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Simulations Back Up Theory That Universe Is a Hologram 433

Posted by Soulskill
from the not-the-star-trek-kind dept.
ananyo writes "A team of physicists has provided some of the clearest evidence yet that our Universe could be just one big projection. In 1997, theoretical physicist Juan Maldacena proposed that an audacious model of the Universe in which gravity arises from infinitesimally thin, vibrating strings could be reinterpreted in terms of well-established physics. The mathematically intricate world of strings, which exist in nine dimensions of space plus one of time, would be merely a hologram: the real action would play out in a simpler, flatter cosmos where there is no gravity. Maldacena's idea thrilled physicists because it offered a way to put the popular but still unproven theory of strings on solid footing — and because it solved apparent inconsistencies between quantum physics and Einstein's theory of gravity. It provided physicists with a mathematical Rosetta stone, a 'duality', that allowed them to translate back and forth between the two languages, and solve problems in one model that seemed intractable in the other and vice versa. But although the validity of Maldacena's ideas has pretty much been taken for granted ever since, a rigorous proof has been elusive. In two papers posted on the arXiv repository, Yoshifumi Hyakutake of Ibaraki University in Japan and his colleagues now provide, if not an actual proof, at least compelling evidence that Maldacena's conjecture is true."
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Simulations Back Up Theory That Universe Is a Hologram

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  • by Sigvatr (1207234) on Wednesday December 11, 2013 @04:27PM (#45663449)
    I have no idea what any of this stuff means, but I'm going to post it on my Facebook and claim that this is what I thought all along anyway.
  • The matrix is real???
    • Re: (Score:2, Interesting)

      by Anonymous Coward

      It changes nothing since it's always been more probable that we're in a simulation than not. If there is only one real world and we can create a complete simulation of it, then we can run a second simulation of it. If there's two simulations and one real world, it's more likely you're in one of the simulations than in the real world.

      Personally, I'd rather be living on the event horizon of a 4D black hole instead of someone's hologram. Are these two theories mutually exclusive?

      • by muphin (842524)
        Does that mean,
        "Dimensions" are alternate simulations, like we do with super computers? parallel processing.
      • by Kielistic (1273232) on Wednesday December 11, 2013 @04:56PM (#45663783)
        I think it's more probable that you just have no idea what you're talking about.
      • by quarterbuck (1268694) on Wednesday December 11, 2013 @06:34PM (#45664855)
        I think you missed a bit there.
        Any simulation of the world will be as complex as the original. So if you build a full simulation of the real world, you'd double the information complexity of the world. So that wouldn't work.
        One thing that might work is if you simulate regions of the "world" just in time -ie the things you see are being simulated as you look for them. That ties that simulation to a Matrix like world - each person effectively has his own world and they can be independent of each other.
        Another possibility is that we are in a limited simulation - some have said that quantum theory shows the graininess of the simulation and that relativistic speed limits limit the size of the canvas on which the world is being painted (ie you only have to simulate as far as the edge of the canvas, nothing outside it affects whatever is inside).
        In either of these cases, you cannot (be guaranteed to be able to) run a simulation within a simulation.
      • It changes nothing since it's always been more probable that we're in a simulation than not.

        Not in the least.

        If there is only one real world and we can create a complete simulation of it

        That's why. Parlor thoughts only. You cannot fit a complete description of reality in said reality. Recursion.

    • by jeffb (2.718) (1189693) on Wednesday December 11, 2013 @04:39PM (#45663573)

      Quite a lot older. [wikipedia.org]

      • by DexterIsADog (2954149) on Wednesday December 11, 2013 @04:52PM (#45663739)
        Oh, nonsense. The Matrix is not an accurate description of this theory, and Plato's metaphor is only coincidentally similar in outline to it.

        Your point is like people who say, "the Old Testament forbids the eating of shellfish like shrimp, and we know now that shrimp is high in cholesterol, so that book is an excellent source of dietary wisdom."
    • by Common Joe (2807741) on Wednesday December 11, 2013 @04:51PM (#45663733) Journal

      I read the FTA and I didn't get any proof that we were living in a simulation at all. The article basically says some physicists ran two simulations for a black hole -- one with quantum theory (single dimension) and the other with a (more traditional) 10-dimensional model. The results matched.

      Several take aways: 1) Great work by the physicists 2) I thought the standard models had eleven dimensions and not ten 3) I still don't know what they are talking about because this stuff is way beyond me 4) There is no mention about whether this proves one way or another that our universe is a hologram or a simulation.

      The FTA is throwing around the word hologram, but IMHO that is a bit a stretch. Or maybe I don't know the official scientific definition of a hologram.

      • FTA = The friggin article.

        I don't feel that tired, but I think my comment speaks for itself. I need to go take me a one dimensional holo-nap or something.

      • by lgw (121541) on Wednesday December 11, 2013 @05:18PM (#45663997) Journal

        Eleven vs Ten dimensions is at the heart of the "hologram" thing. The universe as a hologram (nothing at all to do with a simulation) is a metaphor for how the math worked out in a very surprising way from two different directions.

        In the study of black holes, a block hole represents the maximum entropy is is possible to have in a given volume. That there is a maximum possible information needed to completely describe a volume of space. Surprisingly that limit grows with surface area, not volume. By analogy, this is like saying you could take a holographic recording of a volume at its surface, and completely reconstruct the volume from that data. But the "holographic universe" is just an analogy for the very odd result that all the information describing a volume of space "fits" in 2 dimensions. It's best not to read too much into that because the limit here is really quite high, the maximum possible information is on the order of the surface area of a sphere measured in plank-lengths - vastly more bits than is likely relevant to anything.

        Inspired by this work, but in completely unrelated theory, it was found that the 11-diminsional quantum model can be completely captured in a 10-diminsional model that includes gravity. The presence of gravity in the universe "flattens" the state needed to describe it by one dimension. This was to me a much more interesting result that the black hole result (because the numbers there were so high it wasn't really a limit at all). Qualitatively all this is not that surprising in glorious hindsight, because gravity does limit the possible ways to arrange matter in the universe: black holes mean any arrangement with too much too close together collapses the information needed to describe it into just a few numbers. How that translates into needing 1 less dimension in quantum mechanics is far beyond me.

        • by Prune (557140)
          >That there is a maximum possible information needed to completely describe a volume of space. Surprisingly that limit grows with surface area, not volume.

          This is equivalent to the Bekenstein bound, where the maximum entropy/information density is proportional to the radius and mass/energy. In the extreme case, for the latter substitute the Schwarszchild radius for that mass/energy, giving a formula proportional to the square of the radius--i.e. surface area, as you wrote.

          > It's best not to read
      • by pla (258480)
        I read the FTA and I didn't get any proof that we were living in a simulation at all.

        Because it doesn't claim that. Hologram != Simulation.


        The FTA is throwing around the word hologram, but IMHO that is a bit a stretch. Or maybe I don't know the official scientific definition of a hologram.

        It just means that our universe seems to have more dimensions than it really does, for certain purposes. By analogy with a visual hologram, which looks 3d but all the depth information resides entirely in the in
      • by OakDragon (885217) on Wednesday December 11, 2013 @06:03PM (#45664469) Journal

        ...2) I thought the standard models had eleven dimensions and not ten ...

        Look, the standard model has these eleven- *CRASH* - Oy! I mean ten - TEN dimensions!

      • by quarterbuck (1268694) on Wednesday December 11, 2013 @06:43PM (#45664985)
        A very crude analogy would be a Fourier transform. If you take a simple wave it is very complicated to describe it in time domain (lots of terms mathematically), but it has a simple mathematical expression in frequency domain with just a single term.
        The physicists have figured out how to simplify the maths. This transformation also has a physical interpretation which is best explained as a hologram. A hologram has information from 3 dimensions scrunched into 2 dimensions, ie when you look at a hologram, it appears to have depth. In a common hologram sticker, that information is encoded in polarization. In the same manner, they seem to say information in a 11 Dimensional world can be scrunched into lesser number of dimensions. Hence the analogy.
  • by occasional_dabbler (1735162) on Wednesday December 11, 2013 @04:28PM (#45663467)
    ...is no longer not even wrong ? [columbia.edu]
    • by DaveV1.0 (203135)
      No, it is still not even wrong, but we are closer to knowing if it could be right or wrong. This is not strong evidence, let alone proof, of string theory. This just gives it a way to be more compatible with relativity. The problem is that it could be just a good approximation of something else.
  • by 140Mandak262Jamuna (970587) on Wednesday December 11, 2013 @04:29PM (#45663479) Journal
    Not only is the universe a hologram, it is actually contained inside R2D2.

    Then they will tell you it is recursive too.

    But it happened long time ago and in a galaxy far away.

  • by PaddyM (45763) on Wednesday December 11, 2013 @04:39PM (#45663567) Homepage

    It's turtles all the way down to turtle prime which is a comic book.

    • by hguorbray (967940)
      guess that means that we are actually in flatland http://en.wikipedia.org/wiki/Flatland

      -I'm just sayin'
    • Are these "turtles all the way down", teen-aged, mutated, and trained in the art of ninjitsu by any chance?

  • On Other Dimensions (Score:5, Informative)

    by SumDog (466607) on Wednesday December 11, 2013 @04:41PM (#45663587) Homepage Journal

    A lot of people might find this a little hokey, especially coming from the journal Nature. The biggest thing to overcome is science fictions deception of other dimensions. A dimension is just another direction. We know about the six directions we can currently move in (3 dimensions) plus time (which we always move forward through at a constant rate; you can slow down how fast you move through time relative to everything else, but it's not noticeable unless you can afford a very very fast vehicle). Here's a great explanation of extra dimensions:

    http://www.phdcomics.com/tv/#010

    The other "Things explained" videos are also really good for understanding more complex physics concepts.

    • Re: (Score:2, Insightful)

      by Anonymous Coward

      I can move in an infinite* number of directions, but in 3D space I can put in one point only 3 lines which are perpendicular to each other.

      If we have more dimensions, we just replace the word "perpendicular" with "orthogonal".

      --
      * Or a very very high number if space is finite & discrete.

    • time (which we always move forward through at a constant rate

      I think of it as: we always move through spacetime at a constant rate - you can change the direction of your path relative to anything else, which leads to time dilation as you do swap motion through (another relatively moving observer's) time for motion through (another relatively moving observer's) space. Except time is inverted and wibbly wobbly and there is stuff.

    • Can you make the parallel with the 7D experience I get at the cinema? The fact that I'm still missing 3 or 4 dimensions pisses me off!

      The universe: it goes all the way to 11! ...but you really only need 10 ;-)
  • String theory et al give us some testable predictions? Until then its just a crock of bullshit that has wasted 30 years of physics (though certainly enhanced the bottom line of many a journal).

    • The search for equations to more accurately describe the observable universe is often first formed as a hypothesis, then once the hypothesis is formalized and can be tested it may become a Theory or Law. One can come to such equations through direct observation, such as thermodynamics or Newtonian Gravity, or be theoretical until proven, like Einstein's curved space-time. In other words one can observe something strange then attempt to explain it, or formulate explanations that cover known observations an

  • ... where my evil twin is residing!

  • by BitterOak (537666) on Wednesday December 11, 2013 @04:49PM (#45663711)
    There's more about it here [wikipedia.org]. This recent work basically suggests that the theory might be true. It is a doubly useful theory in that it allows certain difficult problems in string theory to be solved in the language of conformal field theories and vice versa. If nothing else, it means string theory can be used as a computational tool in certain problems of condensed matter physics even if string theory doesn't pan out as a theory for quantum gravity. But it also makes string theory more likely as a theory for quantum gravity as it makes it in some sense compatible with the holographic principle, which among other things provides a solution to the information paradox [wikipedia.org] of black holes.
    • It's somewhat disturbing to me that in addition to not understanding the summary, I also don't understand your explanation or for that matter, what the topic under discussion even might be (other than some vague physics thing).

      Also I realized apparently I don't know what a holograph is.
      • by tlhIngan (30335) <slashdotNO@SPAMworf.net> on Wednesday December 11, 2013 @05:28PM (#45664099)

        It's somewhat disturbing to me that in addition to not understanding the summary, I also don't understand your explanation or for that matter, what the topic under discussion even might be (other than some vague physics thing).

          Also I realized apparently I don't know what a holograph is.

        Basically, there are two major concepts.

        First, is duality. This is where two models can represent the same system (they are duals of each other). The thing with duality is that in many cases, a problem that is impossible to solve in one model may be trivially done in another. You may know the duality between time-domain and frequency-domain systems - a convolution in one is a multiplication in the other (which is handy for some really difficult convolutions).

        The other concept is a hologram. Take a traditional hologram you can buy as a souvenir - it's just a flat piece of transparent material (glass or plastic), yet look through it and you see a 3D image hovering in space - projected if you will, in 3D. And it is 3D, because you can look around the object. Yet the object is stored on a 2D medium. (FYI - the same concept applies to holographic sights - the dot is projected on the target in 3D space). Holograms are useful because they can cast higher dimensional spaces into lower dimensional spaces, yet retain the original resolution and details of the higher dimensional space (or how they get a 3D projection on a 2D surface).

        Holographic theory is one where our 3D world is actually on a 2D surface. Like a hologram.

        Now, what the results are is that they found a set of dual systems that represent reality - between string theory and quantum mechanics using holographic theory. In other words, they could do a calculation using string theory and have the results line up with quantum mechanics (and holograms). By proving this, a difficult problem in quantum mechanics can be translated to string theory and be easily solved there, then the results translated back, which gives the same answer as if you did it the hard way.

    • by hweimer (709734)

      Too bad that our universe is neither AdS (the cosmological constant is positive) nor ten-dimensional as in the papers.

  • Of course, this could mean that half of the potential alternative projections of reality will turn out to be slightly shittier versions of what we have now.

    But the other half will have jet packs and rocket cars! And no marketing directors!

  • Now that we are searching for evidence of this hologram, and may be close to establishing something approaching 'proof', won't the folks projecting the hologram alter the program to make it more difficult for us to determine if we are living in a hologram and thus negate our findings which will lead us to do more research and in turn cause the hologram to be changed again? Rinse and repeat.

  • Ampletuhedrons? (Score:4, Interesting)

    by Kismet (13199) <pmccombs AT acm DOT org> on Wednesday December 11, 2013 @05:05PM (#45663857) Homepage

    Is this related to the work that Arkani Hamed and Trnka are doing with Ampletuhedrons? They have discovered a geometry that simplifies calculations and that suggests space and time might not be fundamental to physics.

  • What this means (Score:5, Informative)

    by Fuseboy (414663) on Wednesday December 11, 2013 @05:07PM (#45663889) Homepage

    Someone clever was working out the maximum entropy of a black hole, and found that (unexpectedly) it was proportional to the surface area of the event horizon, not its volume. After some more thought, other clever people found that the full state of every particle that falls into a black hole remains encoded as oscillations and deformations of its surface area.

    This leads to the realization that the despite the fact that a black hole's event horizon is seemingly much simpler than a full-dimensional portion of a universe, it's theoretically possible that it's just as rich a simulation. Perhaps the "real" representation of the universe is actually just a rippling membrane, and the 3D view we see around us is just an alternate interpretation. This is where the word "hologram" comes in - it's only an analogy (because flattish holograms seem to encode 3D data).

    Now, the word "real" is misleading - neither representation is 'more true', it's just that the fewer-dimensional representation might be a lot simpler. A comparable situation is the way the earth goes around the sun, or the sun goes around the earth. A stationary sun makes models of the planetary orbits a heck of a lot simpler, but a stationary earth makes it a lot easier to give directions to your party.

    All of this was theoretical until this recent finding. The researches created two mathematical models of the universe - one of them ten-dimensional (similar to some forms of modern theories of our universe, though the article points out their model was simpler). The other model was a one-dimensional universe filled with ideal springs. These models were identical, in the same way as the 3D universe and the event horizon - they're alternate ways of calculating the same thing.

    The researchers discovered that simulations in both of these universe models have the same output - in other words, they do seem to be different ways of describing the same universe.

  • and earth is Rimmer world?

  • by Kaenneth (82978) on Wednesday December 11, 2013 @05:15PM (#45663965) Homepage Journal

    The way I think of the universe, is like a 11 dimensional sphere of putty, that got hit with a hammer. (aka the big bang).

    So, the sphere got deformed spraying outward in 3 dimensions (space) while flying off into a 4th (time) and the other 7 dimensions got compressed.

    A Particle is a bit of energy caught in a loop around some number of those 7 dimensions, each combination of possible wrapping gives a different fundamental particle, with antiparticles having the same wrap, but opposing spin.

    Light/radio 'waves' are caused by the photons looping around one of the higher dimensions, not one of our 3 spatial dimensions, which is how it is travelling in a straight line space, yet still taking a wavering path; like a piece of string wrapped around an infinitesimally small cylinder.

    But that's just my mental model, it work well enough to keep me from going mad (I think)

  • by hopffiber (3460857) on Wednesday December 11, 2013 @05:15PM (#45663969)
    So, the headline is quite wrong. Nothing in this work has directly to do with our universe, nor does it show that we live in a hologram. What it does do is provide some further evidence for a string theory conjecture called AdS/CFT. This conjecture says that "string theory in d dimensions" is precisely the same as "conformal field theory in d-1 dimensions". This is cute, since it lets us calculate some things, for example, one might be interested in calculating something in some field theory, but it is very difficult to do. AdS/CFT lets us translate that thing into a string theory thing, which usually is easier to compute. So people working in condensed matter physics, particle physics and QCD are actually using this string theory conjecture as a computational tool. However, AdS/CFT tells us nothing about our universe, since we know that the type of string theories it talks about can't describe our universe. So it is "only" a useful toy model and computational tool. The article is about that some guys have run computer simulations to calculate something on both sides, so both on the string side, and in the field theory side, and what they get match, as it should if the conjecture is true. This is nice and lends further evidence to the conjecture, but there is plenty of other evidence already known, both numerical and theoretical. So I fail to see how this is important or newsworthy, it feels mostly like useless hype.
  • Cool, but my head hurts trying to understand the theory.

  • by volvox_voxel (2752469) on Wednesday December 11, 2013 @08:24PM (#45666121)
    Dave Barry on College - "After you've been in college for a year or so, you're supposed to choose a major, which is the subject you intend to memorize and forget the most things about. Here is a very important piece of advice: be sure to choose a major that does not involve Known Facts and Right Answers. This means you must not major in mathematics, physics, biology, or chemistry, because these subjects involve actual facts.."

    "So you should major in subjects like English, philosophy, psychology, and sociology -- subjects in which nobody really understands what anybody else is talking about, and which involve virtually no actual facts. I attended classes in all these subjects, so I'll give you a quick overview of each:"

    ...

    "PHILOSOPHY: Basically, this involves sitting in a room and deciding there is no such thing as reality and then going to lunch. You should major in philosophy if you plan to take a lot of drugs...."

    http://users.soe.ucsc.edu/~martine/light/barrycollege.html [ucsc.edu]

    Unfortunately, some aspects of physics are starting to sound like Dave Barry's take on Philosophy..

  • by Remus Shepherd (32833) <remus@panix.com> on Wednesday December 11, 2013 @08:52PM (#45666371) Homepage

    I got into this discussion too late to be noticed, but I feel the need to help people understand that this theory is *NOT* stating the universe is a simulation. Projections are not simulations.

    What the theory suggests is that of all the dimensions we know about (the article mentions 6, which is how many dimensions you get with one flavor of string theory), some of them are illusion. Like a hologram -- a 2D plastic or glass toy that displays a 3D image. The universe does not contain 6 dimensions; it contains a smaller number, and the rest of the dimensions only appear to be there.

    It's likely that the universe contains at least three dimensions, because we would have noticed non-isomorphic behavior in space. But the jury is still out on whether the fourth dimension -- Time -- is an illusion. The same goes for the fifth and sixth dimensions.

    None of this says anything about the universe being simulated. That's a philosophical question that physics will probably never be able to answer.

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