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Science

Entanglement Could Be a Deterministic Phenomenon 259

Posted by kdawson
from the playing-dice dept.
KentuckyFC writes "Nobel prize-winning physicist Gerard 't Hooft has joined the likes of computer scientists Stephen Wolfram and Ed Fredkin in claiming that the universe can be accurately modeled by cellular automata. The novel aspect of 't Hooft's model is that it allows quantum mechanics and, in particular, the spooky action at a distance known as entanglement to be deterministic. The idea that quantum mechanics is fundamentally deterministic is known as hidden variable theory but has been widely discounted by physicists because numerous experiments have shown its predictions to be wrong. But 't Hooft says his cellular automaton model is a new class of hidden variable theory that falls outside the remit of previous tests. However, he readily admits that the new model has serious shortcomings — it lacks some of the basic symmetries that our universe enjoys, such as rotational symmetry. However, 't Hooft adds that he is working on modifications that will make the model more realistic (abstract)."
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Entanglement Could Be a Deterministic Phenomenon

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  • I knew it. (Score:5, Funny)

    by Anonymous Coward on Friday August 28, 2009 @10:08AM (#29231189)

    Free will is a sham. Of course, believe whatever you will. It's not like you have a choice.

    • by brian0918 (638904)
      I choose NOT to make a choice!
      • Re:I knew it. (Score:4, Insightful)

        by idontgno (624372) on Friday August 28, 2009 @10:42AM (#29231707) Journal

        I choose NOT to make a choice!

        Rush [lyricsfreak.com] thanks you for making your choice.

        • by lgw (121541)

          Lyrics as written in the album pull-out: "if you choose not to decide you cannot have made a choice".
          Lyrics as sung: "if you choose not to decide you still have made a choice".

          So they're agnostic on what it means to be agnostic - I refuse to believe this was a printing mistake, it's just too clever.

          • Lyrics as written in the album pull-out: "if you choose not to decide you cannot have made a choice". Lyrics as sung: "if you choose not to decide you still have made a choice".

            This is covered in the Rush FAQ [nimitz.net] - evidently it was printed correctly in Canada, which is why whenever some American told them it was wrong, they replied "no it isn't, eh."

      • Re: (Score:3, Insightful)

        I choose NOT to make a choice!

        That seems foolish to me.

        - If you have free will and do your best to exercise it in your own interest, you have a chance to exert some control over your situation and benefit yourself.

        - If you have free will and do not do your best to exercise it in your own interest, you are likely to do poorly.

        - If you don't have free will it doesn't matter.

        So the best path seems to be to assume you have free will and act accordingly.

    • by Kagura (843695)
      Our brain does not work on quantum processes, anyway! I can't know this for sure, but come on... use your brain!
      • Everything "works on quantum processes".
        • Re: (Score:3, Interesting)

          by Toonol (1057698)
          That's obviously true. However, I think in the case of the brain, it's even more explicit. There are mechanisms in place that act to massively amplify signals, specifically geared to utilize quantum effects. It's going to be one of the difficulties in building an actual replica of the human brain in software; emulation at the level of the neuron is insufficient. There are quantum effects that need to be simulated within the inner structure of a single neuron.
    • Re:I knew it. (Score:5, Insightful)

      by Chris Burke (6130) on Friday August 28, 2009 @10:55AM (#29231879) Homepage

      Free will is a sham. Of course, believe whatever you will. It's not like you have a choice.

      Dude, if you were counting on the non-determinism of quantum entanglement to save the concept of free will, then you were out on a limb to begin with. How is randomly following the rules of the universe any more a matter of "will" than deterministically following them?

      You could try to rely on a seriously weird and unlikely interpretation of QM which is basically a pun (measurement -> observation -> observer -> sentient observer), but then you're using the concept of sentience/free will influencing quantum events to explain how sentience/free will is possible in the first place. Maybe it's possible, but it's quite a long shot to be basing your whole concept of self awareness on.

      I have free will because as far as I can tell I exercise it. In a pure philosophical sense you could never prove you have it even if we somehow did show that QM is influenced by "observers". But that act of faith has worked well enough for me. I'm certainly going to live my life as though I have free will, and if I'm only "automatically" making that choice, then so be it.

      • by Brain-Fu (1274756) on Friday August 28, 2009 @11:25AM (#29232263) Homepage Journal

        When you model the universe in terms of will-less mechanisms, you will (amazing!) discover that free will is a logical impossibility.

        Trying to model free will in terms of physics is like trying to describe the combustion engine using only the words found in a book on home gardening.

        The only reason some people find this personally problematic is because they have decided that our current model of physics is also the concrete, accurately-represented holy truth. In fact, our current model is just an abstract representation of something we can't see, and it is just the best we've come up with so far (in fact, any scientist worth his salt will predict that our models will change in the future).

        So the quantum-mechanical model of the universe is incompatible with any free-will-is-real model of the universe. So what? This incompatibility doesn't make either theory right or wrong. The evidence for each theory is all that matters.

        As Epicurus [wikipedia.org] (one of the fathers of the modern scientific method) advised, "if several theories are consistent with the observed data, retain them all."

        • by Korin43 (881732)

          And how would you model the universe.. In terms of magic?

          • Ask an alchemist. (Score:4, Insightful)

            by Anonymous Coward on Friday August 28, 2009 @12:23PM (#29233089)

            Or maybe a Sorceror.
            Or maybe a Christian.

            Modeling the universe in terms of magic is what humanity has been doing for most of recorded history.

            Modeling the universe in terms of mechanical interactions of particles or waves is the new-and-cool. And we are still getting our heads around how to do it.

          • by Torodung (31985)

            Why not? Belief systems still function even though we don't understand why or how they work. For most of the population, quantum physics might as well be magic!

            I have a particular opinion about which is a better model, but I'm an admittedly lousy "magical thinker." ;^)

            --
            Toro

          • Any model will do (Score:2, Insightful)

            by HarryatRock (1494393)
            It doesn't matter what you base a model on, the value of a model is purely a matter of how good it works as a predictive tool (or as an aesthetic object for the artistic). If I model the moon as cheese and it gives the right answer for seismic readings, then it's a good model. If you are looking for absolute truth in a model, then I am afraid you are living in the wrong universe.
          • by lgw (121541)

            And how would you model the universe.. In terms of magic?

            That question seems to miss the point. The word "truth" means something different in science. Science seeks to answer the question "what is a useful and predictive model of how the universe works", and often calls that concept "truth". Science is just not involved with the question of "OK, that's a model, but how do things really work?". Scientists are of course as interested in that philosophical question as anyone else, but "how do things really work?" is a question of philosophy, not science.

            If the b

          • Re: (Score:3, Interesting)

            by mindbrane (1548037)

            Threshold is a good working concept when addressing how to model a complex thing. In science threshold can be ostensibly seen in terms of the first microscope and the first telescope. From there spectroscopy presents another method with certain thresholds. Studying sound to model the inner sun is a recent example to getting around limitations to extend our present thresholds enabling and constraining our ability to model the Universe. The fact that we've hypotheses like String Theory suggests there are thre

          • I'd start by making a universe doll and then I'd start sticking pins into it to see if it screams.
        • Re: (Score:2, Interesting)

          by Anonymous Coward

          The current model of the universe is not necessarily composed of will-less mechanisms.

          In fact the non-determinism of QM (if it is so) could be exactly the mechanism by which free will is introduced into the universe. QM does not have to be random as insinuated by the GP, but it instead could be the method by which free will forces (perhaps our 'souls') outside the universe (as we see it) inject their free will into the universe (by slight manipulation of the odds so to speak).

          I don't believe this myself, b

          • Re: (Score:3, Interesting)

            That's really insightful, and I'd give you a +1 for it. You're completely right that the introduction of our will could very well be us, without knowing due to barriers beyond science, changing a quantum particle from a superposition into one of it's potential positions. In fact, there's no proof that the essence of a person's mind actually is created on this plane of existence, lending a large amount of potential to this argument.
        • Re: (Score:3, Insightful)

          by internic (453511)

          When you model the universe in terms of will-less mechanisms, you will (amazing!) discover that free will is a logical impossibility.

          So the quantum-mechanical model of the universe is incompatible with any free-will-is-real model of the universe. So what? This incompatibility doesn't make either theory right or wrong. The evidence for each theory is all that matters.

          I've never seen a definition of "free will" that would be empirically testable. Actually, I don't think I've ever seen a definition of fre

          • Re: (Score:3, Interesting)

            by lgw (121541)

            My own definition of free will, from the philosophical side, is the same as "conscious choice". Free will reduces to the question of sentience or self-awareness (or actually a precondition for that), which is not itself well-defined but is still interesting. Basically, if you think you have free will, you can't be wrong, any more than if you think you're in pain you can be wrong. It's empirical, but only as a concious state, just like pain.

            • by internic (453511)

              I can accept that sort of definition as somewhat reasonably, but that seems to remove it entirely from the realm of metaphysical arguments people like to have about free will.

        • by ceoyoyo (59147)

          No, you don't. Newton's clockwork universe is certainly composed of "will-less mechanisms" yet once you investigate closely you notice that there are nooks and crannies where unpredictability hides, allowing for things like free will. Likewise, the standard interpretation of quantum mechanics doesn't have any "and here there be willful bits" in it, yet quantum uncertainty and randomness leaves the door open for free will. Most hidden variable QM interpretations, likely including this one, also leave room

        • by Chris Burke (6130)

          The thing is, I don't see it just as a matter of existing models being incompatible free will. I don't see how any model of the universe, whether deterministic or probabilistic, supports the idea of free will.

          So I can certainly see your point that the current model may be wrong, and that we may simply not be using the right language to describe the universe, but my question is, how do you introduce that language to expand the models that can be expressed to include those that allow free will? And don't ju

      • I have free will because as far as I can tell I exercise it.

        Free from what? That's the real question.

      • Interesting subject.

        You could try to rely on a seriously weird and unlikely interpretation of QM which is basically a pun (measurement -> observation -> observer -> sentient observer), but then you're using the concept of sentience/free will influencing quantum events to explain how sentience/free will is possible in the first place.

        Or maybe just pointing out that there's room for free will in the quantum model. I know the idea is unpopular among physicists, but I didn't think anything had emer

        • by siride (974284)
          I feel like you are so close...nobody here bothers to define what free will actually is or means. But they *know* it is incompatible with determinism. That's no way to run a debate or scientific inquiry.
        • by Chris Burke (6130)

          Or maybe just pointing out that there's room for free will in the quantum model. I know the idea is unpopular among physicists, but I didn't think anything had emerged that made it significantly less likely than any other interpretation.

          I don't like the idea of taking some poorly understood part of the universe, speculating that "consciousness" might be involved because it isn't explicitly excluded by current understanding, and saying that's where free will lies. It sounds like wishful thinking to me, or a

      • by Atario (673917)

        I have free will because as far as I can tell I exercise it.

        Or, put another way, you are not capable of perceiving the phenomena that constitute your deterministic behavior ahead of time. This should come as no surprise, since doing so would no doubt interact with that very behavior. Not to mention that we're all caught up in a Sensitive Dependence On Initial Conditions maelstrom on every level imaginable.

    • by kiick (102190)

      ...because I choose to believe that I have free will.

      If you don't believe in free will, then there's no use arguing with me, because it's been pre-determined that I will believe in free will.

      PS:
      Isn't trying to change someone's mind pretty much a futile gesture to a determinist?

      • by Rockoon (1252108)
        No.

        I am a determinist because I believe that everything that ever happened and everything that ever will happen can be explained by particles following one simple rule: The path of least resistance.

        The fact is that in following that path, my brain insists on convincing you of my wisdom. It may very well be that in following that path, your brain begins to believe that I am in fact extremely wise.

        That this is inevitable, I cannot say.
        • by Torodung (31985)

          And the path of least resistance is inevitably entropy. The abyss called, it wants to stare back at you.

          Scary to consider, but I think you're dead on.

          --
          Toro

    • Re: (Score:2, Funny)

      by sexconker (1179573)

      It may be, but science has not even attempted to define who I, my conscious self, am.

      How does a lump of grey matter result in a singular consciousness?

      All you other fuckers, you're just deterministic machines. I could model you perfectly given enough time.

      But me? I'm something...else.

    • by JamesP (688957)

      Well, will is nothing more than the output of a huge amount of data fed into a chaotic function.

    • by HiThere (15173)

      You could try the definition of "free will" that Larry Niven used in "Protector":

      Free will is the result of not being able to accurately predict the best action.

      That's a paraphrase, but I think I preserved all the meaning without dragging in a lot of story context. If you know what the best action is, then you will follow that course of action. So you don't have free will. If you don't know, and you don't know enough about yourself to accurately model why you are making the decision that you are making,

      • There are theoretical arguments that imply that it's impossible to accurately model why you are making your decisions at any great level of detail. They're rather convincing, but not totally so, especially when I slip in the constraint "at any great level of detail" rather than claiming perfection in the modeling.

        But they're still rather convincing. And then there's the time element. By the time you've finished your modeling, the decision is likely to be long past.

        So free will is a good working approxima

    • not necessarily. [philosophypages.com]
  • by Twillerror (536681) on Friday August 28, 2009 @10:09AM (#29231213) Homepage Journal

    I've often been skeptical of the idea that you could disproove a hidden variable. The hidden variable itself could be dynamic controlled by another hidden variable.

    I guess I just assume that there is more we don't know about the universe that we do know about it.

    • Re: (Score:3, Funny)

      by mfnickster (182520)

      > The hidden variable itself could be dynamic controlled by another hidden variable.

      You can't fool me, young man! It's variables ALL the way down! :)

  • by Anonymous Coward

    In his model of the universe, everyone has a beard or goatee.

  • And then tweak it to match reality.

    I'm afraid people do that all the time, each one new and different.

    But why do they bother? We already have the ultimate "parameterize and tweak the theory to match reality" theory in String Theory, so why bother with anything else?

    • by Anonymous Coward on Friday August 28, 2009 @10:29AM (#29231509)

      Come up with a generic theory...And then tweak it to match reality.
      I'm afraid people do that all the time, each one new and different.

      Uh...yeah. That is how the scientific process is supposed to work. You form a hypothesis based on what you know already, you test it, and as the results of your tests roll in, you modify the hypothesis accordingly. Form and then tweak. This is the essence of all scientific progress we have made to date.

      Why do you have a problem with this? I'd say the proof is in the pudding.

      But why do they bother? We already have the ultimate "parameterize and tweak the theory to match reality" theory in String Theory, so why bother with anything else?

      Because string theory lacks evidence, and we don't have the technological means to gather much evidence for it (at present). Also, at present, the theory fails to offer much utility (we can't build any useful devices based on string theory).

      Your attitude sounds a bit scarey. I read it as, "we already KNOW the truth, so why continue looking?" This very attitude inhibited scientific progress for most of human history. I wonder if it also inhibits you?

    • by blueg3 (192743)

      This argument only seems relevant if your generic theory is completely generic; that is, with the proper choice of parameters, it can be exactly equal to any alternative theory. This is true neither of string theory nor physics-as-cellular-automata.

  • by neo (4625)

    Well that's a relief. I thought everything was my fault.

  • by etymxris (121288) on Friday August 28, 2009 @10:18AM (#29231353)

    Bell's inequalities fall apart if current particles can "know" about future measuring devices. However, for particle physics, neither direction of time is privileged. Particles are just as likely to be influenced by future interactions as they are by past interactions. Because of this, there is no "action at a distance". Influences travel along the backwards light cone and remain perfectly relativistic.

    This simple, straightforward solution has been largely ignored.

    Note that most interpretations of quantum mechanics are explicitly time asymmetric due to the "collapse" caused by observation. Cramer's transactional theory is an exception, it is symmetric and there is no collapse, but it doesn't get much attention.

    • Re: (Score:2, Interesting)

      by Anonymous Coward

      Exactly, it seems that most quantum mechanicists assume that the fundamental equations must be hyperbolic in nature. However, general relativity admits solutions with closed time-like curves. This means that a theory combining quantum mechanics and general relativity must as well. (Since in the classical limit it must reduce to general relativity.) Closed time-like curves mean that forward-evolving your hyperbolic equations of motion is impossible. In effect, the loops in time cause future boundary con

    • Re: (Score:2, Insightful)

      by medv4380 (1604309)

      However, for particle physics, neither direction of time is privileged.

      Einstein's Law of Causality states pretty clearly that Time is Uni-driectional, and you'd have to present a pretty solid proof to disprove the Law of Causality. People have tried but short of building a time machine I'm pretty sure the Law of Causality isn't about to fall just yet.

    • by shma (863063) on Friday August 28, 2009 @11:50AM (#29232625)

      Particles are just as likely to be influenced by future interactions as they are by past interactions

      This seems to be a poor understanding of time reversal symmetry. Particle physics works if you run time forward, or if you flip its sign and run time backwards. But that does not mean the same thing as what you said above. You can look at an experiment with each event in reverse, but you can't, for instance, say that event 2 was caused by event 1, but event 1 was caused by event 3. It only can follow the laws of physics if the causal order is 123 or 321.

      The idea of 'backwards' causation has obvious major problems. First of all, you run into causal paradoxes. But more importantly, if the outcome of your experiment rests on future events, how can you do science? Every result becomes meaningless because you don't know if a future event caused it.

    • Cramer's transactional theory is an exception, it is symmetric and there is no collapse, but it doesn't get much attention.

      As far as I know, Cramer's "theory" doesn't make any testable predictions. Hence, it's not actually a theory, it's more like religion or philosophy.

    • by Weezul (52464)

      Isn't Bohmian Mechanics a perfectly solid hidden variable theory that handles this?

  • The phrase "spin on it" clearly means different things to different physicists but not having rotational symmetry sounds like more than just a big flaw it sounds like the sort of flaw that you really should try and fix before saying that you've just proved huge numbers of physicists wrong.

    Its a mind-bending idea to model the universe in this way and personally I think it will fail because of H2G2

    "Some people believe that if man understands the universe then it will be automatically replaced by one even more

  • by BigGar' (411008) on Friday August 28, 2009 @10:31AM (#29231547) Homepage
    If Stephen Wolfram turns out to be correct, his ego will collapse into a singularity form the rapid mass inflation it will under go, taking the Earth with him.
    • Actually if Stephen Wolfram turns out to be correct then his ego must be defined by Rule 110 [wolfram.com] which, as has already been proven, is universal; it expands forever and is full of hot gasses.

  • If anybody here can give a short explanation on how this gets around these proofs, I would be grateful. I remember being pretty convonced by the proof and did not see a way around it. Although, personally, I believe that hidden variable fits reality better, as entanglement with non-determinism needs an extension of the model of the Universe, while "hidden variable" can get by without. Being a CS, I prefer simpler solutions any time ;-)

    • by ceoyoyo (59147)

      It allows non-local influences. The hidden variable proof assumes a local universe.

    • by mbone (558574)

      See my response below - it has to be either non-local, non-causal or exceed the speed of light. (These are of course coupled possibilities.) If he has found another way around Bell's Theorem, I bet he would be touting that, not cellular automata.

      • by gweihir (88907)

        Hmm, yes, I think that would do it. Thanks.

        Seems to me that the Quantum-Theory people know a lot less at this time than some of them pretend to.

        • by ceoyoyo (59147)

          Not exactly. These are all different interpretations of quantum theory. The interpretation most people think IS quantum mechanics is called the Copenhagen interpretation. There have been others right from the beginning. They all use the same equations and produce the same results, but the story that goes along with them is different.

  • The invocation of Hilbert space in the article suggests a LINEAR cellular automata. It would suggest the possibility of any two points in space affecting each other through a very long, but singular line. The concept is akin, if I understand it correctly, to saying that the entire universe is one long line in Hilbert space and thus each iteration of movement affects all others.

    but, IANAP

  • by internic (453511) on Friday August 28, 2009 @11:13AM (#29232119)

    Firstly, I find the title of the submission a little odd. I mean, Entanglement can easily be understood as "deterministic" in a sense in conventional quantum mechanics. The generation of entanglement via the Schroedinger equation is quite deterministic. What's usually understood as non-deterministic is what happens when you measure.

    I saw a talk by t'Hooft a number of years ago (I actually had lunch with him and my adviser). He was talking about a similar idea then, and my interpretation was that it evaded Bell's Theorem by being a non-local hidden variables theory. I haven't read the paper, so I'm not certain if this new idea is significantly different.

    For background: Bell's Theorem is a result that shows that a local realistic hidden variables theory (a theory where each, say, particle has some hidden degree of freedom that determines the outcome of a measurement on it before the measurement is made) cannot reproduce the results of quantum mechanics for an entangled quantum state. To get around this obstacle, it's generally said that you either have to give up determinism (things don't have one specific state, etc. , before they're measured) or locality (the outcome of an experiment in one place may be totally changed by events happening at the same time arbitrarily far away)

  • As I understand it, there are hidden variable theories completely in sync with experiment. But they are experimentally indistinguishable from true randomness - and hence serve no scientific purpose (although answering Einstein's famous objection, "God does not play dice"). A hidden variable theory where the "hidden" variables can be deduced by experiment "inside" the universe is no longer a truly "hidden" variable theory.

    • by blueg3 (192743)

      "Hidden" in this sense doesn't mean "impossible to deduce by experiment" but simply "currently unknown to us".

  • 3 choices (Score:5, Informative)

    by mbone (558574) on Friday August 28, 2009 @11:34AM (#29232405)

    Hidden variables in this case should be thought of as a hidden micro-states. A hidden variable theory would have quantum mechanics be something like thermodynamics; i.e., a theory that is not really basic, but appears so as we cannot see the fine scale true reality. Einstein was convinced that this had to be the case.

    The tests of Bell's Theorem shows that no locally causal hidden variable theory is viable. This says basically that one of these must be the case

    There are no hidden variables (i.e., true quantum uncertainty applies, and quantum mechanics is correct).

    The speed of Light can be violated (i.e., there are hidden states that can exchange information faster than the speed of light). This implies, by the way, causality failures would be possible, so that in principle you could do something like kill your grandfather and prevent your own existence.

    There is action at a distance (i.e., the theory is non-local).

    There has long been a viable theory, that of Bohm [wikipedia.org], that replicates normal quantum mechanics. It's non-local.

    I cannot tell from a read of the article (and without seeing the underlying paper) if 't Hoof has a non-local theory or just how he stays consistent with Bell's Theorem.

    • by jbengt (874751)

      The tests of Bell's Theorem shows that no locally causal hidden variable theory is viable. This says basically that one of these must be the case
      There are no hidden variables (i.e., true quantum uncertainty applies, and quantum mechanics is correct).
      The speed of Light can be violated (i.e., there are hidden states that can exchange information faster than the speed of light). This implies, by the way, causality failures would be possible, so that in principle you could do something like kill your grandfather and prevent your own existence.
      There is action at a distance (i.e., the theory is non-local).

      Or, since we're talking about quantum states, it could be that any combination of the three and not the three are the case, only to collapse to one (or more) of them when you make your observation.

    • by Ryvar (122400)

      The speed of Light can be violated (i.e., there are hidden states that can exchange information faster than the speed of light). This implies, by the way, causality failures would be possible, so that in principle you could do something like kill your grandfather and prevent your own existence.

      Not necessarily. One possible alternative is the Novikov Self-Consistency principle [wikipedia.org], which posits that if a faster-than-light communication or a classical 'time travel' ever did occur, the probability of those events

      • by mbone (558574)

        Yes, and I have to wonder if that sort of self-cancelation could be built into a cellular autonoma model. That would be interesting.

        I recently read Alastair Reynolds House of Suns [amazon.com], and this deals with causality violations, by name. I don't think his solution would work as physics, but it's not impossible, and I thought it was very cool that he recognized and described the issue.

  • Konrad Zuse? (Score:2, Insightful)

    by Haxamanish (1564673)
    Why ascribe the idea's of Konrad Suse [wikipedia.org] to Wolfram?? Calculating space, 1967 (PDF) [idsia.ch]
  • anyone who's ever tried to wind up power cords or ethernet cables knows that.

  • We are describing the universe with mathematics. Mathematics are wholly invented by man. The rules are deterministic. Where we get unexpected results, such as with chaos mathematics, all we can do is map the boundaries and boggle.

    Eventually, when you do enough math, everything you can understand about the universe with math alone is going to look deterministic because of the semantic properties of the language you are using to describe it.

    So the question is, what are we leaving out by boiling the universe d

  • Sounds like the Autoverse in Greg Egan's novel "Permutation City".

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