet, and the pragmatic choice for the model that gets those answers with the least fuss (since it is the only model that gets them at all).
  • First Post! (Score:5, Funny)

    by HeadlessNotAHorseman (823040) on Monday April 23, 2007 @09:35PM (#18849057) Homepage
    This comment is always the first post, as long as you are observing it. That's because by observing this comment you are not observing any previous comments, therefore they cease to exist!
  • by Theovon (109752) on Monday April 23, 2007 @09:35PM (#18849069)
    How are we in some way special that "observing" something makes it exist or converge to a single state or whatever? Are we not merely objects of matter that inhabit the universe just like everything else in it? Moreover, the universe existed before we were there to observe it. It seems to me that "observation" is a red herring. I prefer Penrose's hypothesis that it is gravity that causes superpositions to converge, which is why tiny objects can be in states of superposition, while macroscopic ones do not.
    • I think that "observing" in this context really means certain types of subatomic particle interactions. An atom is "observed" if a photon comes close enough to it for information about the state of the atom is transferred to the photon. (or something like that)
      • Re: (Score:3, Insightful)

        by Jasin Natael (14968)

        So, logically, the universe is powered by photons? Or reality as we perceive it is the interaction of particles, rather than the particles themselves? I'm not seeing much of a reason to panic and start worrying that the great turtle might awaken from his dream, but maybe it's just me.

        • Or reality as we perceive it is the interaction of particles, rather than the particles themselves?
          I like the sound of that. Kind of how in math the actual numbers aren't as important as the relationship between them.
        • by tibike77 (611880) <tibikegamez@yaho ... m minus language> on Tuesday April 24, 2007 @03:34AM (#18851817) Journal
          "Or reality as we perceive it is the interaction of particles, rather than the particles themselves?"

          Funny you should say that.
          Ever since I started studying physics/chemistry in high-school (at about the same time, 5th grade or so), I stopped thinking of "matter" as the defining issue, and started focusing on interactions between them almost exclusively.
          It makes no difference wether a particle/molecule/object actually "exists" or what "internal make-up" it has, the only thing you should ever care about is what types of interactions it can have with other particles/molecules/objects... nothing more, nothing less.

          Well, the "knowing about possible types of interaction" issue kind of makes it almost mandatory to understand exactly what any entity is actually "made of", but that's a secondary issue... if you know how something behaves in any possible situation, regardless of what's inside... do you really need to know what's inside ?
          Or, rather, if you know how something reacts to any imaginable interaction, would you have any actual means to determine without the shadow of a doubt "what's inside" ?
          My personal answers are both negative: you don't need to know, and there's no way to know for sure.

          Heh, here's the craziest thory: what if "space", "time" and "energy" don't actually exist (or worse, what if they're ALL discrete, not continuous) ?
          Would we even be able to notice ? Or have we noticed that already (Planck's h) but can't grasp the concept ?

          For all intents and purposes, the entire universe actually existing (on one hand) or being a completely fictional construct/simulation (on the other hand) makes no difference whatsoever.
          So, basically, all what's left of reality is simply interactions between entities, not any of the entities themselves.
    • by Ambitwistor (1041236) on Monday April 23, 2007 @09:50PM (#18849189)
      Humans don't have anything special to do with "observing" ("collapse of the wavefunction" or "state reduction"). A particle can be "observed" by a rock, or by any other "classical" macroscopic system with which it can entangle. Quantum decoherence in the consistent histories interpretation, IMHO, comes closest to explaining this process.
      • Re: (Score:3, Interesting)

        by NewToNix (668737)

        Humans don't have anything special to do with "observing" ("collapse of the wavefunction" or "state reduction"). A particle can be "observed" by a rock, or by any other "classical" macroscopic system with which it can entangle. Quantum decoherence in the consistent histories interpretation, IMHO, comes closest to explaining this process.

        There seems to be a flaw in that.

        It implies every thing is, in one way or another, being observed by something.

        That would mean that all things are observed at all time

    • Re: (Score:2, Insightful)

      by arse maker (1058608)
      In Physics, to observe something means to interact with a system in such a way that it changes whatever you use to interact with it. It has nothing to do with humans looking at it. When a photon hits your arm from the sun it analogous to an "observation".

      In regards to the article, I think more than a few already known quantum phenomenon make the idea of the universe not making a sound when no one is there to hear it, one of the less mind boggling ideas. Although its only mind boggling because we use our min
      • Re: (Score:3, Insightful)

        I still think Einstein's most accurate statement is that the most incomprehensible thing about the universe is that its comprehensible at all. There is no "reason" it should be or will continue to be.

        I view that as the primary form of a reverse-anthropic principle:

        The universe is comprehensible because the mechanisms of comprehension evolved within it by conferring an advantage to those organisms that have them. This only occurs for those aspects of comprehension which operate correctly within the universe
    • by kalirion (728907) on Tuesday April 24, 2007 @01:14AM (#18850929)
      It's really quite simple. Think of video games: the computer only renders the portion of the game that the player can observe (plus some nearby stuff for buffering, etc.). The Matr^H^H^H^HUniverse must act the same way to save on processing power.
  • Logic? (Score:3, Interesting)

    by geoffrobinson (109879) on Monday April 23, 2007 @09:36PM (#18849071) Homepage
    I found the following summary on the web from its conclusion:

    "We have experimentally excluded a class of important non-local hidden-variable theories. In an attempt to model quantum correlations of entangled states, the theories under consideration assume realism, a source emitting classical mixtures of polarized particles (for which Malus' law is valid) and arbitrary non-local dependencies via the measurement devices. Besides their natural assumptions, the main appealing feature of these theories is that they allow us both to model perfect correlations of entangled states and to explain all existing Bell-type experiments. We believe that the experimental exclusion of this particular class indicates that any non-local extension of quantum theory has to be highly counterintuitive. For example, the concept of ensembles of particles carrying definite polarization could fail. Furthermore, one could consider the breakdown of other assumptions that are implicit in our reasoning leading to the inequality. These include Aristotelian logic, counterfactual definiteness, absence of actions into the past or a world that is not completely deterministic. We believe that our results lend strong support to the view that any future extension of quantum theory that is in agreement with experiments must abandon certain features of realistic descriptions."

    _______________________

    I may be a simple man but a breakdown in Aristotelian logic? What are they going to use to argue against logic? I would assume logic.
  • Anything in their argument is fair game: Logic, the existence of sets of photons, and the absence of faster then light communication. I hope for the last one.
  • The Universe (Score:3, Interesting)

    by panxerox (575545) * on Monday April 23, 2007 @09:38PM (#18849079)
    was created when I was born and will end when I die.
  • Original paper... (Score:5, Informative)

    by aivuk (1092315) on Monday April 23, 2007 @09:48PM (#18849175)
    you can find here http://arxiv.org/abs/0704.2529 [arxiv.org].
  • meaning that reality exists when we are not observing it
    So I guess this means that a tree falling in a forest DOES make a sound even if nobody is there to hear it.
    • by Guppy06 (410832)
      If there's nobody there to hear the tree, the tree may not exist at all. If anything, the falling tree both makes a sound and is silent, until an observer is there to resolve it.
  • by the_other_one (178565) * on Monday April 23, 2007 @09:49PM (#18849181) Homepage

    we must also give up (some of) the idea that the world exists when we are not looking

    Does this mean that sticking your head in the sand actually works?

  • this is a test to see if unread comments on slashdot really exist

    if you are reading this, congratulations, you have participated in bringing this comment into reality
  • Theists have a ready answer to these problems. God's always watching, therefore there's always somebody observing, and thus maintaining reality. The clockmaker universe guys known as Deists have a bit of trouble though. Who is their observer?

    • by ewhac (5844)

      The clockmaker universe guys known as Deists have a bit of trouble though. Who is their observer?

      Deists don't claim that God doesn't watch over the Universe. They merely postulate that God doesn't interfere or meddle in its day-to-day operation.

      Schwab

      • by dbrutus (71639)
        But in this case, observation by definition is interference so the deists are still behind the 8 ball on this.
    • Theists have a ready answer to these problems. God's always watching, therefore there's always somebody observing, and thus maintaining reality.
      Yes, God keeps the universe in existence by going around from place to place saying, "Can you see me now?".
  • by creimer (824291) on Monday April 23, 2007 @09:56PM (#18849249) Homepage
    ... for news guaranteed to induce headache in those wedded to the reality of, well, reality.

    It's a no brainer that marrying a real woman would be more trouble than marrying a virtual woman.
  • by Ant P. (974313) on Monday April 23, 2007 @09:58PM (#18849263) Homepage
    The universe uses portal-based rendering. The only question now is, is it Direct3D or OpenGL?
  • Truly, a naive sense of reality is overrated. What we think of reality is solidly based in our personal experience. Second hand experience just isn't the same. For instance, if one has never seen a black swan, then the black swan does not exist, no matter how many times others tell you it does. Even if I see pictures of a spheroid earth, and watch the shuttle, or even my own project, orbit the spheroid earth, do I truly internalize that reality, or continue with my everyday experience of a flat earth?
  • by Henry V .009 (518000) on Monday April 23, 2007 @10:08PM (#18849363) Journal
    We've known for a couple decades that EPR made local hidden variable theories extremely unlikely. The real competitors are non-local. Bohmian mechanics (de-Broglie pilot wave theory, really) is one such. Bohmian mechanics make all the same experimental predictions as normal Quantum Mechanics. Bohmians tend to think of Quantum Mechanics as a non-local theory that only appears local because you talk about probabilities instead of positions. The probabilities of Bohmian mechanics are actually just as local as Quantum Mechanics...

    Not that Bohmian mechanics should be viewed as a correct theory. It's clearly an artificial construct. But it's a better theory than QM for the simple fact that it talks about particle positions instead of observers. One assumes, after all, that physics goes on even when physicists aren't there to observe it.
    • Re: (Score:3, Interesting)

      by radtea (464814)
      We've known for a couple decades that EPR made local hidden variable theories extremely unlikely.

      There is new science here. What they have shown is that any "reasonable" nonlocal theory cannot reproduce the results of experiment (which are correctly predicted by quantum mechanics.) This is building on the foundations that Bell laid, but is a significant new result.

      What they do is assume that the down-conversion source produces pairs of photons that have real polarizations. They then put some limits on th
  • If the theory of evolution is correct, and we did not always exist in our current form, which means we have not been around to observe the universe through most of its life, how does it exist? Perhpas it was created spontaneously? Spooky!!!!!!

    Quantum mechanics works at the level of the atom; I think it's safe to say that when I go to bed tonight, my house and all its furnishings are not suddenly going to cease to exist or even waver in their existence while I'm dreaming.

  • I gave up reality a while ago.
  • Student: I'm enlightened: reality is an illusion.

    Master: (hits student with a cane)
  • From what I have read, the inequality violations can not be used to communicate information faster than the speed of light. From a purely philosophical standpoint, without even getting into any math, reality by definition requires observers and for the most part people observe different things. When people exchange information, they have a more complete understanding of their collective experiences. It's nonsensical to speak of reality outside of that collective experience.
  • by Ungrounded Lightning (62228) on Monday April 23, 2007 @11:00PM (#18849851) Journal
    As I read it they're not saying anything about the universe not existing when nobody's looking.

    Quantum mechanics has a set of descriptions of matter/energy that "feel" incomplete.

    To "classical physics" thinking the collapse of wave functions of entangled particles seems to require either some faster-than-light communication between the entangled particles (to tell the far one about how the near one was observed - violation of "locality") or some hidden variable (to carry information slower-than-light from the point in space-time where they became entangled to the point where each is observed - "realism" would include this hidden variable as part of the particles' state). Quantum mechanics doesn't describe either. It just describes a situation where this sort of thing just happens - in a way that you can't use it to carry information faster than light from one spacetime location to another.

    Lots of work is being done to see if quantum mechanics can be "patched" into a more classical theory, in a way that preserves realism and locality by figuring out some way that a hidden variable can carry, from the entanglement to the observation at no more than lightspeed, the information necessary for a classical mechanism to produce the same result.

    This work shows that some simple experiments have already eliminated a very broad class of such hidden variable theories - to the point that "realism" patches involving hidden variables carrying additional information with the particles looks pretty hopeless. This is another step toward the "quantum mechanics really is all there is to it" viewpoint.

    (Of course I Am Not A Physicist so I could be reading it wrong.)
  • by StarkRG (888216) <starkrg@NoSpAm.gmail.com> on Tuesday April 24, 2007 @04:34AM (#18852109)
    I am the center of the universe.
  • MEASURE, not OBSERVE (Score:3, Informative)

    by DynaSoar (714234) * on Tuesday April 24, 2007 @03:33PM (#18860969) Journal
    There's a whole passel of improperly informed people yakking on about consciousness and its relation to reality and other ridiculous notions, specifically because people insist on confusing the necessary MEASUREMENT with the irrelevant OBSERVATION. Collapse of quantum wave functions requries interaction with another non-entangled wave function such as a measuring device. All of the results which support the inequalities tested and referenced here were produced using equipment which measured the phenomena and gave results well before any observation occurred. The parent, and the blurb in Nature both imply the mistaken idea by using terms that refer to a observer. Nature should know better. Everybody else that's really interested in understanding it should learn better. It makes the science much more interesting. But then it weeds out the semi-informed speculativists and the newage (rhymes with sewage) pseudoscientific-spiritual theorists. Being the vast majority, they obviously tend to revolt at the insistence on being correct.

Never try to teach a pig to sing. It wastes your time and annoys the pig. -- Lazarus Long, "Time Enough for Love"

Working...